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Can anyone tell me what kind of insect (if it is one) is this… !! Or is it the pupa of some insect?
Well I don't think that the whole big thing is the insect itself, it appears to be just a kind of protection or shelter which moves along with the tiny little thing that keeps on popping out and going it so as to move.
This is mostly a guess and loose suggestion, since the picture is not very clear (would need to see the larvae in more detail). However, Bagworm moths (Psychidae), Case moths (Coleophoridae) and Caddisfly larvae (Trichoptera, almost exclusively aquatic) all build similar cases. They construct their cases out if silk and often include debris, pebbles and other materials. I wouldn't be surprised if the larvae in your picture belongs to one of the first two taxa. Bagworm moths and Caddisflies generally include lots of external materials in their larval cases, which could point to Case moths for your specimen (which seems to have a weaker case mostly made of silk).
Here are two pictures of first a UK Case moth larvae (Coleophora deauratella) followed by a Bagworm moth (Dahlica triquetrella), just as comparisons. If you do google image searches of "group name + larvae" you will see many examples of what they can look like.
And just as a cool example - the larvae often use random material lying around to build their cases, which can give the following result, if caddisfly larvae are bred in a tank containing pieces if gold and pearls. For further information see this link.
It's a household casebearer, a kind of moth larva in the family Tineidae that builds this case around itself.
@fileunderwater is wrong
Insect Pests of Potato
Insect Pests of Potato: Biology and Management provides a comprehensive source of up-to-date scientific information on the biology and management of insects attacking potato crops, with an international and expert cast of contributors providing its contents. This book presents a complete review of the scientific literature from the considerable research effort over the last 15 years, providing the necessary background information to the subject of studying the biology management of insect pests of potatoes, assessment of recent scientific advances, and a list of further readings. This comprehensive review will be of great benefit to a variety of scientists involved in potato research and production, as well as to those facing similar issues in other crop systems.
Insect Pests of Potato: Biology and Management provides a comprehensive source of up-to-date scientific information on the biology and management of insects attacking potato crops, with an international and expert cast of contributors providing its contents. This book presents a complete review of the scientific literature from the considerable research effort over the last 15 years, providing the necessary background information to the subject of studying the biology management of insect pests of potatoes, assessment of recent scientific advances, and a list of further readings. This comprehensive review will be of great benefit to a variety of scientists involved in potato research and production, as well as to those facing similar issues in other crop systems.
Lac-insect for Lac Culture in India: Life Cycle of Lac-insect (with pictures)
Nature has given much for welfare of human beings through animals and their products.
On the other hand human beings never seem to tire of discovering the mysteries of nature. But the animals seem to be greater experimenters as some of them have astounded most human beings by their complex, strange and at times bizarre performance. One of such performer known to man from good old days is the tiny insect that has given a very valuable product in the form of lac, to the civilization of man.
Lac is a natural resin of animal origin. It is secreted by an insect, known as lac-insect In order to obtain lac, these insects are cultured and the technique is called lac-culture. It involves proper care of host plants, regular pruning of host plants, propagation, collection and processing of lac.
Lac has been used in India from time immemorial for several purposes, from the epic of Mahabharat it has been recorded that Kauravas built a palace of lac for the destruction of Pandavas. We come across references of lac in the Atharvaveda and Mahabharata, so it can be presumed that ancient Hindus were quite familiar with lac and its uses.
Scientific study of lac started much later. In 1709 Father Tachard discovered the insect that produced lac. First of all Kerr (1782) gave the name Coccus lacca which was also agreed by Ratzeburi (1833) and Carter (1861). Later Green (1922) and Chatterjee (1915) called the ac- insect as Tachardia lacca (kerr). Finally, the name was given as Laccifer lacca.
A number of species of lac insects are known, of this Laccifer lacca is by far the most important and produces the bulk of the lac for commerce. It belongs to—
The insects live as a parasite, feeding on the sap of certain trees and shrubs. The important trees on which the lac insects breed and thrive well are –
Kusum (Schleichera trijuga)
Before coming to the actual mechanism of lac secretion and its processing, it is advisable for a lac-culturist to have detailed knowledge of lac insect and its life cycle. The adult lac insect
Shows a marked phenomenon of sexual dimorphism. The male and female insect varies in shape, size and also in presence or absence of certain body parts.
Structure of Male Lac-insect:
It is larger in size and red in colour. The body is typically divided into head, thorax and abdomen. The head bears a pair of antennae and a pair of eyes. Mouth parts are absent so a male adult insect is unable to feed. Thorax bears three pairs of legs. Wings may or may not be found. (Fig. 33 a, b).Abdomen is the largest part of the body bearing a pair of caudal setae and sheath containing penis at the posterior end.
Structure of Female lac-insect:
It is smaller in size. Head bears a pair of antennae and a single proboscis. Eyes are absent. Thorax is devoid of wings and legs. (Fig. 34. b) The loss of eyes, wings, and legs are due to the fact that the female larvae after settling down once never move again and thus these parts become useless and ultimately atrophy. Abdomen bears a pair of caudal setae. It is female lac insect which secretes the bulk of lac for commerce.
After attaining the maturity, males emerge out from their cells and walk over the lac incrustations. The male enters the female cell through anal tubular opening and inside female cell it fertilizes the female.
After copulation, the male dies. One male is capable of fertilizing several females. Females develop very rapidly after fertilization. They take more sap from plants and exude more resin and wax.
The females after fertilization are capable of producing eggs. But it has been noticed in case of lac insects that the post fertilization developments start when the eggs are still inside the ovary. These developing eggs are oviposited into the incubating chambers (formed inside the female cell by the body contraction of females). A female is capable of producing about one thousand eggs (average 200-500). Inside incubating chamber, the eggs hatch into larvae.
The larvae are minute, boat shaped, red coloured and measure little over half millimeter in length. Larva consists of head, thorax and abdomen. Head bears a pair of antennae, a pair of simple eyes and a single proboscis. All three thoracic segments are provided with a pair of walking legs. Thorax also bears two pairs of spiracles for respiration. Abdomen is provided with a pair of caudal setae.
These larvae begin to wander in search of suitable centre to fix them. This mass movement of larvae from female cell to the new off-shoots of host plant, is termed as “swarming”.
The emergence of larvae from female cell occurs through anal tubular opening of the cell and this emergence may continue for three weeks. The larvae of lac are very sluggish and feed continuously when once they get fixed with the twig. In the meantime the larvae start secreting resinous substance around their body through certain glands present in the body. After some-time the larvae gets fully covered by the lac encasement, also known as lac cell. Once they are fully covered, they moult and begin to feed actively.
The cell produced by male and female differ in shape, and can be easily distinguished sometimes later. Male cells are elongated and cigar shaped. There is a pair of branchial pores in the anterior side and a single large circular opening covered by the flap in the posterior side. (fig. 26, a). It is through the posterior circular opening that the matured male lac insect emerges out of its cell.
Female cell is oval, having a pair of small branchial pores in anterior side and a single round anal tubular opening in posterior side. Through the anal tubular opening are protruding waxy white filaments, secreted by the glands in the insects body, which is an indication that the insect inside the cell is alive and is in healthy condition. These filaments also prevent the blocking of the pore during excess secretion of lac.
Larvae moult in their respective cells. It is the second stage larva which undergoes pseudopupation for a brief time, whereby it changes into adult stage. Now the male emerges out from its cell, moves on lac incrustation and enters the female cell for fertilization. In this way the life cycle is completed.
Lac is a resinous substance secreted by certain glands present in the abdomen of the lac insects. The secretion of lac begins immediately after the larval settlement on the new and tender shoots. This secretion appears first as a shining layer which soon gets hardened after coming in contact with air.
This makes a coating around the insect and the twig on which it is residing. As the secretion continues the coating around one insect meet and fuses completely with the coating of another insect. In this way a continuous or semi-contmuous incrustation of lac is formed on the tender shoots.
Cultivation of Lac:
Cultivation of lac involves proper care of host plants, regular pruning of host plant, infection or inoculation, crop-reaping, control of insect pests, and forecast of swarming, collection and processing of lac.
The first and perhaps the most important prerequisite for cultivation of lac is the proper care of the host plant. It is the host plants on which lac insects depend for their food, shelter and for completion of their life cycle. There are two ways for the cultivation of host plants. One is that plants should be allowed to grow in their natural way and the function of lac-culturist is only to protect and care for the proper growth of plants.
Another way is that a particular piece of land is taken for the purpose and systematic plantation of host plant is made there. Regular watch is necessary in this case by providing artificial manures, irrigation facilities, ploughing and protecting the plants from cattle and human beings for which the land should be fenced. The larvae of lac insects are inoculated on host plants only after the host plants have reached a proper height.
The lac larvae feed on the cell sap by inserting their proboscis in the tender twigs. The proboscis can only be inserted in the tender young off-shoots. For this before inoculation, prunning of lac host plants is necessary. The branches less than an inch in diametre are selected for pruning. Branches half inch of less in diametre should be cut from the very base of their origin. But the branches more than half inch diametre should be cut at a distance of 1 ½ inch from the base.
The method by which the lac insects are introduced to the new lac host plant is known as inoculation. This may be of two types, namely “Natural infection” and “Artificial infection”. When infection from one plant to other occurs by natural movements of insect, it is called natural infection. This may be due to overcrowding of insect population and nonavailability of tender shoots on a particular tree.
Artificial infection takes places through the agencies other than those of nature. Prior to about two weeks of hatching, lac bearing sticks are cut to the size of six inches. They are called“Brood lac”. Brood lacs are then kept for about two weeks in some cool place.
When the larvae start emerging from this brood lac, they are supposed to be ready for inoculation. Strings со be used for tieding the brood lac with the host plant may be of different types in longitud infection the brood lac is tied in close contact with host branches. In lateral infection the brood lac is tied across the gaps between two branches. In interlaced method, brood lac is tied among the branches of several new shoots.
The lac insects repeat its life cycle twice in a year. There are actually four lac crops since the lac insects behave in two ways either they develop on Kusum plants or devlop on plants other than Kusum. The lac which grows on Non-Kusum plants is called as “Ranjeem lac,” and which grows on Kusum plant is called as “Kusumi lac. Four lac crops have been named after four Hindi months in which they are cut from the tree. They are as follows:
Lac larvae are inoculated in June-July. Male insect emerges m August-September. Female give rise to swarming larvae in October-November and the crop is reaped in Kartik (October and November).
Larvae produced by Katki crop are inoculated in October-November, male insects emerges in February-March, females give rise to swarming larvae m June-July, the crop is reaped in Baisakh (April-May).
Lac larvae are inoculated in June-July, male insect emerges m September, female give rise to swarming larvae in January-February and crop is reaped in Aghan (December-January).
The larvae produced by Aghani crop is inoculated in the month of January- February, male emerges in March-April, female give rise to swarming larvae in June- July and the crop is reaped in the month of Jeath (June-July).
The time of infection with swarming larvae, the time of emergence of male insects, the time of reaping the crop, and the time of producing swarming larvae by female etc., are shown m tabular form below
Scraping and Processing of lac:
Lac cut from the host plant is called as “stick lac”. Lac can be scraped from the twigs before or after the emergence of larvae. If it is used for manufacturing before the emergence of larvae, the type of lac produced is called as “Ari lac” and if it is used for manufacturing purpose after swarming of larvae has occurred, the lac is said to be Phunki lac”.
The scraping of lac from twig is done by knife, after which they should not be exposed to sun. The scraped lac is grinded in hard stone mills. The unnecessary materials are sorted out In order to remove the finer particles of dirt and colour, this lac is washed repeatedly with cold water.
Now at this stage it is called as “Seed lac” and is exposed to sun for drying. Seed lac is now subjected to the melting process. The melted lac is sieved through cloth and is given the final shape by molding. The final form of lac is called “Shellac”. Colour or different chemicals may be mixed during melting process for particular need.
Lac Enemies and Their Control:
A lac enemy imposes a challenge to the lac culturist, as they not only decreases the population of lac insects, but also retard the production and quality of lac. Damage caused to lac insects may be grouped under two heads, (a) damage caused by insects (b) damage caused by animals other than insects. Insect enemies of lac crop may be predators and parasites.
The common parasites of lac insect are known as “Chalcid.” They are small, winged insects which lay their eggs inside the lac coat either on the body of the lac insect or inside the body of the lac insect. The larva which hatches from these eggs feed upon the lac insects, thereby causing mortality of their host. Damage done by this parasite constitute about 5-10% of the total destruction of the lac crop.
Damage done by the predators is of greater intensity (35% of the total destruction). The major predators of lac insects are Eublemma amabilis (the white moth) and Holococera pulverea (the blackish grey moth). They not only feed on lac insects but also destroy the lac produced by term. Squirrels, monkey, rat, bat, birds (wood peckers), man etc., are the enemies other than insects which destruct the lac crop in different ways. Damage is also done by climatic factors such as excess heat, excess cold, heavy rain, and storm and partly by the faulty cultivation methods.
Damage caused by the above mentioned animals can be reduced to certain extent by the use of the following methods.
The amount of damage by infection can be reduced to a greater extent by taking care during the culture of lac insects, especially at the time of inoculation. The brood lac showing the minimum enemy attack should be selected for inoculation and should be cut from the host plant very near to the time of emergence of larvae (about one week before the emergence). This will reduce the chances of parasite attack on the emerging larvae at new place (host).
The brood lac used for inoculation should be removed from the new host’s branches as soon as the emergence of larvae stops (approx. 3 weeks after inoculation). It reduces the chance of transference of enemies to the new host plant from the brood lac. The infected brood lac not fit for inoculation or the used up brood lac should not be retained for long. The lac should be scrapped at once and t e rest may be crushed or dropped into fire in order to destroy the predators and parasites.
The delay m processing also gives chances to the enemy insects to escape into field. So the manufacturers should try to convert stick lac into seed lac as soon as possible. By these cultural methods the future production can be saved from infection to some extent.
During the crop reaping, it is not always possible for the manufacturers to convert the huge amount of stick lac to seed lac at a time. To avoid the spreading of enemies at this time from stocked stick lac simple artificial method can be used. Bundles of stick lac should be tied with stones and immersed in fenced water (river or ponds) for about a week. This kills all the parasitic and predator insects as they cannot survive in water.
It is an indirect method for killing the parasitic and predator insects. For this purpose hyper-parasitic insects are used which attacks the parasitic insects of lac and kill them. These hyper-parasitic insects are however, not harmful for lac crop.
Use of Lac:
Lac has been used for the welfare of human beings from the great olden days No doubt the development of many synthetic products have made its importance to a little lesser degree, but still it can be included in the list of necessary articles. Lac is used in making toys, bracelets, sealing wax, gramophone records etc.
It is also used in making grinding stones, for filling ornaments, for manufacturing of varnishes and paints, for silvering the back of mirror, for encasing cable wires etc., Waste materials produced during the process of stick lac is used for dying purpose. Nail polish is a good example of the by-product of lac.
Composition of Lac:
Lac is a mixture of several substances, of which resin is the main constituent. The approximate percentage of different constituents of lac is given below:
Albuminous matter – 5 to 10%
Present Position of this Industry in India:
Lac is produced in a number of countries including India, Thailand, Mayanmar, China, Indonesia, Vietnam and Laos. India and Thailand are the major producers, producing on the average 1700 tonnes of lac annually, followed by China. India alone, accounts for about 70/о of global lac production.
Former Bihar is the most important lac producing state of India. The Indian council of Agriculture Research has established Indian Lac Research Institute at Namkum in Ranchi district of Jharkhand.
The average of different states in the total quantity of stic lac produced in this country is given below:
Total annual global production of pure lac is estimated to be 20,000 tonnes. The average total production of stick lac in India is about 24,000 tonnes, while the annual average pure lac produced in the country is 11,890 tonnes. About 6000 tonnes of pure lac produced in India is exported to different countries of the world, with an average earning of Rs. 202.38 million in term of foreign exchange. It has been estimated that 3-4 million people mostly tribals are engaged in the cultivation and several thousands in addition are engaged in the trade and manufacture of lac.
Two main competitors of Indian lac are (i) Thailac, which accounts 50% of the total lac exported, and (ii) Synthetic resion, which have replaced lac in certain field. Shellac being a versatile resion, there is immense scope of increasing its utilisation in various fields and there is also scope to modify it to meet particular need.
Top 24 Types of Typical Insects (With Diagram) | Animal Kingdom
It is common household pest, usually found in cool damp places, such as among old books, under picture frames, wall papers, clothes, etc. It is wingless. Lepisma does not undergo metamor­phosis. The silver fish commonly feeds on starch, and cause considerable damage to books and clothes.
Insect: Type # 2. Mayflies:
The mayflies are the shortest-lived insects and hardly survive a couple of days.
Insect: Type # 3. Cimex (Bed Bug):
It lives as ectoparasite and sucks human blood so it is sanguivorous. Sometimes, they show cannibalism. The mesothorax is usually hidden by two small wing pads, which are the vestigial fore wings. The hind wings are completely absent. It is supposed that the germs of typhoid, plague, kala-azar, tuberculosis, relapsing fever, etc. can be transferred by them.
Insect: Type # 4. Vespa (Wasp):
They are colonial, polymorphic and social insects, living in the hives. The body is yellowish in colour. They are trimorphic. The workers have a powerful sting by which they can inject into the human body causing pain.
Insect: Type # 5. Aphis (The Aphid):
The aphid sucks plant sap. It excretes ‘honey dew’ through the cornicles (honey dew tubes). The ‘honey dew’, being sweet is eaten by ants. The ants domesticate the aphids for this purpose. Such aphids are called “ant cows”. The female aphids are viviparous and reproduce by parthenogenesis. Aphids are serious pests. They damage the plants by sucking their sap.
Insect: Type # 6. Beetles:
They are mostly pests of crops. The fore-wings are thickened, leathery, hard and opaque, which are called wing covers or elytra. They are not used for flight.
The order Coleoptera in which the beetles are placed, is the largest order in the animal kingdom. Herbivorous beetles feed on vegetables, thus they spoil useful crops. They also spoil stored food grains. Some carnivorous beetles feed on aphids, the harmful insects, therefore, they are useful in this respect.
Insect: Type # 7. Butterflies:
They are diurnal in habit. Pieris (the cabbage butterfly) lays eggs on cabbage leaves. The larvae are worm-like and called caterpillars. They are usually coloured insects. Most of the butterflies are quite destructive, as they feed on crops, orchards, gardens, etc. They are useful in cross pollination.
Insect: Type # 8. Locust:
There are many locusts but Schistocerca gregaria (desert locust) and Locusta migratria (migratory locust) have been known from time immemorial. They are the most destructive of all insects. Locusts come to India from Pakistan. Locusts are serious plant pests.
Insect: Type # 9. Poecilocerus pictus (Ak-grasshopper):
Grasshopper is essentially a solitary insect. Poecilocerus pictus lives on Ak plants. It feeds on leafy vegetation. Therefore, it sometimes causes serious damage to the crops.
Insect: Type # 10. Pediculus (Human louse):
Pediculus humanus is an ectoparasite of human beings and feeds on their blood. Eyes are poorly developed. Wings are absent. They suck the blood and carry germs of typhus fever.
Insect: Type # 11. Xenopsylla (Rat flea):
Xenopsylla cheopis is an ectoparasite of rats and men and feeds on their blood. Wings are absent. Xenopsylla cheopis transmits Bacillus pestis from rat to man which causes bubonic plague.
Insect: Type # 12. Musca (House Fly):
They are saprophagous in diet, viz., taking fluid only. Mandibles are absent. They are very harmful insects because they spread the germs of some dangerous diseases, such as cholera, typhoid, paratyphoid, anthrax, diarrhoea, dysentery, tuberculosis, etc.
Insect: Type # 13. Mosquitoes (Fig. 4.28):
The males generally feed on plants juices, while the females feed on blood. Its saliva contains anticoagulant. There are present piercing and sucking type of mouth parts. Mandibles are absent in male mosquito. The metathorax bears two club-shaped processes known as halteres or balancers.
The pedicel (second segment) of the antenna contains Johnston’s organ which perceives sound vibrations like an auditory Organ (hearing organ). Plasmodium (Malarial Parasite) which causes malaria fever is transmit­ted by the female anopheles.
Filaria which causes filariasis is transmitted by Culex. Encephalitis is caused by a virus in man, which results in high fever, headache, drowsiness and inflammation of the brain. This virus is also transmitted by some species of Culex. Aedes mosquito transmits virus of Dengu fever, Yellow fever and Chikungunya.
Insect: Type # 14. Termites (White ants):
Termites are colonial, polymorphic and social insects. In the colony, mostly two forms are present fertile caste and sterile caste. Fertile castes include the fertile males and females.
Sterile castes include both males and females but are without wings and their reproductive organs are vestigial. Sterile castes include workers, nasutes and soldiers. During the breeding season, the winged male and female fly together which is known as nuptial flight during which copu­lation occurs,
The king fertilizes the queen.
The workers construct and repair the nest (termitarium), collect the food, look after the eggs and feed the nymph and other castes.
They have at the tip of head opening of the frontal gland. The secretion of this gland is sticky in nature and used in the warfare during which it is inflected upon their enemies. This secretion is also used to dissolve hard substances, which workers face during nest formation.
They defend the colony. The main food constituent is cellulose, which they obtained from wood or wood work. They are able to digest cellulose with the help of certain flagellates such as Trichonympha that live in their intestine. The exchange of food between one insect and the other is called tropholaxis which is common in termites.
Insect: Type # 15. Ants:
Like termites they are social, colonial and polymorphic insects. Tropholaxis is common in the ants. Generally male and female go on a nuptial flight. After mating, the males usu­ally die. The mated females shed their wings and lay eggs in the nests.
The main castes of ants are the following:
They are fertile females. They may live up to 15 years in some species,
They are fertile male ants,
Actually they are sterile, wingless females, which are smallest in the nest. The workers take over the feeding of the queen and larvae. They also store the food and build the nests,
They are modified workers bearing large head and powerful serrated mandibles. They protect nest from the enemies. Ants destroy in bulk seeds and grains from fields and godowns. Their useful activities are helpful in pollination, act as scavengers by disposing dead bodies of animals, increase the fertility of soil by burrowing.
Insect: Type # 16. Silk Moth (Bombyx mori):
It is also called mulberry silk moth, which never occurs in the wild state and is a completely domesticated moth. It is called “Resham- Ka- Kira” in Hindi. It is extensively cultivated all over the world. In India, Kashmir, Mysore and Coimbatore are the main silk producing centres. The adults do not feed and survive for two to three days only. They fly very rarely.
The male dies soon after copulation and female after laying eggs. The silk is obtained by killing the pupa inside the hot water. Then, the silk thread is wound. About 1000 metres of silk thread can be obtained from a single cocoon and about one pound of silk can be obtained from 25000 cocoons. Rearing of silk moth for obtaining raw silk is called sericulture. It is done on large scale in China, Japan, Italy, France, Brazil, India, etc.
Insect: Type # 17. Apis (Honey Bee):
Species of Honey bee are:
(1) Apis mellifera — Italian bee,
(2) Apis dorsata— Rock bee – largest,
(4) Apis florea— Little bee – smallest.
Most common Indian honey bee in wild state is Apis indica, however in domestic state the most common Indian honey bee is Apis mellifera (Italian honey bee). Honey bees are colonial, social and polymorphic insects. Unfertilized eggs develop into drones (males) by parthenogenesis. Fertilized eggs develop into queens or workers.
Three types of individuals (castes) are found in the colony of honey bees:
(i) Queen is a fertile female,
(ii) Drones are males. Life span of a drone is 1-2 months,
(iii) Workers are sterile females and perform various duties of the colony. The queens are fed by the workers. The abdomen contains the wax glands and the sting.
The worker bees of a hive fall into three major castes:
(a) Scavenger or Sanitary bees. For the first three days each worker bee acts a scaven­ger.
(b) House or Nurse bees. From the fourth day onwards, each worker bee feeds like a foster mother, with a mixture of honey and pollen.
From the seventh day, the maxillary glands of a worker bee secrete “royal jelly” to feed young larvae, the queen and those older larvae which are destinated to develop into future queens. From the twelfth to the eigh­teenth day, each worker bee develops wax glands. Wax is secreted in the form of thin scales,
(c) Foraging or Field Bees. When a worker bee is about 15 days old, it explores new sources of nectar and pollen and collects these and water. These bees are also called scout bees. Ernest Spytzner (1788) was the first to draw attention to the fact that bees communicate by means of definite movements now called “bee dances”.
Prof Karl von Frisch decoded the language of “bee dances” and got Nobel Prize in medicine or physiology for it in 1973. He discovered that scout bees perform two types of dances for communica­tion.
(i) Round dance is performed when a newly discovered food source is close (less than 75 metres) to the hive
(ii) Tail wagging dance is performed for long distance sources. Life­span of a worker honey bee is 3-4 months.
(i) Honey bees provide honey. Honey is a natural valuable tonic for human body. It contains enzymes, vitamins, monosaccharide sugars mainly glucose and fructose, pigments, ash, moisture, minerals and so on. Honey has neutral ph. Honey also acts as antiseptic,
(ii) Bee wax is used in making candles, polishes, toilet goods, cosmetics, electric goods, carbon paper, etc.
(iii) Honey bees help in the pollination of flowers of fruit plants and seed crops,
(iv) Their sting is poisonous and sometimes fatal to man when they attack in large numbers.
Rearing of honey bees to obtain honey and bee wax is called apiculture. A place where bees are kept is known as apiary. A person who keeps bees is called apiarist.
Insect: Type # 18. Laccifer (Tachardia) lacca— Lac Insect:
It is found in thick forest in India, Myanmar (Burma), Ceylon (Sri Lanka), Thailand, Philippine Island, Formosa and East Indies. The females are degenerate individuals, without wings, legs and eyes. The body of the female is soft, ovoid and without segmentation. It has at the anterior end a 2-jointed rostrum and 2- short processes bearing a pair of spiracles.
Male has a segmented body divisible into head, thorax and abdomen. The abdomen bears at its end a pair of long anal hair. There is sexual reproduction. The females can also reproduce parthenogenetically. The males are active and females are motionless.
During unfavorable season, the females secrete lac to form protective nest for egg laying upon branches of Peepal, Dhak, Bargad and other trees. Nymphs, not larvae, hatch- out from the eggs. Lac is scraped from the surface of trees, crushed and sieved to produce lac dust.
It is used in the manufacture of shellac, varnish, polish, buttons, bangles, toys and some electrical items. A dye is prepared from dead and dried bodies of the females. This dye is used by women folk of our country for mahavar. India is the major lac producing country.
Insect: Type # 19. Sympetrum (Dragon Fly):
The dragon flies are mostly found in the vicinity of water. They are also called the “mosquito hawks” as their main diet is mosquitoes. Thus, they help in controlling malaria. The female lays eggs in the water.
The naiads are stout, and their rectum is elongated to form a rectal respiratory chamber in which the gaseous exchange takes place. In the rectal chamber, the naiad draws water and then expels out. This is an unusual structure, which occurs in naiads of dragon fly only.
Insect: Type # 20. Mantis (Praying mantis):
Praying mantis is usually found on the leafy vegetables, where it feeds on other insects which it captures by means of their prehensile fore-legs. Canni­balism is very common in these insects. Praying mantis destroys certain harmful insects, so it is a useful insect.
Insect: Type # 21. Palamneus (Scorpion):
It is viviparous. The body is divisible into (i) anterior the prosoma and (ii) posterior the opisthosoma.
It is un-segmented and covered by a carapace. The latter bears a pair of large median eyes and two groups of smaller lateral simple eyes, each group comprise three eyes. Ventrally the prosoma has a sternal plate and six pairs of appendages, i.e., one pair of small chalicerae, one pair pedipalpi and four pairs of walking legs.
It is differentiated into anterior mesosoma and posterior metasoma.
It is made of seven segments. The sternum of the second segment bears a pair of comb-like sensory appendages, the pectines. The sternum of each of 3rd, 4th, 5th and 6th mesosomal segments bears a pair of oblique slit like openings the stigmata, which lead into respiratory organs, the book lungs,
Its posterior narrow part consists of five segments. The last segment bears the anus and a stinging apparatus or telson. The latter consists of a swollen base, the vesicle or ampulla and a curved and pointed spine, the aculeus. Inside the vesicle lies a pair of poison glands, the ducts of which open by a pair of minute apertures at the tip of the spine.
Insect: Type # 22. Aranea (Spider):
The body is divisible into an anterior cephalothorax and a posterior abdomen. The cephalothorax has six pairs of appendages (one pair of chelicerae, one pair of pedipalpi and four pairs of walking legs).
The abdomen is un-segmented, rounded and without telson but has three pairs of spinnerets or spinning organs which produce threads for the construction of spider web. Book lungs and the tracheae are the respiratory organs. Excretory product of spider is guanine. Poisonous spider is Lectodectus meactans.
Insect: Type # 23. Sarcoptes (Mite):
Sarcoptes scabiei is a dangerous ectoparasite which attacks man, causing scabies, producing severe irritation. Anterior two pairs of legs are stronger. Posterior two pairs of legs are shorter and attached more ventrally and carry long bristles.
Insect: Type # 24. Ixodes. (Sheep Tick):
The body is covered with leathery skin and is without segmenta­tion. Four pairs of legs are segmented. The tarsus of first pair of legs has a sensory cup shaped Haller’s organ. Respiration is by spiracles and tracheae. It has blood sucking mouth parts. Its saliva contains an anticoagulant which prevents coagulation of blood. It feeds on the blood of sheep.
Top 22 Insect Species Found in India
List of twenty-two important insects species found in India:- 1. Silver Fish 2. Springtail 3. Locust 4. Rice Bug 5. Cricket 6. Stick and Leaf Insects 7. Earwig 8. Mayfly 9. Dragon Fly 10. Bed Bug 11. Louse 12. Lac Insect 13. Butterfly 14. Common Windmill (Parities Philoxenus) 15. Krishna Peacock (Papilio Krishna) 16. Kaiser-I-Hind (Teinopalpus Imperialis) and Others.
1. Silver Fish:
These insects, Lepisma saccharina (Fig. 18.94A) are commonly seen in cupboards and book-racks, where they devour starchy products. The body is small, flat and silver- coloured. The mouth parts are adapted for chewing. The compound eyes are insignifi­cant. In the exoskeletal covering, the ventral sternites are not covered by dorsal tergites. The thorax is distinct and the prothorax forms the largest segment of the body.
The abdomen has ten segments. The eighth and ninth segments bear small appendages. The last abdominal segment carries at the poste­rior end a pair of long, many-jointed cerci and a long tail in between.
The entire body is covered by shining scales. The excrement products are in the form of dry pellets. The heart hangs from the dorsal body wall by means of threads. The adults can moult and possess regenerating power.
These are small, soft and wingless insects (Fig. 18.94B), which live under fallen leaves, decaying vegetation and beneath the piles of logs and woods. The well-known genera are Bourletiella, Isotonia and Nearura. Each an­tenna is made up of 4-6 segments and the antennae are responsible for perceiving warmth.
These insects prefer moist places and such moist conditions are sought by determining the humidity of both ground and air. The compound eyes are absent but eight identical simple eyes are present on each side. The mouth parts are mostly of chewing type.
The abdomen has six seg­ments and is provided at the terminal end with anal fork or furcula. This furcula re­mains engaged in the ventral side of the fourth abdominal segment, called hemmule.
When the furcula attempts to extend, it slips out from the catch of the abdominal segment and throws the insect into the air. Luminiscent organs are seen in many and fat body serves as the source of light.
Malpighian tubules are absent and its excretory function is carried by special glands which open above the base of the labium through a common duct. The fat body contains a special kind of cells, called urate cells, which collect uric acid crystals.
The males release hundreds of spermatophores. Each spermatophore re­mains attached on the surface by a thin hyaline stalk. When these spermatophores get in touch with the moist vulva of the female they burst open to release the sperms.
Some sperms enter within the body through the female genital opening and fertilize the eggs. A pit in the anterior dorsal region of the embryo contains a peculiar filamentous dor­sal organ which always absorbs water.
The term locust includes gregarious and migratory grasshopper-like forms. Large head with prominent eyes is curved down­wards and incompletely concealed by prothorax. Each lateral side of the first ab­dominal segment carries a tympanum. In females, the ovipositor is made up of small plates. Some common species of locusts are: Locusta migratoria, Schistocerca gregaria, Pachytylus cinerascens.
The locusts have two phases in their life—solitary and migratory (Fig. 18.94C & D). The migratory phase appears due to some unknown reason and just before migration the population increases rapidly. The swarms move like a cloud and the direction is guided by the flow of wind.
The swarms of locusts damage plant popu­lation severely in course of their journey. The swarming does not occur each year. The wingless young locusts also migrate by hop­ping. Usually they moult five times. At the end of fourth moult the instar is sexually active but the fertility is reached only after the fifth moult.
4. Rice Bug:
The rice bug (Leptocorisa varicornis), com­monly known as Gundhi bug, is a Hemipteran insect causing serious damage to paddy crop. It has a typical hemipteran body plan with sucking type of mouth parts.
This insect emits an unpleasant odour from the abdominal scent gland, so the name Gandhi bug for the insect. The milk stage of the paddy grain is its main target. The rice bug sucks out the milky juice and leaves only the white chaffy husks. In case of severe infec­tion all the paddy grains become chaffy.
The pests breed amidst wild grasses in uncultivated areas near paddy fields. When the rice is advancing in milk-grain stage, the adult insects invest the cultivated areas. An adult insect has a slender body with a length of about 15 mm.
The anterior pair of the wings is tough and thick while the posterior pair is membranous in nature. The insect is greenish in young stage which turns into a mixture of green and brown in adult which finally turns into brown in old stage.
Females lay small blackish-brown bead­like eggs. The rounded eggs remain arranged in linear fashion on the ventral surface near the midrib of leaf blades of the host plants. The eggs require about a week’s time to hatch. The resultant nymphs, immediately after emergence, start sucking the plant juice and develop into adults within two to three weeks’ time.
Routine-wise schedule as preventive measures:
(i) Selection of paddy-growing areas free from wild grasses which are the host plants on which the rice bug inhabits.
(ii) To clear off paddy stubbles by plough­ing or by burning and scrapping of bunds as a regular routine.
(iii) Step up of light traps can be used in field with contact insecticide near paddy field to attract adult pest dur­ing milky stage of paddy grain.
(iv) Regular check-up of egg masses on paddy field and immediate step is advisable if egg masses are noticed.
(i) Contact insecticide—5% BHC spray or dust on crops and bunds.
(ii) Paddy field is to be flooded with water and then insecticide along with oil emulsion is to be applied. Nicotine sulphate, lubricating oil emulsion, kerosine emulsion or lime sulphur solution are generally used.
These solitary insects (Acheta, Gryllus) live in warm places. The paired antennae are long (Fig. 18.94E). The elongated ovipositor is spear-shaped. The sound producing stridulating apparatus consists of a scraper in the base of one wing and a file on the base of other wing.
As the wings vibrate rapidly the file rubs over the scraper to produce the characteristic chirping sound. A kind of cricket, called the mole cricket, Gryllotalpa (Fig. 18.91F) has stout and clawed prothoracic legs for the purpose of digging.
6. Stick and Leaf Insects:
These insects have perfectly copied the structures of branches and leaves of the trees (Fig. 18.94G & H). Such mimicry protects them from enemies. The females exhibit more accurate mimicry than males. In general these large-sized herbivorous insects are provided with distinct eyes and multi-jointed anten­nae. The stick insects (Diapheromera, Carusius) may be 30 cm in length.
The mesothorax is the largest segment. The legs and other parts of the body assume branch-like appearance. Similarly in leaf insect (Phyllium), the wings and other parts of the body extend to be leaf-­like. The eggs resemble the appearance of seeds and newly hatched young’s also exhibit mimicing features. It gradually increases in size with each moulting.
These insects (Forficula auricularia) (Fig. 18.94 I & J) are usually nocturnal and car­nivorous. The terminal part of the abdomi­nal appendages is forceps-like. The mouth parts are built for chewing. The fore-wings are small and the hind-wings are large. The females brood over the eggs.
The mayflies, Ephemera (Fig. 18.95A), are noted for two unique features:
(i) Winged adult stage has a life span of one day and
(ii) Moulting occurs in a winged form.
The adult aerial form has two pairs of unequal membranous and triangular wings. The abdomen ends in long cerci which may or may not have median terminal filaments. The adult dances in air and lay eggs in water.
The development continues almost for a year and involves twenty-three moultings before the emergence of adult state. The aquatic larvae are free-swimming and possess rows of tra­cheal gills on each side of the abdomen for respiration. Finally, they break the nymph wall and come on land to rest in some places like trees or walls. Another moulting of this winged form liberates the full-grown adult.
9. Dragon Fly:
These are usually large-sized insects. The common genera are Macromia, Aeschea, etc. It is provided with chewing mouth parts and membranous wings. Sometimes the hind- wings are larger than the fore-wings. At the time of rest, the wings are held horizontally (Fig. 18.95B). The compound eyes are quite prominent but the antennae are short. The abdomen is elongated, slender and thread­like.
The dragon flies are predators and hunt other insects like a kite. The mating takes place during flight and the eggs are released in water. The larvae, called nymphs, are aquatic and respire through a special kind of aquatic gills. The elongated labium is provided with hooks and remains folded during rest. It is extended rapidly during food capture.
10. Bed Bug:
These sanguivorous ectoparasites live in close association with man and are cosmo­politan in distribution. Number of diseases, i.e., anthrax, leprosy paratyphoid, oriental sore is believed to be caused by bed bug (Cimex lectularius, Cirotundatus).
The beddings, furni­ture and crevices of the room are the favourite abode of these insects. The warmth as well as the smell of the host attracts them and the bed bugs are active specially during night.
The adults (Fig. 18.95C) are 4-5 man in length and 3 mm in breadth and are reddish brown in colour. Flat and oval body is pro­fusely covered with bristles and hairs, short head distinct paired compound eyes and a pair of four-jointed antennae. The mouth parts are adapted for piercing and sucking. For that purpose, the mouth parts have formed a proboscis which encloses needle­-like maxillae and mandibles.
When not in use the proboscis is kept folded on the ven­tral side of the body. The prothorax is semi­lunar and the mesothorax is triangular. The pointed end of the mesothorax is directed backwards and it bears atrophied first pair of wings. There is no trace of second pair of wings. The abdomen is flat and contains eight distinct segments.
In males, the abdo­men is more pointed. A curved penis is lodged in a deep groove in the left side of the eighth abdominal segment. The stomach serves as a crop and stores blood during meal. This blood may be retained for several weeks. The saliva, which mixes with the blood meal, contains anti-coagulating en­zymes which keep the blood liquid.
The digestion takes place in the intestine. The first part of the midgut is formed by vacu­olated cells and is concerned with the ab­sorption of fluid from the meal. Only a little haematin material passes within the hind­gut. The blood cells or haemocytes of bed bug do not enter within the cavity of the heart.
The haemocytes remove debris from haemolymph at the time of moulting. It can live for weeks without food and water. Lack of water leads to the formation of dry yellow urine. The inner surface of sternum in mesothorax carries paired stink glands, which produce characteristic smell of the bed bug. The secretions of these glands are transparent, oily, volatile and strongly acidic.
The secretions are released through a pair of median apertures. The stink glands of nymph stage are abdominal in position and three in number. In the adult stage, these glands atrophy and new thoracic glands appear. The genital segment of male, at the posterior end of the abdomen, is provided with a pointed clasper (Fig. 18.95D).
During copulation, the sperm cells are deposited in a pouch on the lower surface of the female abdomen. These cells reach the genital tract after travelling through the gen­eral body cavity. Most of the eggs are ferti­lized, when still in the ovary. The eggs when laid are glued to the substratum by a mucilagenous coating.
The young hatches out by lifting a lid on the egg, called oper­culum. The metamorphosis is incomplete and the young is called nymph. Such nymphs are yellowish white and 1.5 mm in length. The growth and conversion to adult struc­ture involve five moults. Nymphs are also able to suck blood and it is believed that the distension of the abdomen of nymph due to blood meal causes moulting.
Three kinds of lice are seen—Book-lice (Fig. 18.96A), Biting lice (Fig. 18.96D) and Sucking lice (Figs. 18.96B & C).
The book-lice include numerous kinds of species. These are minute, insignificant and soft-bodied insects having peculiarly modified biting mouth parts. Though they are called book-lice, majority of them live on trees and only a few live within old papers. Two pairs of wings are membranous and have characteristic pattern of venation. At the time of rest the wings are held roof-like over the abdomen.
The biting lice include more than 2500 species, all of which live as ectoparasites on birds and mammals. The body is flat and covered with bristles. The wings and com­pound eyes are absent.
The mouth parts are adapted for biting but much reduced. Food usually includes the feathers or hairs of the hosts but some are blood-suckers. Eggs are glued with the feathers or hairs of the host and the larvae are also ectoparasites. Devel­opment involves three moultings.
The sucking lice are exclusively ectoparasitic. All are blood-suckers and for that purpose the mouth parts include thin stylets within a cephalic sac. The wings and eyes are absent. All the thoracic legs have well-developed claws. The human head and body louse is known as Pediculus humanus.
12. Lac Insect:
The lac insects are scientifically known as Tachardia lacca. Previously, the genus Tachardia was known as Kerria. Two species under the genus are very common—K. lacca and K. chinenses. Of the species, Kerria (Tachardia) lacca is the common Indian variety. India is the highest lac-producing country.
Thailand comes next to India regarding lac production. These insects live on certain specific trees like kusum, khair and ber (kul). It liberates a resinous product as exudate which forms a crust around the insect. From this exudate a product, called lac, is obtained.
Thus, lac is regarded as resinous secretions produced by the female members of the lac insect. In order to obtain lac, these insects are cultured and the technique of lac production is called lac culture. It involves proper care of host plants, regular p running of the host plants, propaga­tion of insects and collection and processing of lac.
For the purpose of propagation the older branches (approximately 23-30 cm) containing crusts are tied with new branches and this method is called inoculation. When new crusts are formed, most are collected and this collection is known as harvesting.
According to its harvesting season, the lacs are classified into two types:
It grows on kusum trees and is inoculated in January-February and harvested in June and July of the following year.
It grows on other trees excepting kusum. The inoculation time is October-November and harvesting time is May-June. The kusum trees being much larger in size, provides more surface area and thus the yield of Kusmi lac is higher than the Ranjeeni lac.
After inoculation, lac insects come out of the old crusts. At this stage they are known as nymphs, which have hatched out from the eggs, laid by the females in the old crusts.
When nymphs vacate the old crust, the crust is called Phunki. The phunki must be re­moved within three weeks from the date of inoculation otherwise it will be susceptible to parasitic infection. The coming out of nymphs from older crust is called swarming.
These nymphs are boat-shaped and reddish in colour. Each nymph possesses three pairs of thoracic legs, one pair of antennae and a pair of caudal setae. Some of the nymphs become winged or wingless male and others become female (Fig. 18.97). These nymphs explore new branches. It sucks cell sap by piercing the branches with the help of spe­cialised maxillae and mandibles.
The nymph settles in a suitable spot and liberates a kind of exudate. The nymphs gradually lose most of its body structures and undergo repeated moulting. The thrown-out skin together with the exudate forms a crust around it. Each crust contains a pair of branchial pores for respiration and a big anal tubercular open­ing. In male, the tubercular opening is pro­vided with an operculum.
After three moultings the males come out by removing the operculum and copulate with the female. The males are devoid of mouth parts, for this reason they die soon after copulation.
Most of these crusts are removed at the time of harvesting and are used for extracting lac. As the males are short-lived, they produce lesser lac than the female. The production of lac is good, if the ratio of male and female remains 30: 70. If number of male increase in a par­ticular year, the crop is said to be poor.
Extraction of lac:
The mature incrusted twig is cut. Then the incrustations are washed thoroughly and scraped to remove the secreted materials. These materials constitute the granular lac which is dried and bleached in the sun. The granules are taken in suitable pot and heated by open charcoal fire.
During heating the lac is forced out as it melts. Pigments can be used as dyes at this stage. In molten condition, these materials are stretched into sheets. After drying, these sheets are broken into flakes.
Lac has great commercial value. It is extensively used in the manufacture of:
(ii) Varnishes and polishes,
(iv) Electrical insulating material,
(v) Shoe polishes toys ornaments, etc.
For their colourful texture and elegant movement, these daytime flying insects are regarded as the symbol of grace, beauty and austerity. The head bears two large com­pound eyes, each with numerous ommatidia.
A pair of club-shaped antennae characterise the butterfly. The butterflies have two pairs of large wings which at the time of rest are held high over the body, like sails of a boat. The equal-sized wings are provided with hairs and scales.
The sucking type mouth parts are formed by a long-coiled proboscis. It is formed by the union of two halves of a tube each half represents the outer part of maxilla. The pro­boscis remains coiled when not in use, under the head and extends during use. The man­dibles are insignificant. Labium is absent but the labial palp is well extended. Each type of butterfly has preference for a particular plant to lay eggs.
The larva after hatching out of egg often eats voraciously. The larvae, which are called the caterpillars (Fig. 18.98), have powerful mandibles, three pairs of jointed thoracic legs and four to five pairs of un-jointed ab­dominal legs. The growth of caterpillar in­volves the shedding of old cuticle. Within a fortnight the caterpillar sheds its skin repeat­edly and becomes full-grown.
After certain period of growth the caterpillar produces around its body a covering and becomes sedentaric pupa. The secretion is produced by special silk glands which are present in the body of caterpillar. The pupa is also known as chrysalis and it possesses a slen­der stalk. Rapid transformation of body parts occur within pupa.
Various caterpillar struc­tures are then replaced by the appearance of adult parts. On completion of the develop­ment, the butterfly emerges by breaking the pupal case. Immediately after coming out, the body remains soft. Following butterflies are well-known in our country.
14. Common Windmill (Parities Philoxenus):
These beautiful velvety black coloured butterflies (Fig. 18.99A) are found in the Himalayan region specially in Assam. The size is 11 to 15 cm across. The anterior wings are smooth in outline but posterior wings are peculiarly notched. The posterior wings are also marked by beautiful red spots.
15. Krishna Peacock (Papilio Krishna):
These large butterflies (Fig. 18.99B) with wingspan of 10 cm have beautiful green texture with red, yellow and blue markings. They are quite common in the Himalayan region, specially in Sikim and Bhutan. The posterior wings are peculiarly lobed.
16. Kaiser-I-Hind (Teinopalpus Imperialis):
These rare butterflies (Fig. 18.99C) of Assam, Nepal and Sikim exhibit sexual dimorphism. Males have a single tail but females have three. They generally live on the top of the tree and on rare occasions come to the ground.
17. Rice Butterfly (Melanitis Ismene):
These deep brown coloured, shade-loving butterflies (Fig. 18.99D) are quite common in India. They lay eggs on paddy plants and have characteristic coloured eye spots at the centre of the wings. The caterpillars are green.
18. Cabbage Butterfly (Pieris Brassicae):
These white, yellow or organge-coloured butterflies (Fig. 18.99E) are often seen in agricultural fields. They lay eggs on cabbage and other plants under Cruciferae, and pupa remains in upright position. These are mi­gratory in nature.
These are insects with hard integument and chewing mouth parts. The prothorax is large and movable. The stiff and hard anterior wings, known as elytra, cover the posterior wings completely. Some are wingless. It exhibits complete metamorpho­sis and larvae are provided with well-developed head, biting mouth parts and three pairs of legs.
Following beetles are very interesting:
These oval bod­ied beetles (Fig. 18.100A) are provided with short antennae and small legs. It lives upon leaves of various plants like potato, cucum­ber, etc.
Eleven segmented antennae of these beetles (Fig. 18.100B) are longer than the body. Larvae are wood-borers.
These small, more or less round beetles (Fig. 18.100C) are noted for their habit of feigning death. These beetles are commonly seen in the fur of museum specimens, carpets, woolen dresses and in different other domestic goods. Its abdomen remains fully enclosed by the elytra. The well-known examples are Anthrenus, Dermestes.
These beneficial insects (Fig. 18.100D) destroy aphids and other plant pests. They have beautiful red-coloured bodies with black spots on it. They are distributed throughout the world.
These large aquatic beetles are seen throughout the world in fresh-water ponds, lakes and pools. Their food includes small fishes, aquatic insects and other small aquatic organisms. The adults have thread-like antennae, oar-shaped hind legs, and they can fly well.
While diving inside water they carry a film of air beneath their wings. The large-sized whirligig beetle (Fig. 18.100E) at the time of diving carries a bubble of air at the posterior end of the body. The larvae possess strong mandibles and long abdomen.
These beetles (see Fig. 8.10B) are well known for their ability to emit light. For this purpose, they possess phosphorescent organs which are present in the posterio-ventral aspect of the abdominal segments and are in connection -With traches. A substance luciferin is present in this organ, which is oxidised in the pres­ence of an enzyme luciferase to produce light in them which is without heat.
These beetles have peculiar elongated head which is drawn to form a rostrum. These are highly injurious to plants, fruits, seeds and stored grains. The well-known examples are—rice weevil (Calandra oryzae), mango weevil (Apion sp.).
They are also known as scrab beetle and were considered sacred in ancient Egypt. They are well-known for their parental care. They pre­pare small spheres by rolling dung, and eggs are laid on them by the females. These balls are deposited in a hole. When the grub comes out it uses the dung as food.
Two kinds of wasps are well- known—Spider wasps and Hornets. The spider wasps are large, active, long-legged and hunt spiders. These wasps build under­ground burrows and place a paralysed spi­der within it. One egg is laid on each spider. When the larva hatches out, it eats the spider.
The hornets live on nectar, ripe fruit, sugary fluid and also eat larvae and small insects. Some are solitary but many exhibit highly organised social life. A family in­cludes queen, males and workers.
After copu­lation, the queen hibernates for a year and then starts to lay eggs. First lot of eggs develops into workers, and then queens and males emerge. Its nest is papery and has several tiers and the entire nest is enclosed within an outer envelope.
Ants are well-known example of the insects which exhibit polymorphism. Like termites and bees, they also lead a social life.
There exist innumerable types of ants (nearly 3,500 species) which abode various places from burrows to specially formed nests. In ants the abdomen is distinctly sepa­rated from thorax, and antenna is divided into an un-jointed basal part and a many-jointed upper part.
Colony of ants includes following forms:
Only the males and the females possess transparent wings and enter into nuptial flight. At the end, they lose their wings and the female lays eggs. From each egg an elongated legless grub is developed which transforms into pupa. These pupae develop into workers (Ergates) which start to take care of the nest. As in bee the unfertilized eggs produce males, and fertilized eggs give rise to workers and females.
The workers are wingless and possess female gonads in ar­rested state of development. Some workers undergo special modification in their struc­tures to act as soldiers. The workers do all sorts of work and the males and the females are dependent on them.
The job of the work­ers includes collection of food, protection of the nest, rearing of grubs and pupa, cleaning of the nest. It has now been determined that a substance, called pheromone, guides the foraging workers to identify the way to its own nest.
Some ants are known to rear insects like beetles, aphids in their nests. Specially these aphids when touched by the antennae of ant secrete a juice and for this reason they are known as ant-cow. The sol­diers are modified workers which are de­void of wings but possess large heads and powerful mandibles. Their role is to protect the colony from the enemies.
The well-known ants (Figs. 18.101B & C) are common red ant (Oecophyla smaragdyna), black ant (Componotus compressus), European wood ant (Formica rufa), etc. Ants often destroy vegetations but at the same time they are effective pollinat­ing agents. Several ants kill caterpillars, bugs and beetles and thus serve as important agent for biological control.
These insects in their adult stage live as ectoparasites on birds and mammals. Nearly 1500 species are known. The body is laterally compressed, brown and strongly sclerotised (Fig. 18.101D). The head is small and the mouth parts are adapted for piercing and sucking. All are sanguinivorous. The wings are absent, but the legs are well devel­oped and specially the hind legs are adapted for leaping.
A female flea lays nearly 300-500 eggs. The larvae are white, small and worm­like. The head of the larva carries a spine, which breaks open the egg shell at the time of hatching. The larva is free-living. The next stage pupa covers itself with a silken cocoon, impregnated with sand grains and debrises.
The most notable flea is rat flea (Xenopsylla cheopis) which carries a bacterium (Pastaurella pestis) from infected rats and causes Bubonic plague in man. The same flea also infects another disease, called endemic typhus. The other important fleas are Pulex irritans (human flea), Ctenocephalides felis (cat flea) and Ctenocephalides canis (dog flea).
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Cricket, (family Gryllidae), any of approximately 2,400 species of leaping insects (order Orthoptera) that are worldwide in distribution and known for the musical chirping of the male. Crickets vary in length from 3 to 50 mm (0.12 to 2 inches). They have thin antennae, hind legs modified for jumping, three-jointed tarsal (foot) segments, and two slender abdominal sensory appendages (called cerci). The two forewings are stiff and leathery, and the two long, membranous hind wings are used in flying.
Male crickets produce musical chirping sounds by rubbing a scraper located on one forewing along a row of about 50 to 250 teeth on the opposite forewing. The frequency of the chirps depends on the number of teeth struck per second and varies from 1,500 cycles per second in the largest cricket species to nearly 10,000 cycles per second in the smallest. The most common cricket songs are the calling song, which attracts the female the courtship, or mating, song, which induces the female to copulate and the fighting chirp, which repels other males. Both sexes have highly sensitive organs on the forelegs for sound reception. There is a direct relationship between the rate of cricket chirps and temperature, with the rate increasing with increasing temperature.
Most female crickets insert eggs into soil or plant stems with their long, slender ovipositors, sometimes causing serious plant damage. In northern latitudes most crickets mature and lay eggs in the fall. The nymphs hatch in the spring and become adults after 6 to 12 molts adults ordinarily live 6 to 8 weeks.
The field cricket (genus Gryllus) and the house cricket (Acheta, formerly Gryllus, domesticus) of the subfamily Gryllinae are stout-bodied and black or brown and often dig shallow burrows. They may feed on plants, animals, clothes, and each other. The field cricket (also called the black cricket) is common in fields and yards and sometimes enters buildings. The house cricket, introduced into North America from Europe, has a light-coloured head with dark cross bands and may be found in buildings and refuse heaps. Widely distributed, house and field crickets chirp day and night. They are used as fish bait in some countries and are also used in biology laboratories. Gryllus is often referred to in poetry and prose.
Ground crickets (subfamily Nemobiinae, or sometimes Gryllinae), approximately 12 mm long, are commonly found in pastures and wooded areas. Their song is a series of soft, high-pitched trills. The striped ground cricket (Nemobius vittatus) has three dark stripes on its abdomen.
Tree crickets (subfamily Oecanthinae) are white or green in colour and have transparent wings. Although tree crickets are beneficial to humans because they prey on aphids, the female injures twigs during egg placement. The song of most tree crickets is a long trill. The snowy tree cricket (Oecanthus fultoni) is popularly known as the thermometer cricket because the approximate temperature (Fahrenheit) can be estimated by counting the number of chirps in 15 seconds and adding 40. Tree- and bush-inhabiting crickets usually sing at night, whereas weed-inhabiting crickets sing both day and night.
Ant-loving crickets (subfamily Myrmecophilinae) are minute (3 to 5 mm long), wingless, and humpbacked. They live in ant nests. Wingless bush crickets (subfamily Mogoplistinae) are generally found on bushes or under debris in sandy tropical areas near water. They are slender crickets, 5 to 13 mm long, wingless or with small wings, and are covered with translucent scales that rub off easily. Sword-bearing, or winged bush, crickets (subfamily Trigonidiinae) are 4 to 9 mm long and brown and possess a sword-shaped ovipositor. They are characteristically found in bushes near a pond.
Crickets play a large role in myth and superstition. Their presence is equated with good fortune and intelligence harming a cricket supposedly causes misfortune. In East Asia male crickets are caged for their songs, and cricket fighting has been a favourite sport in China for hundreds of years.
Insects called crickets but not of the cricket family Gryllidae include the camel cricket, Jerusalem cricket, mole cricket, and pygmy sand cricket.
This article was most recently revised and updated by Alison Eldridge, Digital Content Manager.
Major Insects Pests that attack Guava Trees in India and their Control
Guava (Psidium guajava) is a common fruit of Indian sub-content. It is a native of tropical America. In India, it was introduced in 17th century and is now a household fruit especially in Uttar Pradesh and Bihar.
The fruit is eaten in its raw form. Immature fruits are not edible however mature and ripe fruits are relished by people of different age groups. Guava juice is used for making jam, jelly, fruit butter and sugar syrup.
Through grafting and hybridization different varieties of guava have been developed. Guava trees are hardy as it can withstand draught and tolerate varying soil conditions. Guava contains fair amount of carbohydrate phosphorus, calcium and iron. The fruit is very rich in vitamin С and vitamin A. More than 80 species of insects have been observed which, in one form or another, affect the quality and yield of guava however few of them cause serious damage.
1. Dacus (= bactrocera) dorsalis hendel:
Dacus dorsalis is a major pest of guava and mango. It also infests brinjal chillies, apricot, sapota, ber etc. This pest is found all over India.
Both adult and maggote cause damage to the fruit. The maggots destroy the pulp which in turn becomes discoloured and produce foul smell. Brown rotten patches appear on the attacked fruit which eventually falls down. Adult feeds on exudations of ripe fruit. The puncture produce by female on the surface of fruit for egg laying makes way for the micro­organisms to enter inside the fruit.
Marks of Identification:
The insect is light brown with transparent wings and yellow legs. 1 he fruit fly is little larger than the house fly and is stoutly build.
Female laid eggs on the soft skin of the ripening fruits. The eggs are inserted under the rind of the fruits. The adult flies emerge out in the month of April and starts laying eggs. The process of egg lying continues for about four months i.e., till July. The eggs are laid in clusters of 2 – 15 on the host fruits. During the adult span of four months a female laid 600 to 800 eggs.
The maggots that emerge from the eggs feed on the ripe pulp of the fruit. Larval life lasts for 6-44 days. The mature maggote comes out of the fruit and drop on the ground to form pupa. Pupa formation occurs 4 to 6 inches below the surface in the soil. Pupal life lasts for 6-29 days. Adult emerges out from the pupal case. They are good fliers.
1. The fallen and infested fruits should be collected and buried deep into the soil.
2. Ploughing around trees to expose pupa to be destroyed by heat and predators.
1. The adult flies may be trapped and killed by poison baiting or bait spray (20 ml malathion + 200 g molasses in 20 liters of water)
2. The hedges around the guava trees may be sprayed with endosulfan (0.1%), carbaryl (0.1%) or Quinalphos (0.05%).
2. Indarbela tetraonis moore:
(Bark Eating Caterpillars/The Shoot and Bark Borer)
It is a common pest of guava and is widely distributed all over the Indian sub­continent. Although, this pest is found in several parts of India like Bihar, Orissa, Haryana, Rajasthan, Madhya Pradesh, Maharashtra, Andhra Pradesh and Tamil Nadu, it is more common and destructive on guava trees especially in Punjab, Uttar Pradesh and South India.
Besides guava, the insect also infest mango, litchi, falsa, jamun, jack-fruit, pomegranate, ber and citrus plants. Damage is caused by the caterpillars. The caterpillar bore into the bark and stem as deep as 15 to 25 сm and feed on bark tissues. The conducting tissues are destroyed affecting the growth of the tree and fruit yield.
The caterpillar remains hidden in the bore hole during daytime. At night, it comes out and feed on the bark of the tree. The larva covers the bore hole and surrounding area by silken web, which provides protection and shelter to the pest while feeding. A single larva inhabits a bore hole however there may be 15 to 30 larvae in a single tree. Holes on the stem surface and silken galleries full of faecal matter and frass indicates the presence of the pest.
Marks of Identification:
The adult insect is short, stout pale-brown moth. The fore wings bear deep brown vertical markings while the hind wings are greyish-white. The wing span is 46 to 50 mm in case of female and 35 to 38 mm in case of male.
Egg lying commences from April to June. Female laid eggs in cuts and crevices in the bark of the host tree in clusters of 15 to 25. In 8 to 10 days larvae hatches out of eggs.
For sometimes the larva feed on the bark. They form a ribbion chips and produce silken threads on the bark surface. The more advanced larva bore into the wood making short tunnels in the stem. During daytime the larva remain inside tunnel but in night comes out to feed on the bark.
A fully grown larva is dirty brown in colour and measure 38 to 45 mm in length. The larval life lasts for 10 to 11 months. After that the larva pupate inside the galleries during March — April. Pupal period lasts for 15 to 25 days. Adult emerges out from pupa. There is a single generation in a year.
1. The frass and faecal matters along with ribbon like silken web should be scrapped from the bark and bum, so that caterpillars hidden under them are destroyed.
2. Hot water may be inserted in the bore hole through syringe.
1. After removing frass and faecal matter from tree bark, 0.1% emulsion of quinalphos or 0. 05% chlorpyriphos should be sprayed.
2. Injection of enderin (0.04%) or BHC (0.2%) or DDT (0.5%) and endosulfan (0.05%) into the hole can kill the larva present inside the stem.
3. Cotton wool soaked in carbondisulphide, chloroform or petrol should be inserted into the holes on tree bark. The opening of the hole may then be covered with mud.
5 Major Disease Producing Insects
Several species of Anopheles are vectors of human malaria. The female Anopheles bites a malarial patient and takes in malarial Plasmodium along with human blood. Plasmodium multiplies and undergoes sporogony in Anopheles which transmits the parasite when it bites another person.
There are four types of malaria:
1. Plasmodium vivax causes benign tertian malaria in which the attacks of fever are every 48 hours.
2. P. malariae causes quartan malaria in which fever comes on every 72 hours.
3. P. falciparum causes malignant tertian malaria in which fever is more or less continuous.
4. P. ovale causes mild tertian malaria in which fever comes on every 48 hours. Because different species of Anopheles are widely distributed, malaria is very widespread. Malaria not only causes thousands of deaths annually in the tropics, but it also prevents the cultivation of the most fertile regions of the earth.
Culex transmits malaria in birds. Culex fatigans and C. pipiens are intermediate hosts and vectors of the larva of a nematode Wuchereria bancrofti whose adults cause elephantiasis in man. The larvae of Wuchereria come to the peripheral blood only at night when the Culex sucks blood and takes in the larvae.
The larvae develop in the mosquito and are transmitted to new human hosts where they mature in the lymphatic system. Wuchereria is also transmitted by some species of Anopheles and Aedes in warm countries. The nematode causes inflammation of arms, legs, scrotum or mammary glands of human beings.
Another mosquito of genus Mansonia transmits Wuchereria malayi in India and Southeast Asia, this nematode is confined only to legs. All cases of infection by Wuchereria do not result in elephantiasis.
Aedes is a widespread mosquito, it bites both by day and night. Aedes aegypti is the vector of the virus of yellow fever. Yellow fever is widespread in South America and Africa it is much more deadly than malaria.
A. aegypti and other species also carry the virus of dengue or “break bone fever”, they transmit the infection from monkeys and dengue breaks out as an epidemic in warm countries in dengue there is high temperature, rash on the skin and pain in the bones.
Disease Producing Insect # 2. Flies:
Species of Musca, the housefly transmit germs of typhoid which are picked up on the bristles of body and legs from the excreta of a patient and transferred to human food. They also transmit germs of trachoma, an eye disease of tropics, and the germs of cholera, dysentery and diarrhoea.
Glossina, the testse fly is the vector of Trypanosoma from animals to man. G palpalis and G. tachinoides transmit Trypanosoma gambiense which causes Gambian sleeping sickness. G morsitans transmits Trypanosoma rhodesiense which causes Rhodesian sleeping sicknes.
The trypanosomes are injected by the fly into the blood of man from where they reach the lymph gland and cerebrospinal fluid resulting in sleeping sickness which proves fatal. Domestic and wild animals are also susceptible to sleeping sickness, G. morsitans is also the vector of Trypanosoma brucei which causes nagana in cattle and horses, nagana is similar to sleeping sickness.
Phlebotomus, a sand-fly sucks the blood of reptiles and mammals, it spreads sand-fly fever in India and countries around the Mediterranean. Phlebotomus papatasi is the vector of sand-fly fever in which there is a pain in the eyes, stiffness in the back and neck, and a reduction of white blood corpuscles. P. papatasi and P. sergenti transmit Leishmania tropica which causes Oriental sores in India and Eastern Asiatic countries.
P. major in China and P. argentipes in India transmit Leishmania donovani which causes kala-azar fever in which the parasites enter the spleen, liver, bone marrow and endothelial cells. Kala-azar occurs in epidemic forms and proves fatal for man. P. verrucarum transmits the bacillus of Oroya fever in South American countries.
Tabanus, a gadfly and Stomoxys, a stable fly are biting and blood sucking flies, they act as vectors of Trypanosoma evansi which causes surra, a widespread tropical disease of horses and cattle, which is fatal in horses.
Tabanus and Stomoxys may also mechanically transmit Leishmania topica of Oriental sores, and bacillus of anthrax, a virulent disease of cattle. Stomoxys is the intermediate host of larvae of Hymenolepis, a tapeworm of poultry, and of larvae of Habronema, a nematode of horses.
Chrysops, the mangrove fly sucks human blood in West Africa. It is the intermediate host and vector of Filaria loa, a human nematode parasite which causes “Calabar swellings”, the nematode wanders about in the sub-cutaneous tissues, especially around the eyes.
The larvae come to the peripheral circulation by day time when Chrysops dimidiata sucks human blood, the larvae develop in the fly and are transmitted to new hosts. Chrysops discalis transmits the germs of tularaemia, a plague-like disease of rodents in America.
Hypoderma, the warble fly lays eggs on legs of cattle, in America, the larvae burrow into the skin and reach the alimentary canal. In India the larvae of Hypoderma crossii develop below the skin of the back of goats. Simulium the blackly transmits larvae of a filarial nematode Onchocera which infects man and cattle in Africa, America and Europe.
Disease Producing Insect # 3. Fleas:
Xenopsylla cheopis and X. astia are rat fleas, they suck the blood of an infected rat and transmit the bacilli of bubonic plague to man, the infection is caused by the gut getting blocked by bacilli in rat, and sucked blood is regurgitated into a wound, or infection may be caused through infected faeces of flea being rubbed into human skin by scratching.
Plague occurs in epidemic form in India. X. cheopis also transmits germs of endemic typhus from rats to man it also transmits germs of tularaemia from rats to man. Xenopsylla is an intermediate host of larvae of two tapeworms, Dipylidium caninum of dogs and cats, and Hymenolepis of rats and man.
Disease Producing Insect # 4. Bugs:
Cimex, the bed bug has been suspected of being the cause of many human diseases, but this has not been proved. In the gut of bed bugs are anti-bacterial substances which do not permit bacteria to live for long. Cimex may carry and transmit germs of plague and relapsing fever, this is only for short periods.
Three bugs Triatoma, the “assassin bug,” Panstrongylus and Rhodnius breed in human dwellings, they are the vectors of Trypanosoma cruzi which causes Chagas’ disease in South America, this disease is similar to sleeping sickness, it is a wasting disease of the brain and body, it proves fatal.
Triatoma rubrofasciata is found in India, its nymphs are common in houses hiding in crevices and under carpets, this species is concerned with transmission of kala-azar.
Disease Producing Insect # 5. Lice:
Pediculus, the louse sucks blood and takes in Rickettsia which multiply in the louse, when they are injected into human beings they cause epidemc and endemic typhus.
Pediculus also carries Rickettsia which cause trench fever in man, and the spirochaetes of relapsing fever. Trench fever and relapsing fever are spread through the excreta of louse when it is rubbed into the human skin or the louse gets crushed on the human body.
Catnip repels insects. Scientists may have finally found out how
Catnip (Nepeta cataria) may have a euphoric effect on cats, but the plant deters insects by triggering a chemical sensor for irritants, a new study shows.
Turnip Towers/Alamy Stock Photo
A whiff of catnip can make mosquitoes buzz off, and now researchers know why.
The active component of catnip (Nepeta cataria) repels insects by triggering a chemical receptor that spurs sensations such as pain or itch, researchers report March 4 in Current Biology. The sensor, dubbed TRPA1, is common in animals — from flatworms to people — and responds to environmental irritants such as cold, heat, wasabi and tear gas. When irritants come into contact with TRPA1, the reaction can make people cough or an insect flee.
Catnip’s repellent effect on insects — and its euphoric effect on felines — has been documented for millennia. Studies have shown that catnip may be as effective as the widely used synthetic repellent diethyl-m-toluamide, or DEET (SN: 9/5/01). But it was unknown how the plant repelled insects.
So researchers exposed mosquitoes and fruit flies to catnip and monitored the insects’ behavior. Fruit flies were less likely to lay eggs on the side of a petri dish that was treated with catnip or its active component, nepetalactone. Mosquitoes were also less likely to take blood from a human hand coated with catnip. Insects that had been genetically modified to lack TRPA1, however, had no aversion to the plant. That behavior — coupled with experiments in lab-grown cells that show catnip activates TRPA1 — suggests that insect TRPA1 senses catnip as an irritant.
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Puzzling out how the plant deters insects could help researchers design potent repellents that may be easier to obtain in developing countries hit hard by mosquito-borne diseases. “Oil extracted from the plant or the plant itself could be a great starting point,” says study coauthor Marco Gallio, a neuroscientist at Northwestern University in Evanston, Ill.
If a plant can make a chemical that activates TRPA1 in a variety of animals, none are going to eat it, says Paul Garrity, a neuroscientist at Brandeis University in Waltham, Mass., who was not involved in the work. Catnip probably didn’t evolve in response to predation from ancient mosquitoes or fruit flies, he says, since plants aren’t on the insects’ main menu. Instead, these insects might be collateral damage in catnip’s fight with some other plant-nibbling insect.
Catnip may deter insects like this yellow fever mosquito (Aedes aegypti) by triggering a chemical sensor that, in humans, detects pain or itch. Marcus Stensmyr
The finding “does make you wonder what the target is in cats,” says Craig Montell, a neuroscientist at the University of California, Santa Barbara also not involved with the study. The question is not only whether catnip targets TRPA1 in cats but also whether the plant might send signals through different cells — such as those for pleasure — in the feline nervous system, Montell says.
Luckily, the plant’s bug-off nature doesn’t affect people — a sign of a good repellent, Gallio says. Human TRPA1 did not respond to catnip in lab-grown cells. Plus, he says, “the great advantage is that you can grow [catnip] in your backyard.”
Though maybe don’t plant catnip in the garden, says study coauthor Marcus Stensmyr, a neuroscientist at Lund University in Sweden. A pot might be better, he says, since catnip can spread like a weed, taking over a garden.
Questions or comments on this article? E-mail us at [email protected]
A version of this article appears in the March 27, 2021 issue of Science News.