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Frog identification - two different frogs seen in New Zealand

Frog identification - two different frogs seen in New Zealand


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Me and my friends saw these two frogs in man-made ponds in an area which is undergoing development for residential use. Anyone able to identify these beauties?

Also would be interested as to how these frogs got there, as the pond wouldn't have existed 2-3 years ago and there are none nearby.

Location these were found can be seen in the following link: https://www.pic2map.com/yibrir.html


the first frog(the green one) resemble
GREEN AND GOLDEN BELL FROG - Litoria Aurea

Description of the frog -

  • Have golden-bronze colored spots

  • Have a black line from the eye to the nostrils

  • Found in northern Island

And coming to the second frog it resembles
Southern Bell Frog - Litoria Raniformis


**Description of the frog - **

  • Have a distinctive black line running through their back

  • Found almost everywhere in new Zealand

  • They have black-brown patches on their skin (can increase in blackness based on the surrounding environment)


Coming to your question , the golden bell frog seems to stay in small temporary water ponds even puddles

On the contrary the southern bell frog lives permanently in a pond so probably it lives somewhere nearby

That'll be it


Extraordinarily ordinary: Mucus glands and mucus in the sticky toes of tree frogs

Surprisingly little is known on the nature of the secreted mucus and on the morphology of the glands that produce mucus in the sticky toes of tree frogs. In this blog, Julian Langowski, corresponding author of a new article published in Frontiers in Zoology, tells us about his 3D analysis of tree frog mucus glands and exploration of mucus chemistry.

This is a guest blog by Julian Langowski of Wageningen University and Research, the Netherlands

Mucus glands and their secretions are characteristic features of amphibian skin (Fig. 1). In previous works, the mucus glands have been mostly described as relatively uniform in form and function. Also the mucus has been said to fulfil generic functions such as enabling skin breathing and lubrication.

Sticking with wet feet

In the sticky toes of tree frogs, however, the mucus has been suggested to play another role. Here, it may act as ‘adhesive agent’, that contributes to the remarkable attachment of these animals (see our review and previous blog entry on `Kermit’s sticky little fingers’). To advance the understanding of the functional role of the mucus in tree frog attachment, we studied the virtually unknown functional gland morphology and mucus chemistry in the toes of frogs in a comparative approach. The results of this study were recently published at Frontiers in Zoology.

A previously unrecognized mucus gland cluster in amphibians?

First, we performed a micro-CT scan (similar to the procedure you might know from the hospital) of a toe of Hyla cinerea at the Paul-Scherer-Institute, Switzerland. This allowed us to create a 3D-model of all mucus glands within that toe (Fig. 2). Already at first sight, the ventral mucus glands, which open to the pad contact surface, differ clearly in their morphology from the dorsal ones. The dorsal glands show all characteristics of ‘regular’ amphibian mucus glands (i.e. small spherical glands that are abundantly present within the skin). In contrast, the bodies of the ventral mucus glands are larger, clustered, and shifted into the inner pad volume. Could this difference in morphology mean that the ventral glands play a functional role in the attachment of tree frogs?

We were excited about our discovery of the first known mucus gland cluster in amphibians, and of an apparent morphological adaptation of the mucus glands in tree frog toes. Then, however, we found in an extensive literature screening (a) that the abnormal morphology of the ventral glands has already been described by German anatomists in the 19 th century (albeit this knowledge got lost since around 1920), and (b) that gland clustering has been depicted— but not recognized — in later literaturein a minimum of 10 families of frogs. This suggests that the toe gland cluster may be a common trait in anurans (i.e. modern frogs). Importantly, we identified gland clustering also in non-arboreal frog species that do not regularly climb and stick. This observation disagrees with the hypothesis that the toe glands are specifically adapted towards attachment.

One mucus to cover them all…

Together with colleagues from The University of Akron (Departments of Polymer Science and Biology), USA, we also characterised the chemistry of the mucus on tree frog toes. By the application of molecule-specific stains to cross-sections of the toe pads (i.e. histochemistry), we showed the presence of mucosubstances such as carbohydrates and carbohydrate-protein-complexes in the toe mucus. However, none of the 10 used stains revealed a difference between the chemical signatures of the dorsal and ventral mucus of Hyla cinerea.

A more detailed analysis of the toe mucus chemistry using spectroscopic methods confirmed our histochemical findings. Neither did we discover differences in the chemistry of mucus collected from the pads and from other body locations (Fig. 4), nor did we detect distinct variations in the mucus-spectrograms collected for two arboreal and two terrestrial species of frogs.

Overall, our study shows that the chemical composition of frog mucus is similar across body locations and species with different lifestyles, suggesting that the mucus has been largely conserved in the evolution of anurans.

To stick or not to stick…

What can we learn from these findings about the fundamentals of tree frog attachment? From an evolutionary perspective, the similarity of the mucus gland morphology and mucus chemistry between species of different lifestyles disagrees with an adaptation of the mucus gland system in the toes of tree frogs towards attachment. Instead, the gland cluster may represent a more general adaptation towards a life on land: the enlarged volume of the ventral glands compared to the dorsal ones may allow frogs to compensate for the loss of mucus by physical contact of the ventral toe surface with the environment.


Introduction

Jumpamine chloride (JCl) is a natural waste product of muscle metabolism in many species of frogs (Phrogsucker et al. 1957). In addition it was reported by Phrogsucker et al. (1957) that up to 60% of this chemical is reabsorbed from the bladder before excretion. This result led to a number of studies attempting to identify the advantage of reabsorption of this product. One recent study showed that injection of JCl into the bloodstream increased muscle mass in the leopard frog Rana pipiens (Hylaflex and Smith1988). Anurheight (1990) was the first to demonstrate an actual improvement in performance capability, by showing that swimming performance in the African clawed frog Xenopus laevis was improved by adding JCl to the diet. Subsequently, in another study, tree frogs (Hyla cinerea) that had been injected with JCl were found to have measurably larger leg muscles and were able to climb higher and more quickly than those that had not (Smith 1992). The mechanism for the action of JCl on muscle growth and muscle contraction is still unknown. It may interact with enzymes involved in muscle contraction as proposed by Smith (1992) or it may directly act on the mechanical properties of the muscles themselves. This has been proposed for the action of the hormone gogetemall on muscle growth in the tree lizard Philanthropus fabricus (Herpbrain and Phutz 1992). Concerns over a recent increase in doping with JCl in frog jumping contests suggests that further study of the effect of JCl on jumping performance is necessary (Twainson 1990).

The present study was carried out in order to see if JCl had any direct effects on jumping performance in frogs of the genus Rana. We hypothesized that the increased muscle mass shown in earlier studies (Hylaflex and Smith 1988) would result in improved jumping distance. We predicted, therefore, that frogs injected with JCl should have larger muscles and jump further than frogs that had not been injected with JCl. Such a result would suggest the biological function of JCl reabsorption. We also investigated the influence of temperature in modifying the effects of JCl on jumping performance. Demonstrating temperature effects would shed light on the underlying mechanism involved in the changes in muscle induced by JCl. Based on earlier studies (Smith 1992) we hypothesized that JCl acts by affecting the enzymes associated with muscle contraction. If this is the case, and since increases in temperature also often lead to increases in enzyme activity, we predicted that jumping distance will improve exponentially with increases in temperature.

The effects of JCl on jumping performance were tested by injecting the drug into the bloodstream of the frogs and measuring average jumping distance under specific conditions. The effects of temperature on jumping distance were evaluated by carrying out the same experiments at a range of different ambient temperatures. The study was conducted on two different species of frogs, the leopard frog (Rana pipiens) and the Bullfrog (Rana catesbeiana), to see if the effects observed were species-specific or more general in nature.

Materials & Methods

The effect of JCl on jumping distance:

Ten specimens of Rana pipiens were injected with 1.0 ml. of a 10% JCl solution. Ten control frogs were given injections of 1.0 ml of a .9% NaCl solution. All frogs were maintained in 3 m square tanks at 25 0 C for 1 day in 1 inch of water. At this time each frog was placed on an open floor and induced to jump 3 times by slapping the ground behind the frog. The jumping distance was defined as the average of the 3 jumps. The same procedure was repeated using Rana catesbeiana.

The effect of temperature on jumping distance:

Each of the JCl treated frogs was placed in a 3 m square temperature controlled tank containing 1 inch of water and ranging from 0 to 90 0 C in intervals of 10 0 C. One control frog was placed in the tank with each treated frog. The frogs were left in the temperature controlled tanks for 24 hours, and then tested, as above, for jumping performance.

Results

The effects of JCl on jumping distance was studied in two species of frogs of the genus Rana at 25 0 C and subsequently on frogs that had been maintained over a broad range of temperatures.

Effect of JCl on jumping distance at 25 0 C:

As shown in Table 1 the jumping distance for the control Rana pipiens was 2.3 m and for the JCl treated Rana pipiens was 4.2 m. In Rana catesbeiana the jumping distance for the control frogs was 2.6 m and for the JCl treated frogs was 2.5 m. It is clear from Figure 1 that JCl had a striking impact on Rana pipiens, but had little or no effect on Rana catesbeiana .

The effect of temperature on jumping distance:

As seen in Table 2 the greatest jumping distance of Rana pipiens was 9.0 m at 90 0 C and the lowest jumping distance was 2.5 m at 0 0 C. As seen in Table 2 for Rana catesbeiana the greatest jumping distance was 9.1 m at 90 0 C however the lowest jumping distance was 2.0 m at 30 0 C. The relationship between temperature and jumping distance is shown for Rana pipiens in Figure 2. The same relationship for Rana pipiens is shown in Figure 3. It is clear from Figure 2 that for R. pipiens jumping distance increases linearly with temperature. For R. iwanna temperature also affects jump distance in an approximately linear fashion, but does not begin to have an effect until the temperature exceeds 30 0 C. At temperatures lower than 30 0 C jumping distance varies only slightly between 2.0 m and 2.5 m.

In addition it was noted that the treated frogs exposed to higher temperatures exhibited a measurable weight loss.

The effect of JCl on jumping distance in Rana pipiens and Rana catesbeiana at 25 0 C


Amphibian Extinction Crisis

After many years of worrying about amphibian declines and trying to pinpoint the exact cause of the problem, scientists are now faced with an even more serious problem. The declines have become so severe that scientists are now watching their study animals become extinct. We have now moved into the phase of amphibian extinctions rather than studying amphibian declines and 43% of all amphibians are threatened with extinction. When a whole group of a particular type of animal starts to disappear then we need to worry. Amphibians play an essential part in the food web of life as top insectivores and prey to many other animals, and if you remove this important link then one can only guess about the ramifications, but there is no doubt that they will be serious.

The text below contains information on the main causes of amphibian extinctions.

Global Amphibian Declines


The issue of declining frog populations was first highlighted in 1989 when a rather large group of over 1400 from 60 countries throughout the world, descended upon the delightful town of Canterbury in the UK for the First World Congress of Herpetology. It was at this meeting that a disturbing number of researchers reported apparent declines in their study populations and of growing concern were the reports of declining populations from seemingly pristine habitats. We are now nearly 20 years down the line, with over 250 publications being produced relating to global amphibian declines and as yet we are not much further ahead in identifying the cause. Throughout the World over 200 amphibian species have experienced recent population declines, with reports of at least 32 species extinctions.

So what could be the causes of declining amphibian populations? The possible causes of amphibian declines can be grouped into seven broad categories:

1. HABITAT DESTRUCTION
2. POLLUTION

Frogs vary a great deal in their tolerance to acid water. Tadpoles tolerate acidity better than embryos (fertilisation being the most sensitive developmental stage to acidity), and tolerance increases with age. Many frogs breed in temporary pools that fill up with rain. The acidity of these pools may be strongly influenced by the acidity of the rain and therefore may be considerably more acidic than that of nearby ponds and lakes. Acidification will probably constitute a major threat to our frogs.
Aluminium, cadmium, copper, zinc and iron are all toxic to amphibians. We can also infer from studies on fish that nickel, lead, and manganese will have damaging effects on frog populations. It has also been demonstrated that large amounts of lead, from car exhaust gases, are deposited into major water bodies. We can expect heavy metals to play a leading role in the downfall of our frogs.

Organic herbicides and pesticides often cause developmental abnormalities or fatalities. A report in 1997 demonstrated that the widely used and apparently safe herbicide &ldquoRoundup&rdquo was extremely toxic to tadpoles and adult frogs. This herbicide (in its new and apparently safe form) is still widely used by farmers, foresters and gardeners of New Zealand. Obviously, the insecticides DDT and Dieldrin are dangerously toxic at very low levels and at present we know very little about rates of degradation under field conditions. Certain chemicals such as DDT and PCBs mimic hormones and can cause sterility in a number of frog species and may possibly influence the fertility of humans.
Atrazine, a major herbicide used in New Zealand has been blamed for the chemical castration of frogs (and other animals, possibly humans). Prof Tyrone Hayes visited the Otago NZFROG in June in 2007. More information about this can be found on his website.


Conservation

Sub-fossil records indicate there were at least seven species of native frogs in New Zealand before the arrival of people approximately1000 years ago.  Habitat change and the introduction of non-native mammals have caused the three largest frog species to become extinct.  The remaining four New Zealand frog species all have severely reduced distributions and populations sizes.

Archey’s frog - Critically Endangered
Sub-fossil records and the two remaining disjoint populations (Coromandel Peninsula and Whareorino) suggest the mainland range of this species was once more widespread.  A sharp population decline was detected in the late 1990’s and this species is now in critical danger of extinction. 

Hamilton’s frog - Critically Endangered
One of the world’s rarest frogs with an estimated population of less than 350 individuals.  These frogs survived only in a small rocky area on mammal-free Stephens Island in the Cook Strait.  Sub-fossil indicate Hamilton’s frog was once widely distributed throughout the lower North Island and upper South Island. 

Maud Island frog - Endangered
Also restricted to a single island in the Marlborough Sounds following the arrival of humans in New Zealand.  An estimated 40 000 frogs survive in a remnant of regenerating forest on rodent-free Maud Island.

Hochstetter’s frog - Vulnerable
Ten populations of this species are known in the upper half of the North Island.  The fragmented distribution of these populations suggests the distribution of this species has become reduced following the arrival of humans. 

Conservation Threats

The four remaining species of native frogs in New Zealand face a number of threats:

•    Non-native mammals
Anecdotal evidence suggests predation and/or competition with non-native mammals may be partially responsible for historical declines of the four extant native frog species.  The distribution of frogs on the mainland became restricted following the arrival of non-native mammals and two frog species now survive only on mammal-free island refuges. 

While there is a lack of direct evidence to evaluate the exact nature of the effect of non-native mammals on native frogs, ship rats (Rattus rattus) have been documented predating upon Hochstetter’s and Archey’s frogs in North Island forests.  Non-native mammals such as pigs and goats can cause severe disturbance and degradation of habitat which may also affect native frogs.

•    Habitat change
Historical declines may also be partially attributed to the destruction of forest habitats that followed the arrival of Polynesian and European settlers.  Today, Hochstetter’s frog continues to be threatened by localised destruction of stream habitat that occurs as a result of mining, forestry and farming practices.

  •    Disease
A chytrid fungus (Batrachochytrium dendrobatidis) has been implicated in the worldwide decline of numerous amphibian species.  Frogs infected with this fungus suffer chytridiomycosis, a disease affects amphibian skin and is often fatal.   Chytrid zoospores can survive in damp conditions and may be transported between frog populations in muddy clothing and footwear.

This disease was first detected in New Zealand in 1999 in an exotic frog population in Canterbury.  It has since been identified in all populations of Archey’s frog in the upper North Island.  As a result of infection, one population of Archey’s frog on the Coromandel Peninsula has declined in numbers by over 80% resulting in a ‘Critically Endangered’ listing from the IUCN.

Conservation Action

•    Translocations
Translocation is a tool used to improve the conservation status of a species.  It is the deliberate movement of animals to an area in which they have become locally extinct.  All translocations require careful planning to ensure the factors that caused the original population to become locally extinct have been removed or controlled. Translocations also require long term planning and monitoring to assess the outcome and to determine the factors that have influenced success or failure. 

Translocations may occur for a number of reasons.  While restricted to single locations, Hamilton’s frog and Maud Island frogs were vulnerable to extinction from a stochastic event (fire, disease or invasion by a non-native mammal species).  Translocation has been used to mitigate such threats, beginning in 1985 with the intra-island translocation of 100 Maud Island frogs to suitable habitat 500 m away from their original location.  In 1997, 300 Maud Island frogs were translocated to a mammal-free island in the Marlborough Sounds.   Following the success of this translocation a further 101 frogs were moved to a second island in 2005.  Monitoring of all three populations continues today. 

Hamilton’s frog was especially vulnerable to extinction with such a small population in a confined area of Stephens Island.  The Department of Conservation initially translocated 12 frogs to specially constructed habitat also on Stephens Island.  Recently 70 Hamilton’s frog were also translocated to one of the Chetwode Islands in the Cook Strait. 

Translocation can also be used to re-introduce a species to an area in which it has become locally extinct to fulfill objectives of restoration projects.  In 2006, 60 Maud Island frogs were translocated to Karori Wildlife Sanctuary.  Karori Wildlife Sanctuary is a 252 ha restoration project 2 km from Welllington City and is surrounded by an 8.6 km fence that excludes all introduced species of mammals except mice.  This translocation is significant because it is the first translocation of a native frog back to the mainland and provides a number of unique research opportunities to gain knowledge on how mice may affect native frog populations. 

•    Disease management
The Department of Conservation and frog researchers are working hard to reduce the threat of infection by preventing the spread of chytrid fungus.  All people visiting areas with frog populations adhere to strict hygiene protocols including not taking packs, bags or gaiters into frog areas, and treating clothing, footwear and research equipment with a biocide known to kill the fungus.

•    Control of Predators
The Department of Conservation runs an active predator control programme (more information on this topic will be coming shortly).  Check out the DOC Frog web pages.

How you can help with the conservation of New Zealand’s native frogs

If you find a frog that fits the description of a native frog (click here to learn how to differentiate native frogs from introduced frogs) it is important that you do not capture or handle the frog.  Take a photograph or make notes about its appearance, its habitat and location.  Report your findings to the nearest office of the Department of Conservation as soon as possible or send in a report to NZFROG. You can also donate money to help with frog conservation projects by clicking here.
 

Remember, all native frogs are protected by the New Zealand Wildlife Management Act.  This means it is illegal to collect any native frog from the wild without a permit from the Department of Conservation (see Frogs and the Law)


Eleutherodactylus coqui (Caribbean tree frog)

E. coqui is a relatively small tree frog native to Puerto Rico, which has been introduced to Florida, Hawaii, the Galapagos Islands, New Zealand and a few other Caribbean islands. The frogs are quite adaptable to different ecological zone.

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Pictures

TitleAdult
CaptionEleutherodactylus coqui (Caribbean tree frog) adult. Habit.
Copyright©USDA Forest Service Southern Research Station/USDA Forest Service SRS/Bugwood.org - CC BY-NC 3.0 US
TitleAdult
CaptionEleutherodactylus coqui (Caribbean tree frog) adult. Habit.
Copyright©USDA Forest Service Southern Research Station/USDA Forest Service SRS/Bugwood.org - CC BY-NC 3.0 US

Identity

Preferred Scientific Name

Preferred Common Name

International Common Names

Local Common Names

Summary of Invasiveness

E. coqui is a relatively small tree frog native to Puerto Rico, which has been introduced to Florida, Hawaii, the Galapagos Islands, New Zealand and a few other Caribbean islands. The frogs are quite adaptable to different ecological zones and elevations. Their loud call is one of the main reasons they are considered a pest E. coqui's mating call is its namesake - a high-pitched, two-note "co-qui" (‘ko-kee') which attains nearly 100 decibels when measured at a distance of 0.5 metres. E. coqui has a voracious appetite and there is concern in Hawai‘i that it may put endemic insect and spider species at risk and compete with endemic birds and other native fauna which rely on insects for food.

Taxonomic Tree

  • Domain: Eukaryota
  • Kingdom: Metazoa
  • Phylum: Chordata
  • Subphylum: Vertebrata
  • Class: Amphibia
  • Order: Anura
  • Family: Leptodactylidae
  • Genus: Eleutherodactylus
  • Species: Eleutherodactylus coqui

Description

E. coqui is described as a relatively small tree frog. In Puerto Rico, mature calling males and "parental males" (males guarding a clutch) average about 34mm in length from snout to vent (snout-vent length, or SVL), while mature egg-laying females average about 41mm SVL. Like the true tree frogs (family Hylidae), E. coqui have well developed pads at the end of each toe that are used for sticking to surfaces. E. coqui individuals are extremely variable in colouration. The dorsum (upper surface) is generally grey or grey-brown and may be uniform in colour. Alternatively, they may have either a dark "M" shape between the shoulders, two broad, light dorso-lateral bars (from the snout, through to the eye, to the axilla of the rear legs) bordered with black spots and/or a light bar on top of the head between the eyes and a light underside stippled with brown ( Campbell, 2000 ). For further descriptions and pictures of different morphs see the report on E. coqui in ‘Biology and Impacts of Pacific Island Invasive Species’ (Beard et al., 2009).

Distribution

Native range: South America: Puerto Rico ( Beard et al. 2003 ).
Known introduced range: Australasia-Pacific, North America ( USGS-NAS, 2004 ), Galapagos Islands ( Snell and Rea, 1999 ).

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

North America

Oceania

South America

Habitat

E. coqui has been described as a habitat generalist. Quantitative studies on habitat preferences of E. coqui in its native range have shown that different individuals preferred different heights from the forest floor. Adults were seen to have a wider preference for a range of heights compared with juveniles. Adults have demonstrated a strong positive association with dead, fallen leaves and early successional species, such as Cecropia, Heliconia and Prestoea. E. coqui generally have positive associations with shrubs and negative associations with grasses, vines and ferns. Exceptions include Philodendron angustatum and Danea nodosa, which both have a broad leaf structure and are thus able to provide better structural support than other species in those habitat categories ( Beard et al. 2003 ). Kraus and Campbell (2002) report evidence that the ecological range of E. coqui in Hawai‘i has continued to expand. Initially the frogs were reported from relatively low elevations (0–670m). Subsequent studies show that a large population has survived and overwintered at 920m elevation. Four other populations have survived two winters at elevations of 1170m. In its native Puerto Rico, E. coqui occurs up to elevations of 1200m.

Habitat List

CategorySub-CategoryHabitatPresenceStatus
Terrestrial
Terrestrial ManagedCultivated / agricultural land Present, no further details Harmful (pest or invasive)
Terrestrial ManagedManaged forests, plantations and orchards Present, no further details Harmful (pest or invasive)
Terrestrial ManagedUrban / peri-urban areas Present, no further details Harmful (pest or invasive)
Terrestrial Natural / Semi-naturalNatural forests Present, no further details Harmful (pest or invasive)
Terrestrial Natural / Semi-naturalRiverbanks Present, no further details Harmful (pest or invasive)
Terrestrial Natural / Semi-naturalWetlands Present, no further details Harmful (pest or invasive)

Biology and Ecology

Nutrition
E. coqui is a generalist nocturnal predator and consumes an estimated 114, 000 invertebrates per hectare per night (Stewart & Woolbright, 1996 ) and even more at its highest densities in Hawai'i. It consumes invertebrates mostly on vegetation at night and in the litter during the day (Beard, 2007).

Reproduction
E. coqui reproduce year-round in their native range, but breeding activity is concentrated in the wet season. Female E. coqui lay 4-6 clutches of about 28 eggs each (range 16-41) per year. The time period between clutches is around eight weeks. E. coqui utilize internal fertilization and, like other eleutherodactylids, the fertilized eggs undergo direct development, rather than passing through a free-living larval (tadpole) stage, so standing water is not required for egg laying. E. coqui are known to utilize the nesting cavities of several bird species in Puerto Rico, including the bananaquit (Coereba flaveola portoricensis), the Puerto Rican bullfinch (Loxigilla portoricensis) and the Puerto Rican tody (Todus mexicanus). Male frogs nest in protected cavities near the ground, such as dead, curled leaves or rolled palm frond petioles. Males, which guard the eggs (to keep them from drying out), are known to leave the nest in severely dry conditions to gather moisture to rehydrate the eggs ( Campbell, 2000 ).

Lifecycle stages
E. coqui utilize internal fertilisation and, like other eleutherodactylids, the fertilized egg undergoes direct development, rather than passing through a free-living larval (tadpole) stage, so standing water is not required for egg laying. The time period between clutches is around eight weeks ( Campbell, 2000 ).
 

Notes on Natural Enemies

E. coqui forms part of the diets of birds and nocturnal mammals. They are known to be eaten by the giant crab spiders, Olios spp. and the Puerto Rican racer (a snake), Alsophis portoricensis.

E. coqui is relatively resistant to the chytrid fungus Batrachochytrium dendrobatidis
 

Means of Movement and Dispersal

Nursery trade: E. coqui was accidentally introduced in a shipment of nursery plants to Hawai'i in the late 1980s (Beard, 2006). It is thought to have entered Guam through the horticultural trade (Christy et al., 2007).
Local dispersal: Because the coqui has direct development (no tadpole phase), it was able to spread quickly, especially on the islands of Hawaii and Maui, where there are now hundreds of populations ( Beard et al., 2006 ).
 

Pathway Causes

Pathway Vectors

Impact Summary

CategoryImpact
Biodiversity (generally) Negative
Cultural/amenity Negative
Native fauna Negative
Tourism Negative
Trade/international relations Negative

Impact

In Hawai‘i the population can reach extremely high densities of up to 91,000 frogs per hectare, far exceeding those in its native range (Beard et al., 2009). In areas where E. coqui reach >50, 000 per hectare, it is estimated that they can consume around 350,000 invertebrate prey items per hectare per night. Studies have shown that E. coqui can impact upon invertebrate communities in Hawai‘i, for example, reducing both non-native and endemic native invertebrates (Choi et al., 2012 Beard et al., 2008 ). There is concern that it could compete with native insectivorous bird species. E. coqui can also affect ecosystem processes. For example it has the potential to increase foliage production rates, and nutrient cycling rates ( Beard et al., 2008 Beard et al., 2003 ). This may provide a competitive advantage to invasive plants in Hawai‘i where native species have evolved in nutrient-poor conditions (Sin et al., 2008).

In Hawai‘i there are concerns over economic impacts as well as ecological impacts (Beard et al., 2009). The cost of current E. coqui detection and control on Hawai‘i alone is $2.8 million annually. An important pathway for spread has been through the nursery trade. Quarantine restrictions and de-infestation measures are costing the nursery and floriculture industries, and customers may be more reluctant to buy due to concerns of infestation (Beard, 2006). E. coqui have spread from horticultural sites where they were first restricted, to public land, residential areas and resorts. There are concerns that property value may be affected due to the high biomass of frogs on infested sites ( Kraus and Campbell, 2002 ). The high pitched call of the frog is a disturbance and there are fears this may affect the tourism industry ( HEAR, 2004 ). Real estate prices have been negatively affected in heavily infested areas.
 

Risk and Impact Factors

  • Proved invasive outside its native range
  • Ecosystem change/ habitat alteration
  • Modification of nutrient regime
  • Negatively impacts tourism
  • Reduced amenity values
  • Reduced native biodiversity
  • Threat to/ loss of native species
  • Negatively impacts trade/international relations
  • Competition - monopolizing resources
  • Predation
  • Highly likely to be transported internationally accidentally

In its native Puerto Rico, E. coqui is considered a national symbol, and appears extensively on tourist items (Beard et al., 2009). 

Similarities to Other Species/Conditions

Two external characters serve to readily differentiate E. martinicensis from E. coqui: firstly E. martinicensis has digital discs with a smoothly rounded anterior margin, whereas E. coqui has digital discs with a straight anterior margin and secondly E. martinicensis has a distinct white chevron above the anus, which E. coqui lacks ( Kraus and Campbell 2002 ).

Prevention and Control

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Management Information

Preventative measures: Intentional transport of frogs has been banned in Hawai‘i ( Kraus and Campbell, 2002 ). In 2001, the Hawai‘i Department of Agriculture designated E. coqui as a ‘‘pest’’. This means treatment of infested materials, nursery stock etc. is mandatory (Beard et al., 2009).
 
Physical: Hand-capture is a successful method when dealing with small numbers ( Kraus and Campbell, 2002 ). Because usually only adult males call, locating females and egg masses is challenging (Beard et al., 2009). Another physical approach is habitat modification – this involves clearing of understorey vegetation in order to reduce the number of potential nesting and retreat sites (Beachy et al., 2011).

Non-chemical: A study by Hara et al. (2010) showed that a hot-water shower treatment of ornamental plants in commercial nurseries is an effective disinfestation treatment for E. coqui eggs, subadults and adults thus reducing one major potential pathway for the spread of this species. It is recommended that ornamental plants be treated to a 45° C shower for up to 5 minutes, as this regime is sufficient to achieve mortality of all stages of the frog while being within the tolerance range of many of the host plants. This method would be most effective in enclosed areas before transportation of ornamental plants. ( Hara et al. 2010 ). Orchids and bromeliads are sensitive to these heat treatments (Beard et al., 2009).

Chemical: Citric acid, caffeine and hydrated lime have been used to control E. coqui, however, according to Beard et al. (2009) citric acid is the only chemical currently used legally in Hawai‘i. Endosulfan-based pesticides can only be used in greenhouses and must be applied by a certified pesticide applicator. Spraying citric acid on infested plants to kill E. coqui eggs, juveniles and adults is a recommended option (College of Tropical Agriculture and Human Resources, undated). Aerial citric acid application of concentrations as little as 11% have been shown to reduce E. coqui density - multiple aerial sprays over a frog-infested landscape has been suggested as a control strategy (Tuttle et al., 2008). To be effective, citric acid must contact the frog directly and repeated applications may be required. Citric acid may lead to spots on leaves in some cases.

A successful eradication effort has been conducted on the Hawaiian island of O‘ahu, where there was just a single population. The eradication was a success because the population was small, and the project was well supported and funded. Citric acid was used as well as habitat modification (Beachy et al., 2011).

Control efforts may not always be supported by the public. There have been protests based on ethical concerns that have interfered with control attempts. Some find it difficult to believe that a small frog could represent a major threat also at a time when amphibian populations are declining globally, the idea of eradicating an amphibian is incongruent (Beard et al., 2009).

Bibliography

Beard KH, Pitt WC, Price EA, 2009. Biology and Impacts of Pacific Island Invasive Species. 5. Eleutherodactylus coqui, the Coqui Frog (Anura: Leptodactylidae). USDA National Wildlife Research Center - Staff Publications. Paper 864. http://digitalcommons.unl.edu/icwdm_usdanwrc/864 

References from GISD

Beard, K. H., A. K. Eschtruth, K. A. Vogt, D. J. Vogt, and F. N. Scatena. 2003. The effects of the frog Eleutherodactylus coqui on invertebrates and ecosystem processes at two scales in the Luquillo Experimental Forest, Puerto Rico. Journal of Tropical Ecology 19: 607-617.

Beard, K. H., S. McCullough, and A. K. Eschtruth. 2003. Quantitative Assessment of Habitat Preferences for the Puerto Rican Terrestrial Frog, Eleutherodactylus coqui. Journal of Herpetology 37(1): 10-17.

Beckham, Y. M., K. Nath., and R. P. Elinson. 2003. Localization of RNAs in oocytes of Eleutherodactylus coqui, a direct developing frog, differs from Xenopus laevis. Evolution and Development 5(6): 562-571.

Bomford, M., 2003. Risk Assessment for the Import and Keeping of Exotic Vertebrates in Australia. Bureau of Rural Sciences, Canberra. http://www.feral.org.au/feral_documents/PC12803.pdf

Campbell, E. W. F. Kraus, S. Joe, L. Oberhofer, R. Sugihara, D. Lease, and P. Krushelnycky., 2002. Introduced Neotropical tree frogs in the Hawaiian Islands: Control technique development and population status. In Turning the tide: the eradication of invasive species: 406 - 414. IUCN SSC Invasive Species Specialist Group. IUCN. Gland. Switzerland and Cambridge. UK.

Campbell, E.W., and F. Kraus. 2002. Neotropical frogs in Hawaii: status and management options for an unusual introduced pest. Pp. 316-318 in Timm, R.M., and R.H. Schmidt (eds.), Proceedings of the 20th Vertebrate Pest Conference. Univ. of California Press, Davis, California.

Campbell, T. S. 2000. The Puerto Rican Coqui ( Eleutherodactylus coqui Thomas 1966 ). The Institute for Biological Invasions. http://invasions.bio.utk.edu/invaders/coqui.html

Centre for Environment, Fisheries & Aquaculture Science (CEFAS)., 2008. Decision support tools-Identifying potentially invasive non-native marine and freshwater species: fish, invertebrates, amphibians. http://www.cefas.co.uk/projects/risks-and-impacts-of-non-native-species/decision-support-tools.aspx

Christy, M.T., C.S. Clark, D.E. Gee II, D.L. Vice, D.S. Vice, M.P. Warner, C.L. Tyrell, G.H. Rodda, J.A. Savidge. Recent Records of Alien Anurans on the Pacific Island of Guam. Pacific Science in press.

College of Tropical Agriculture and human Resources (CTAHR). UNDATED. Control of Coqui Frogs in Hawai'i. University of Hawai'i at Manoa. http://www.ctahr.hawaii.edu/coqui/background.asp

Eldredge, L.G. 1988. Case studies of the impacts of introduced animal species on renewable resources in the U.S.-affiliated Pacific Islands. in B.D. Smith, ed. Topic reviews on insular development in the U.S.-affiliated Islands. Univ. Guam Marine Lab Techincal Report 88, pp 26-46.

Gee II, David E., pers. comm. 2006. Wildlife Biologist, Guam Division of Aquatic & Wildlife Resources and Guam team member of the Pacific Invasives Learning Network (PILN).

Gulf States Marine Fisheries Commission (GSMFC), 2003. Eleutherodactylus coqui (Thomas). University of Southern Mississippi/College of Marine Sciences/Gulf Coast Research Laboratory. http://nis.gsmfc.org/nis_factsheet.php?toc_id=204

Hawaiian Ecosystems at Risk Project (HEAR), 2004. Alien Caribbean Frogs in Hawaii, Problematic frogs trouble people, environment. http://www.hear.org/AlienSpeciesInHawaii/species/frogs/

IUCN, Conservation International, and NatureServe. 2006. Global Amphibian Assessment. Downloaded on 4 May 2006. http://www.globalamphibians.org/

Kaiser, B., and K. Burnett. 2006. Economic Impacts of E. coqui frogs in Hawaii. Interdisciplinary Environmental Review 8:1-11. http://homepage.mac.com/ondinebak/HI_Research1_files/KaiserBurnettCoqui.pdf

Kraus, F., and E. Campbell. 2002. Human-mediated escalation of a formerly eradicable problem: The invasion of Caribbean frogs in the Hawaiian Islands. Biological Invasions 4(3): 327-332

Kraus, F., E. W. Campbell, A. Allison, AND T. Pratt. 1999. Eleutherodactylus frog introductions to Hawaii. Herpetological Review 30:21–25.

Louis A. Somma. 2008. Eleutherodactylus coqui. USGS Nonindigenous Aquatic Species Database, Gainesville, FL. http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=60

Low T, 1999. Feral Future: the Untold Story of Australia’s Exotic Invaders. Viking Press/Penguin Books Australia Ltd, Ringwood, Victoria, Australia, 380 pp

McCoid, M.J. 1993. The “new” herpetofauna of Guam, Mariana Islands. Herpetological Review 24:16-17.

Snell H and Rea S, 1999. The 1997–98 El Ni˜no in Gal´apagos: can 34 years of data estimate 120 years of pattern? Noticias de Gal´apagos 60: 11–20

Stewart, M. M., and L. L. Woolbright. 1996. Amphibians.In D. P. Reagan and R. B. Waide (eds.), The Food Web of a Tropical Rain Forest, pp. 363– 398. Univ. of Chicago Press, Chicago.

Wiles, G.J. 2000. Recent record of reptiles and amphibians accidentally transported to Guam, Mariana Islands. Micronesica 32: 285-287.

Woolbright, 1996. Disturbance influences long-term population patterns in the Puerto Rican frog, Eleutherodactylus coqui (Anura: Leptodactylidae). Biotropica 28:493–501.

References

Beachy JR Neville R Arnott C, 2011. Successful control of an incipient invasive amphibian: Eleutherodactylus coqui on O'ahu, Hawai'i. Pp. 140-147. In: Veitch CR, Clout MN, Towns DR. (eds). Island invasives: eradication and management.

Beard KH, 2006. Case Study Box: Puerto Rico and Hawaii: Wet tropical forests and the dilemma of coqui frog conservation and eradication. Pp: 135-137. In: Vogt KA, Honea J, Vogt DJ, Andreu M, Edmonds R, Berry J, Sigurdardóttir R, Patel-Weynand T. (eds.). Forests and Society: Sustainability and life cycles of forests in human landscapes.

Beard KH Pitt WC Price EA, 2009. Biology and Impacts of Pacific Island Invasive Species. Eleutherodactylus coqui, the Coqui Frog (Anura: Leptodactylidae). USDA National Wildlife Research Center - Staff Publications. Paper 864.

Distribution References

CABI, Undated. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI

Links to Websites

WebsiteURLComment
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gatewayhttps://doi.org/10.5061/dryad.m93f6Data source for updated system data added to species habitat list.
Global register of Introduced and Invasive species (GRIIS)http://griis.org/Data source for updated system data added to species habitat list.

Principal Source

Contributors

Reviewed by: Dr. Fred Kraus, Department of Natural Sciences. Bishop Mueseum Honolulu, Hawaii. USA


Conclusions

Our study found high MHC-DAB allelic diversity in L. hochstetteri as a result of positive selection and extremely high population differentiation. Nearly every population possessed a unique DAB allele pool. DAB- supertype differentiation was high among ESUs suggesting that selection pressures vary spatially and/or temporally. Northern and Central Coromandel were exceptions to this, with lower differentiation of DAB supertype frequencies, which may imply similar selective pressures as a result of shared environmental characteristics. Very low DAB diversity in Otawa, with only two alleles present, may contribute to a greater extinction risk from disease outbreaks in this ESU.


Hiding in Plain Sight

The Amazon rainforest is a beautiful place, but it is also a giant snack bar for predators. And what’s on the menu depends on how big you are. Smaller animals tend to find themselves on the menu of many larger animals. Because of this, many small animals will try to hide by blending in with their surroundings. If a larger animal can’t find them, they can avoid being eaten.

A mimic poison frog (Ranitomeya imitator) from Amazonian Peru, showing bright coloration characteristic of this species.

Other animals take a different approach. Rather than sneaking around, they will strut their stuff by sporting bright colors and/or bold patterns. It is as if they are trying to say “eat me if you dare!”

So what’s special about these animals that lets them avoid being eaten even though they stand out? As it turns out, the bright colors are meant to warn other animals to avoid eating them because they taste very bad or are poisonous. Warning coloration tells other animals that if they try to taste the poisonous animal, they will regret it.

Many different animals have this kind of coloration, from butterflies to tropical frogs. The poison frogs of South and Central America, known as dendrobatid frogs, are a great example of this. They have poisons in their skin, and their brightly colored bodies warn potential predators to back off.


National Science Foundation - Where Discoveries Begin

Leopard frog's habitat covers very small region, likely went extinct in larger territory


A new frog species has been discovered--in the midst of New York City's urban area.

March 14, 2012

This material is available primarily for archival purposes. Telephone numbers or other contact information may be out of date please see current contact information at media contacts.

In the wilds of New York City--or as wild as you can get that close to skyscrapers--scientists have found a new leopard frog species.

For years, biologists mistook it for a more widespread variety of leopard frog.

While biologists regularly discover new species in remote rainforests, finding this one in ponds and marshes--sometimes within view of the Statue of Liberty--is a big surprise, said scientists from the University of California, Los Angeles Rutgers University the University of California, Davis and the University of Alabama.

"For a new species to go unrecognized in this area is amazing," said UCLA biologist Brad Shaffer, formerly at UC Davis.

Shaffer's research is funded by the National Science Foundation's (NSF) Division of Environmental Biology.

In recently published results in the journal Molecular Phylogenetics and Evolution, Shaffer and other scientists used DNA data to compare the new frog to all other leopard frog species in the region.

"Many amphibians are secretive and very hard to find, but these frogs are pretty obvious animals," said Shaffer.

"This shows that even in the largest city in the U.S., there are still new and important species waiting to be discovered."

The researchers determined the frog is an entirely new species. The unnamed frog joins a crowd of more than a dozen distinct leopard frog species.

The newly identified wetland species likely once lived on Manhattan. It's now only known from a few nearby locations: Yankee Stadium in the Bronx is the center of its current range.

Lead paper author Cathy Newman, now of Louisiana State University, was working with Leslie Rissler, a biologist at the University of Alabama, on an unrelated study of the southern leopard frog species when she first contacted scientist Jeremy Feinberg at Rutgers University in New Jersey.

Feinberg asked if she could help him investigate some "unusual frogs" whose weird-sounding calls were different from those of other leopard frogs.

"There are northern and southern leopard frogs in that general area, so I was expecting to find one of those that for some reason had atypical behaviors or that were hybrids of both," Newman said.

"I was really surprised and excited once I started getting data back strongly suggesting it was a new species. It's fascinating in such a heavily urbanized area."

Feinberg suspected that the leopard-frog look-alike with the peculiar croak was a new creature hiding in plain sight.

Instead of the "long snore" or "rapid chuckle" he heard from other leopard frogs, this frog had a short, repetitive croak.

As far back as the late 1800s, scientists have speculated about these "odd" frogs.

"When I first heard these frogs calling, it was so different, I knew something was very off," Feinberg said.

"It's what we call a cryptic species: one species hidden within another because we can't tell them apart on sight. Thanks to molecular genetics, people are picking out species that would otherwise be ignored."

The results were clear-cut: the DNA was distinct, no matter how much the frogs looked alike.

"If I had one of these three leopard frogs in my hand, unless I knew what area it was from, I wouldn't know which one I was holding because they all look so similar," Newman said. "But our results showed that this lineage is very clearly genetically distinct."

Mitochondrial DNA represents only a fraction of the amphibian's total DNA, so Newman knew she needed to do broader nuclear DNA tests to see the whole picture and confirm the frog as a new species. She performed the work at UC Davis.

Habitat destruction, disease, invasive species, pesticides and parasites have all taken a heavy toll on frogs and other amphibians worldwide, said Rissler, currently on leave from the University of Alabama and a program director in NSF's Division of Environmental Biology.

Amphibians, she said, are great indicators of problems in our environment--problems that could potentially impact our health.

"They are a good model to examine environmental threats or degradation because part of their life history is spent in the water and part on land," Rissler said. "They're subject to all the problems that happen to these environments."

The findings show that even in densely-populated, well-studied areas, there are still new discoveries to be made, said Shaffer. And that the newly identified frogs appear to have a startlingly limited range.

"One of the real mantras of conservation biology is that you cannot protect what you don't recognize," Shaffer said. "If you don't know that two species are different, you can't know whether either needs protection."

The newly identified frogs have so far been found in scattered populations in northern New Jersey, southeastern mainland New York and on Staten Island.

Although they may extend into parts of Connecticut and northeastern Pennsylvania, evidence suggests they were once common on Long Island and other nearby regions.

They went extinct there in just the last few decades. "This raises conservation concerns that must be addressed," said ecologist Joanna Burger of Rutgers University.

"These frogs were probably once more widely distributed," Rissler said. "They are still able to hang on. They're still here, and that's amazing."

Until scientists settle on a name for the frog, they refer to it as "Rana sp. nov.," meaning "new frog species."


The new frog's range in New York and New Jersey is likely much smaller than it once was.
Credit and Larger Version

The southern leopard frog is a look-alike with the new species.
Credit and Larger Version

The pickerel frog, a species of leopard frog, is found in the same area as the new frog.
Credit and Larger Version

Media Contacts
Cheryl Dybas, NSF, (703) 292-7734, email: [email protected]
Alison Hewitt, UCLA, (310) 206-5461, email: [email protected]

The U.S. National Science Foundation propels the nation forward by advancing fundamental research in all fields of science and engineering. NSF supports research and people by providing facilities, instruments and funding to support their ingenuity and sustain the U.S. as a global leader in research and innovation. With a fiscal year 2021 budget of $8.5 billion, NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and institutions. Each year, NSF receives more than 40,000 competitive proposals and makes about 11,000 new awards. Those awards include support for cooperative research with industry, Arctic and Antarctic research and operations, and U.S. participation in international scientific efforts.


The new frog's range in New York and New Jersey is likely much smaller than it once was.
Credit and Larger Version

The southern leopard frog is a look-alike with the new species.
Credit and Larger Version

The pickerel frog, a species of leopard frog, is found in the same area as the new frog.
Credit and Larger Version


Earth News

Shiny black juvenile frogs with yellow spots dramatically change into peach coloured adults with bright blue eyes.

Scientists discovered the unique frog in a remote part of south-eastern Papua New Guinea.

The bright pattern of the young frog could act as a warning to predators, they say, but it is a mystery why the adult then loses this colour.

The scientists from Bishop Museum in Honolulu, Hawaii, US, report their findings in the journal Copeia.

Amphibian species come in a range of colours and patterns, from the brightly patterned poison dart frogs to the plainer greens of the common toad.

After metamorphosising from a tadpole, some frogs change in colour as they get older.

However, it is unknown for juveniles and adults of a species to have strikingly different colour and pattern schemes.

The research team came across the new species of frog Oreophryne ezra while on a expedition to find new species on Sudest Island, Louisiade Archipelago, off the south-eastern tip of New Guinea.

Of the new species they found, the frog particularly caught their attention.

"It's always exciting to discover a species you know to be new. However, the obviously unusual biology of this frog made its discovery especially exciting," says Dr Fred Kraus who along with Dr Allen Allison undertook the study.

"The remarkable thing about this frog is the drastic nature of its change in colour pattern as it matures from a tiny froglet into adulthood," Dr Kraus says.

As a juvenile the frog is dark black with yellow spots and black eyes but then switches to a uniform peach colour with blues eyes.

"This raises the question of what possible function the striking colours of the juveniles might serve," says Dr Kraus.

Juveniles closely resemble the general appearance of some of the poison dart frogs from the tropics.

Like these frogs, the colouration could serve as a warning to potential predators.

Although untested, the frog may also have harmful toxins in its skin like those present in poison dart frogs.

Poison dart frogs have skin that contains harmful alkaloids acting as a chemical defence against predation.

"If this is the case this would make this species another instance of the independent evolution of such a system," says Dr Kraus.

The behaviour of the frog also points to the idea that its colour advertises that it is toxic.

The researchers write how the juvenile frogs perch in conspicuous places during daylight hours and also demonstrated a lack of a well developed escape behaviour, indicating that they have another form of defence.

One aspect that cannot be explained is if the colour offers protection to the juvenile, why does the frog then change its colour scheme as it ages to one that offers no protection.

For now this poses further questions for the researchers.

"No other such instance is known in frogs," Dr Kraus says.

"If it does serve as protective warning colouration, the reason for its loss remains a mystery."


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