Foam-nesting Frogs Research Articles

Arboreal or terrestrial: Oviposition site of Zhangixalus frogs affects the thermal function of foam nests.

Temperature is essential for the survival and development of eggs. Some anurans have evolved and developed foam nesting traits, with thermal insulation considered to be among their functions. Foam-nesting frogs tend to exhibit reproductive plasticity. For example, they oviposit on both trees and the ground. How such plasticity affects foam nest function is of major relevance and is likely related to the adaptation of foam nesting frogs. However, this has not been well studied. In this study, we examined the interaction between foam nest site, foam nest function, and egg fate using the Japanese green tree frog, Zhangixalus arboreus, and analysed how nest site differences (arboreal or terrestrial) affect the thermal function of foam nests. We compared the thermal functions of foam nests between arboreal and terrestrial oviposition sites of Z. arboreus. We artificially replaced half of the arboreal nests with terrestrial environments and recorded temperature in and outside of the experimental terrestrial nest and original arboreal nests. We also examined egg survival and hatching rates for all the nests. The results indicated superior heat insulation in terrestrial nests, with warmer temperatures inside than outside the nests, especially at night, which led to a high egg survival rate. Therefore, terrestrial ovipositing should be valid under cold weather conditions. This may be related to the evolutionary history of oviposition site plasticity of this genus, which originally had an arboreal oviposition trait but evolved into terrestrial site use owing to global cooling. Our novel insights into the evolution and adaptivity of foam nesting and oviposition site use in Z. arboreus make an important contribution to animal ecology.

An overview of parental care in the foam-nesting frogs of the genus Leptodactylus (Anura: Leptodactylidae): current knowledge and future directions

Abstract Amphibians exhibit diverse parental care behaviours, which may be performed by the female, male or both parents. In the Neotropical family Leptodactylidae, frogs in the genus Leptodactylus exhibit different parenting behaviours. The repertoire of care behaviours includes egg/nest attendance, nest chamber sealing, tadpole feeding with trophic eggs, and tadpole attendance associated with complex behaviours, such as pumping behaviour and channel digging. Based on the available information, we found that 23.8% of Leptodactylus species are known to exhibit post-fertilization parental care. Future studies should focus on mechanisms involved in parent-offspring communication, including acoustic and chemical signals. Moreover, behaviours such as provisioning with trophic eggs are not well understood and deserves further investigation. Because of these complex parental care behaviours, tadpole schooling, and relative easy observation, frogs in the genus Leptodactylus represent excellent models for studies interested in parent-offspring communication and evolution of parental care.

Larval morphology of Amazonia foam-nesting frogs of the genus Engystomops (Anura: Leptodactylidae: Leiuperinae).

The highly differentiated anuran larvae make them an interesting and complementary source of information to understand anuran evolution. Among neotropical foam-nesting frogs, the available information on tadpole morphology for the subfamily Leiuperinae remains largely incomplete and variably reported among genera; in the monophyletic genus Engystomops it is still incipient. Herein, we summarize available information on larval morphology for five of the nine known species of Engystomops, three of them for the first time, reporting external morphology, buccopharyngeal cavity, and skeleton. The tadpoles of the genus have an overall generalized morphology and many traits are conserved across species. Nevertheless, many characters are systematically informative and some are diagnostic for some species, as the paravertebral gland in Engystomops petersi and the dorsally directed spiracle in Engystomops puyango. Other characters provide support for some subclades within the genus. Moreover, some traits, such as the direction of the vent tube, supports the close relationship between Engystomops and Physalaemus, whereas other support the existence of these two as distinct genera, such as the overall shape of the lateral ridge papillae and the presence of a processus pseudopterygoideus.

Embryonic morphology in two species of the Physalaemus signifer clade (Anura: Leptodactylidae)

We studied the embryonic morphology of Physalaemus camacan and P. signifer, two small foam-nesting frogs endemic to the Atlantic Forest. We analysed the development of transient embryonic structures and of the larval oral disc. These embryos have features typical of most congeneric species, such as the kyphotic dorsal curvature, three pairs of gills and the configuration of hatching and adhesive glands. Main differences regarding embryos of the P. cuvieri clade are the larger size and yolk provision at tailbud stage, less developed external gills and an apparently novel pattern of oral marginal papilla ontogeny. While some shifts could be correlated with variant modes of oviposition, others appear to be developmental modifications not related with ecomorphological aspects.

Early life skin microbial trajectory as a function of vertical and environmental transmission in Bornean foam-nesting frogs

BackgroundThe amphibian skin microbiome is an important mediator of host health and serves as a potential source of undiscovered scientifically significant compounds. However, the underlying modalities of how amphibian hosts obtain their initial skin-associated microbiome remains unclear. Here, we explore microbial transmission patterns in foam-nest breeding tree frogs from Southeast Asia (Genus: Polypedates) whose specialized breeding strategy allows for better delineation between vertically and environmentally derived microbes. To facilitate this, we analyzed samples associated with adult frog pairs taken after mating—including adults of each sex, their foam nests, environments, and tadpoles before and after environmental interaction—for the bacterial communities using DNA metabarcoding data (16S rRNA). Samples were collected from frogs in-situ in Brunei, Borneo, a previously unsampled region for amphibian-related microbial diversity.ResultsAdult frogs differed in skin bacterial communities among species, but tadpoles did not differ among species. Foam nests had varying bacterial community composition, most notably in the nests’ moist interior. Nest interior bacterial communities were discrete for each nest and overall displayed a narrower diversity compared to the nest exteriors. Tadpoles sampled directly from the foam nest displayed a bacterial composition less like the nest interior and more similar to that of the adults and nest exterior. After one week of pond water interaction the tadpole skin microbiome shifted towards the tadpole skin and pond water microbial communities being more tightly coupled than between tadpoles and the internal nest environment, but not to the extent that the skin microbiome mirrored the pond bacterial community.ConclusionsBoth vertical influence and environmental interaction play a role in shaping the tadpole cutaneous microbiome. Interestingly, the interior of the foam nest had a distinct bacterial community from the tadpoles suggesting a limited environmental effect on tadpole cutaneous bacterial selection at initial stages of life. The shift in the tadpole microbiome after environmental interaction indicates an interplay between underlying host and ecological mechanisms that drive community formation. This survey serves as a baseline for further research into the ecology of microbial transmission in aquatic animals.

The advertisement call of Physalaemus caete Pombal & Madureira, 1997 (Anura: Leptodactylidae: Leiuperinae), an endangered species endemic to Brazil’s northern Atlantic Forest

Foam-nesting frogs of the genus Physalaemus Fitzinger, 1826 have been long known for their diverse acoustic patterns (e.g., Barrio 1965; Bokermann 1966). Of the 49 species, the vocalizations of only three remain unknown to date (see Table 1 of Hepp Pombal 2020): P. caete Pombal Madureira, 1997, P. deimaticus Sazima Caramaschi, 1988, and P. insperatus Cruz, Cassini Caramaschi, 2008. Physalaemus caete is rare and narrowly distributed in Brazil's northern Atlantic Forest (Santos et al. 2016; Bernardo et al. 2017; Haddad et al. 2018), and an explosive breeder (EMS pers. obs.). For those reasons the species is classified in the endangered category of Brazil's red list of threatened species (ICMBio, 2018). Physalaemus caete was described in the late 1990s from the coastal region of the Brazilian state of Alagoas (Passo do Camaragibe) and reported for a second locality in Alagoas (Murici; Pombal Madureira 1997). Recently, the distribution was extended to a third locality (Paulista, state of Pernambuco; Santos et al. 2016). The distribution range of P. caete coincides with the "Pernambuco endemism center", a biogeographic subregion of coastal Atlantic Forest north of the São Francisco River (sensu Silva Casteli 2003). Here we describe the advertisement call of the Pernambuco population of P. caete and make comparisons with calls of congeners.

Systematics and historical biogeography of Neotropical foam-nesting frogs of theAdenomera heyericlade (Leptodactylidae), with the description of six new Amazonian species

AbstractA large proportion of the biodiversity of Amazonia, one of the most diverse rainforest areas in the world, is yet to be formally described. One such case is the Neotropical frog genus Adenomera. We here evaluate the species richness and historical biogeography of the Adenomera heyeri clade by integrating molecular phylogenetic and species delimitation analyses with morphological and acoustic data. Our results uncovered ten new candidate species with interfluve-associated distributions across Amazonia. In this study, six of these are formally named and described. The new species partly correspond to previously identified candidate lineages ‘sp. F’ and ‘sp. G’ and also to previously unreported lineages. Because of their rarity and unequal sampling effort of the A. heyeri clade across Amazonia, conservation assessments for the six newly described species are still premature. Regarding the biogeography of the A. heyeri clade, our data support a northern Amazonian origin with two independent dispersals into the South American Dry Diagonal. Although riverine barriers have a relevant role as environmental filters by isolating lineages in interfluves, dispersal rather than vicariance must have played a central role in the diversification of this frog clade.

Maternal provisioning by foam-nesting frogs of the genus Physalaemus (Anura, Leptodactylidae) in contrasting environments

In some environments prevailing conditions are unpredictable, thus anuran species use bet-hedging strategies and produce eggs of varied sizes. We investigated whether four species of Physalaemus (two from open, two from forest habitats) exhibit bet-hedging strategies, and if intra-clutch variation in egg size is greater for species that breed in the more unpredictable ponds of open habitats. All species studied adopted the bet-hedging strategy, with intra-clutch variation in egg size regardless of the environment; however, we found greater intra-clutch variation in the two species from open areas. The lower variation in egg-size found within forest habitats may be explained by the more stable environments that forest ponds provide for anuran eggs/embryos. Future studies in a phylogenetic context are needed to confirm the patterns detected here.

Relative testis size and mating systems in anurans: large testis in multiple-male mating in foam-nesting frogs

Abstract Comparative studies of the relative testes size in animals show that promiscuous species have relatively larger testes than monogamous species. Sperm competition favours the evolution of larger ejaculates in many animals – they give bigger testes. In the view, we presented data on relative testis mass for 17 Chinese species including 3 polyandrous species. We analyzed relative testis mass within the Chinese data set and combining those data with published data sets on Japanese and African frogs. We found that polyandrous foam nesting species have relatively large testes, suggesting that sperm competition was an important factor affecting the evolution of relative testes size. For 4 polyandrous species testes mass is positively correlated with intensity (males/mating) but not with risk (frequency of polyandrous matings) of sperm competition.

A Comparison of Oral and Topical Vitamin A Supplementation in African Foam-Nesting Frogs (Chiromantis xerampelina)

Vitamin A is essential for a variety of functions, including cellular differentiation, morphogenesis, growth, vision, immune response, and reproduction. A captive population of African foam-nesting frogs (Chiromantis xerampelina) with a known history of vitamin A deficiency had higher than expected incidence of sudden death, bacterial osteomyelitis, and stunted growth. Due to the high prevalence and untreatable nature of the diseases in the population, euthanasia of the population was recommended. Before euthanasia, the population was entered into a study to compare oral dietary supplementation of vitamin A to topical treatment with water-miscible vitamin A palmitate (AQUASOL A Parenteral, Mayne Pharma Inc., Paramus, New Jersey 07652, U.S.A.). Eighty-four frogs, weighing 2-7 g, were divided into a control and three treatment groups of 21 frogs per group, with normalized weight distribution. The control group received standard daily nutrition of crickets dusted with a supplement containing 342,000 international units (IU) vitamin A/kg. The treatment groups consisted of oral supplementation with crickets dusted with a fortified supplement containing 822,510 IU vitamin A/kg; topical vitamin A palmitate 50 IU every other day; and topical vitamin A palmitate 50 IU once a week. After 30 days, all frogs were euthanized, and 12 frogs from each group were analyzed for whole-body vitamin A levels. The control and treatment groups 1, 2, and 3 had average whole-body vitamin A levels of 1371.4 IU/kg (SE 284.4), 908.7 IU/kg (SE 186.5), 6385.9 IU/kg (SE 675.9), and 3521.8 IU/kg (SE 575.1), respectively. These results suggest that oral supplementation using a product high in vitamin A may be ineffective at raising whole-body vitamin A levels above those achieved with standard nutrition. Topical administration of vitamin A on an every other day and once a week dosing schedule achieved levels 4.5- and 2.5-fold higher than standard nutrition, respectively.

Oviduct Modifications in Foam-Nesting Frogs, with Emphasis on the GenusLeptodactylus(Amphibia, Leptodactylidae)

Various species of frogs produce foam nests that hold their eggs during development. We examined the external morphology and histology of structures associated with foam nest production in frogs of the genus Leptodactylus and a few other taxa. We found that the posterior convolutions of the oviducts in all mature female foam-nesting frogs that we examined were enlarged and compressed into globular structures. This organ-like portion of the oviduct has been called a “foam gland” and these structures almost certainly produce the secretion that is beaten by rhythmic limb movements into foam that forms the nest. However, the label “foam gland” is a misnomer because the structures are simply enlarged and tightly folded regions of the pars convoluta of the oviduct, rather than a separate structure; we suggest the name pars convoluta dilata (PCD) for this feature. Although all the foam-nesters we examined had a pars convoluta dilata, its size and shape showed considerable interspecific variation. Some of this variation likely reflects differences in the breeding behaviors among species and in the size, type, and placement of their foam nests. Other variation, particularly in size, may be associated with the physiological periodicity and reproductive state of the female, her age, and/or the number of times she has laid eggs.

Early development of the foam-nesting frogs Engystomops randi and E. coloradorum

Early development of the foam-nesting frogs Engystomops randi and E. coloradorum

WITHDRAWN: Early development of the foam-nesting frogs Engystomops randiand E. coloradorum

WITHDRAWN: Early development of the foam-nesting frogs Engystomops randiand E. coloradorum

Notes on the Biology of Pleurodema cinerea (Amphibia, Anura, Leptodactylidae) in Northwestern Argentina

Specimens of the leptodactylid frog, Pleurodema cinerea, from northwestern Argentina were examined. Feeding is generalized and foraging occurs both on the shore and in the water. Reproduction is rain initiated. Females show a positive correlation between body size and number of eggs. Hatching time, egg mortality, and larval development are discussed. Pleurodema cinerea is a little known member of a medium sized genus (10 species) of South American foam-nesting leptodactylid frogs that range from the lowlands of southern Panama to the Andes of southern Argentina and Chile (Lynch, 1971). The range of Pleurodema cinerea is restricted to the Andes of Argentina, Bolivia, and southern Peru (Parker, 1927). In Argentina it is found in the provinces of Salta, Jujuy, Catamarca, Tucuman, Cordoba, and Mendoza (Cei, 1956). It occurs from about 500 m in the foothills (Cei, 1956) to over 4,000 m in the mountains (Fernandez and Fernandez, 1929). Pleurodema cinerea has received little attention from biologists, the only ecological information relating to the species being that of Fernandez and Fernandez (1929). The present paper contributes information to the reproduction, food habits, and activity of this little known species.