Rocket Frog Research Articles

Landscape Genetics and Species Delimitation in the Andean Palm Rocket Frog (Aromobatidae, Rheobates)

The complex topography of the species-rich northern Andes creates heterogeneous environmental landscapes that are hypothesized to have promoted population fragmentation and diversification by processes such as vicariance or local adaptation. Previous phylogenetic work on the palm rocket frog (Anura: Aromobatidae: Rheobates spp.), endemic to midelevation forests of Colombia, suggested that valleys were important in promoting divergence between lineages. In this study, we first evaluated previous hypotheses of species-level diversity, then fitted an isolation-with-migration (IM) historical demographic model, and tested two landscape genetic models to explain genetic divergence within Rheobates: isolation by distance and isolation by environment. The data consisted of two mitochondrial and four nuclear genes from 24 samples covering most of the geographic range of the genus. Species delimitation by Bayesian Phylogenetics and Phylogeography recovered five highly divergent genetic lineages within Rheobates, among which few to no migrants are exchanged according to IM. We found that isolation by environment provided the only variable significantly correlated with genetic distances for both mitochondrial and nuclear genes, suggesting that local adaptation may have a role in driving the genetic divergence within this frog genus. Thus, genetic divergence in Rheobates may be driven more by variation among the local environments where these frogs live rather than by geographic distance.

Ecological and social drivers of neighbor recognition and the dear enemy effect in a poison frog

Abstract Navigating social relationships frequently rests on the ability to recognize familiar individuals using phenotypic characteristics. Across diverse taxa, animals vary in their capacities for social recognition, but the ecological and social sources of selection for recognition are often unclear. In a comparative study of two closely related species of poison frogs, we identified a species difference in social recognition of territory neighbors and investigated potential sources of selection underlying this difference. In response to acoustic playbacks, male golden rocket frogs (Anomaloglossus beebei) recognized the calls of neighbors and displayed a “dear enemy effect” by responding less aggressively to neighbors’ calls than strangers’ calls. In contrast, male Kai rocket frogs (Anomaloglossus kaiei) were equally aggressive to the calls of neighbors and strangers. This species difference in behavior is associated with key differences in reproductive ecology and characteristics of territories. Golden rocket frogs defend reproductive resources in the form of bromeliads, which is expected to create a threat asymmetry between neighbors and strangers favoring decreased aggression to neighbors. In contrast, Kai rocket frogs do not defend reproductive resources. Further, compared with Kai rocket frog territories, golden rocket frog territories occur at higher densities and are defended for longer periods of time, creating a more complex social environment with more opportunities for repeated but unnecessary aggression between neighbors, which should favor the ability to recognize and exhibit less aggression toward neighbors. These results suggest that differences in reproductive ecology can drive changes in social structure that select for social recognition.

Metabolites from Microbes Isolated from the Skin of the Panamanian Rocket Frog Colostethus panamansis (Anura: Dendrobatidae).

The Panamanian rocket frog Colostethus panamansis (family Dendrobatidae) has been affected by chytridiomycosis, a deadly disease caused by the fungus Batrachochytrium dendrobatidis (Bd). While there are still uninfected frogs, we set out to isolate microbes from anatomically distinct regions in an effort to create a cultivable resource within Panama for potential drug/agricultural/ecological applications that perhaps could also be used as part of a strategy to protect frogs from infections. To understand if there are specific anatomies that should be explored in future applications of this resource, we mapped skin-associated bacteria of C. panamansis and their metabolite production potential by mass spectrometry on a 3D model. Our results indicate that five bacterial families (Enterobacteriaceae, Comamonadaceae, Aeromonadaceae, Staphylococcaceae and Pseudomonadaceae) dominate the cultivable microbes from the skin of C. panamansis. The combination of microbial classification and molecular analysis in relation to the anti-Bd inhibitory databases reveals the resource has future potential for amphibian conservation.

Filling gaps on the endangered Cerrado Rocket Frog Allobates goianus (Bokermann, 1975) (Anura: Aromobatidae): new distributional record and comments on its daily activity

New data that seeks to fill knowledge gaps about distribution and natural history may improve our knowledge of the status of threatened species. Herein, new distributional record of the endangered species Allobates goianus is reported and information on daily activities of a population are provided using an automatic acoustic monitoring recorder. Despite the new distributional record, A. goianus has not been recorded in locations where it was previously found, we then discuss the possible causes of decline and how future efforts may help to better understand the species status.

Females prefer the calls of better fathers in a Neotropical frog with biparental care

AbstractMale secondary sexual traits potentially function as indicators of direct or indirect fitness benefits to females. Direct benefits, such as paternal care, may be especially important to females in species with biparental care. In an experimental field study of the golden rocket frog (Anomaloglossus beebei), a Neotropical species with biparental care, we tested predictions from four hypotheses proposed to explain the evolutionary relationship between male secondary sexual traits and paternal care quality (the “good parent,” “differential allocation,” “trade-off,” and “essential male care” hypotheses). We examined: 1) the influence of paternal care on offspring survival, 2) the relationships between male calls and paternal care, maternal care, and opportunities for males to acquire multiple mates, and 3) female preferences for three acoustic properties of male advertisement calls. Our results reveal that paternal care positively impacts offspring survival, that males producing longer calls also provide higher-quality paternal care in the form of greater egg attendance and territory defense, and that females prefer longer calls. Females did not discriminate among potential mates based on differences in dominant frequency or call rate. These findings, which suggest male advertisement calls are indicators of potential direct benefits to females in the form of paternal care, are consistent with the good parent hypothesis and inconsistent with the trade-off, differential allocation, and essential male care hypotheses.

“Reverse” sexual dichromatism in a Neotropical frog

AbstractSexual dichromatism is widespread among animals, but examples of “reverse” sexual dichromatism, in which females are more brightly colored than males, are extremely rare. We discovered a unique case of reverse sexual dichromatism in the golden rocket frog (Anomaloglossus beebei), a diurnal Neotropical frog. Females are bright “golden” in color, and males are drab tan with brown pigmentation that darkens when they are calling. Here, we document this color variation with calibrated digital photography and further show that there is no evidence for sex‐specific habitat matching; both sexes live in the same well‐lit habitat on green bromeliad leaves. Our results suggest that color variation in this species is an intraspecific signal and provide an important exception to the general expectation that males are more visually conspicuous in species with conventional sex roles.

Predictors and benefits of microhabitat selection for offspring deposition in golden rocket frogs

AbstractIn many tropical frogs, offspring development and survival potentially depend on microhabitat features associated with sites that parents select for oviposition and tadpole rearing. We investigated the importance of microhabitat features in the selection of oviposition sites versus tadpole rearing sites, as well as in determining offspring survival, in the golden rocket frog, Anomaloglossus beebei. Endemic to Guyana, this species exhibits biparental care and exclusively uses phytotelmata in bromeliads for oviposition and tadpole rearing. We used model‐based inference to evaluate evidence that parents prioritize different microhabitat features in selecting phytotelmata suitable for oviposition versus tadpole rearing and that microhabitat selection can adaptively promote offspring survival. For phytotelmata in 132 bromeliads, we quantified bromeliad size, phytotelm height, leaf angle (indicative of location within the bromeliad), water volume, water temperature, dissolved oxygen concentration, and the presence/absence of potential predators and nearby conspecifics. Compared to tadpole rearing sites, oviposition sites were found in phytotelmata associated with leaves at lower angles within bromeliads, smaller water volumes, lower water temperatures, higher dissolved oxygen concentrations, and more predatory crabs. Compared with unsuccessful egg clutches, successful clutches were found in phytotelmata with lower water temperatures, higher dissolved oxygen concentrations, fewer crabs, more dragonfly larvae, and more nearby conspecifics. We conclude that the nonrandom patterns of microhabitat use for oviposition sites and tadpole rearing sites in golden rocket frogs are associated with specific environmental factors that promote offspring survival through a critical stage of the animals’ complex life cycle.

The acoustic repertoire of the Atlantic Forest Rocket Frog and its consequences for taxonomy and conservation (Allobates, Aromobatidae).

The use of acoustic signals is a common characteristic of most anuran species to mediate intraspecific communication. Besides many social purposes, one of the main functions of these signals is species recognition. For this reason, this phenotypic trait is normally applied to taxonomy or to construct evolutionary relationship hypotheses. Here the acoustic repertoire of five populations of the genus Allobates from the Brazilian Atlantic Forest are presented for the first time, on a vulnerable to extinction Neotropical taxon. The description of males’ advertisement and aggressive calls and a female call emitted in a courtship context are presented. In addition, the advertisement calls of individuals from distinct geographical regions were compared. Differences in frequency range and note duration may imply in taxonomic rearrangements of these populations, once considered distinct species, and more recently, proposed as a single species, Allobates olfersioides. Calls of the male from the state of Rio de Janeiro do not overlap spectrally with calls of males from northern populations, while the shorter notes emitted by males from Alagoas also distinguishes this population from the remaining southern populations. Therefore, it is likely that at least two of the junior synonyms should be revalidated. Similarities among male advertisement and female calls are generally reported in other anuran species; these calls may have evolved from a preexisting vocalization common to both sexes. Male aggressive calls were different from both the male advertisement and female calls, since it was composed by a longer and multi-pulsed note. Aggressive and advertisement calls generally have similar dominant frequencies, but they have temporal distinctions. Such patterns were corroborated with the Atlantic Forest Rocket Frogs. These findings may support future research addressing the taxonomy of the group, behavioral evolution, and amphibian conservation.

A new account for the endangered Cerrado Rocket Frog Allobates goings (Bokermann, 1975) (Anura: Aromobatidae), with comments on taxonomy and conservation

We report a new distributional record of Allobates goianus in Niquelândia (Goias State, Central Brazil), and its rediscovery in Minacu since the creation of the Serra da Mesa dam lake in 1997. Moreover, we describe the species advertisement call from Niquelândia, reporting on a new calling emission pattern for the species, plus we provide the first comprehensive definition, diagnosis, and interspecific comparisons of A. goianus based on our two newly collected additional specimens since its original description in the mid-1970s. Allobates goianus is compared with the 22 Allobates species known to occur in Brazil due to geographic proximity. Morphological, color, and acoustic traits diagnose A. goianus from all analyzed congeners, except A. brunneus and A. olfersioides . Our study draws attention to the importance of rediscovering A. goianus at the type locality (Chapada dos Veadeiros) aiming to properly address the species limits of the three Brazilian Allobates species ( A. brunneus , A. goianus , and A. olfersioides ) that are indistinguishable with regard to phenotypic traits. The conservation status of A. goianus , endemic to the Cerrado of Central Brazil, is discussed as its natural habitats are under increased pressure due to habitat fragmentation in the Cerrado.

The complete mitochondrial genome of Anomaloglossus baeobatrachus (Amphibia: Anura: Aromobatidae)

abstractThe complete mitogenome of the rocket frog Anomaloglossus baeobatrachus was sequenced using a shotgun approach on an Illumina HiSeq 2500 platform (Illumina Inc., San Diego, CA), providing the first mitogenome for this genus. The genome was 17,572 bp long and presents the typical organization found in other neobatrachian anurans. A phylogenetic analysis including A. baeobatrachus and all other available mitogenomes of Hyloidea provided relationships in accordance with previous phylogenetic studies.

A preliminary evaluation of frog assemblages in the Pilliga forests

This paper provides a preliminary evaluation of frog assemblages in the Pilliga forests, a geographically significant region in northern New South Wales. Spotlighting and call recognition surveys were conducted at 19 sites: 14 fire dams, three woodland sites and two built environs. A total of 11 species were detected, the most frequently recorded being Litoria latopalmata (broad-palmed rocket frog). Five species were also found at sites on built environs. Of particular interest, Cyclorana alboguttata (striped burrowing frog), a rarely seen species in this region, was recorded at one dam. A desktop assessment of species records was conducted to support the field data, accounting for 10 species that were not located in the surveys.

Quantitative acoustic analysis of the vocal repertoire of the golden rocket frog (Anomaloglossus beebei)

This study describes the vocal repertoire of the Guyanan golden rocket frog, Anomaloglossus beebei, a bromeliad specialist with biparental care. Using multivariate analyses of nine call properties, as well as the occurrence of nonlinear phenomena, three signal types were distinguished-advertisement, courtship, and aggressive calls. Although all three call types were composed of a short series of rapidly repeated pulses, advertisement calls were produced at higher amplitudes and had longer pulse durations than both courtship calls and aggressive calls. Courtship calls exhibited lower dominant frequencies than both advertisement and aggressive calls, which had similar dominant frequencies. Aggressive calls had more pulses per call, had longer intervals between calls, and occasionally contained one or two introductory pulses preceding the pulsed call. Several acoustic properties predicted aspects of the signaler's body size and condition. Our study demonstrates the reliability of human observers to differentiate the multiple call types of A. beebei based on hearing calls and observing the social context in which they are produced under field conditions.

Aggregation behaviour in a neotropical dendrobatid frog (Allobates talamancae) in western Panama

Aggregation is a common behaviour in a number of animal taxa and is used for a variety of purposes. For example, aggregation may be a response to environmental resources, sexual reproductive behaviour or an antipredator response. Although commonly recognized in a variety of taxa, amongst amphibians aggregation has rarely been reported in adult poison dart frogs (family Dendrobatidae). The Talamanca striped rocket frog ( Allobates talamancae ) is a small, non-toxic leaf-litter dendrobatid frog found in the Bocas del Toro archipelago of western Panama. The purpose of our study was to describe the dispersion pattern of Allobates talamancae and elucidate a possible explanation for this pattern. Based on observations of grouping behaviour in captive frogs, we hypothesized that A. talamancae significantly aggregate in natural habitats. We conducted a series of field-based experiments that indicate that this species does significantly aggregate in the wild. Preliminary results suggest that aggregation may be an adaptive response to predation risk. We discuss this possibility, as well as critique other explanations for aggregation in this species, placing these results in the broader theoretical context of aggregation as an adaptive behaviour in animals.

Explosive Jumping: Extreme Morphological and Physiological Specializations of Australian Rocket Frogs (Litoria nasuta)

Abstract Anuran jumping is an ideal system for examining the relationships between key morphological, physiological, and kinematic parameters. We used the Australian rocket frog (Litoria nasuta) as a model species to investigate extreme specialization of the vertebrate locomotor system for jumping. We measured the ground reaction forces applied during maximal jumps using a custom-designed force platform, which allowed us to calculate instantaneous measures of acceleration, velocity, power output, and total jump distance. We quantified the mechanical properties of the plantaris longus muscle using the work loop technique. We found that L. nasuta achieved the second-longest relative jumping distance for any anuran (55.2 body lengths for one individual) and the highest published anuran values for isolated net mean muscle power output measured using work loops (93.5 W kg(-1) muscle mass), hindlimb length to snout-vent length ratio (2.02), and relative hindlimb muscle mass (33% of body mass). Litoria nasuta also had a higher ratio of tibia length to snout-vent length than 19 related species. We found that the mean power output expended during the takeoff phase of jumping in the individual that jumped the farthest was about three times greater than our estimate of available muscle power output.