Produce Advertisement Calls Research Articles

Identity signaling, identity reception, and the evolution of social recognition in a Neotropical frog

Animals recognize familiar individuals to perform a variety of important social behaviors. Social recognition is often mediated by communication between signalers who produce signals that contain identity information and receivers who categorize these signals based on previous experience. We tested two hypotheses about adaptations in signalers and receivers that enable the evolution of social recognition using two species of closely related territorial poison frogs. Male golden rocket frogs (Anomaloglossus beebei) recognize the advertisement calls of conspecific territory neighbors and display a "dear enemy effect" by responding less aggressively to neighbors than strangers, whereas male Kai rocket frogs (Anomaloglossus kaiei) do not. Our results did not support the identity signaling hypothesis: both species produced advertisement calls that contain similar amounts of identity information. Our results did support the identity reception hypothesis: both species exhibited habituation of aggression to playbacks simulating the arrival of a new neighbor, but only golden rocket frogs showed renewed aggression when they subsequently heard calls from a different male. These results suggest that an ancestral mechanism of plasticity in aggression common among frogs has been modified through natural selection to be specific to calls of individual males in golden rocket frogs, enabling a social recognition system.

Oxytocin-like receptor expression in evolutionarily conserved nodes of a vocal network associated with male courtship in a teleost fish.

Neuropeptides, including oxytocin-like peptides, are a conserved group of hormones that regulate a wide range of social behaviors, including vocal communication. In the current study, we evaluate whether putative brain sites for the actions of isotocin (IT), the oxytocin (OT) homolog of teleost fishes are associated with vocal courtship and circuitry in the plainfin midshipman fish (Porichthys notatus). During the breeding season, nesting males produce advertisement calls known as "hums" to acoustically court females at night and attract them to nests. We first identify IT receptor (ITR) mRNA in evolutionarily conserved regions of the forebrain preoptic area (POA), anterior hypothalamus (AH), and midbrain periaqueductal gray (PAG), and in two topographically separate populations within the hindbrain vocal pattern generator- duration-coding vocal prepacemaker (VPP) and amplitude-coding vocal motor nuclei (VMN) that also innervate vocal muscles. We also verify that ITR expression overlaps known distribution sites of OT-like immunoreactive fibers. Next, using phosphorylated ribosomal subunit 6 (pS6) as a marker for activated neurons, we demonstrate that ITR-containing neurons in the anterior parvocellular POA, AH, PAG, VPP, and VMN are activated in humming males. Posterior parvocellular and magno/gigantocellular divisions of the POA remain constitutively active in nonhumming males that are also in a reproductive state. Together with prior studies of midshipman fish and other vertebrates, our findings suggest that IT-signaling influences male courtship behavior, in part, by acting on brain regions that broadly influence behavioral state (POA) as well as the initiation (POA and PAG) and temporal structure (VPP and VMN) of advertisement hums.

Multisensory modalities increase working memory for mating signals in a treefrog.

Animal choruses, such as those found in insects and frogs, are often intermittent. Thus, females sampling males in the chorus might have to remember the location of the potential mates' calls during periods of silence. Although a number of studies have shown that frogs use and prefer multimodal mating signals, usually acoustic plus visual, it is not clear why they do so. Here we tested the hypothesis that preference for multimodal signals over unimodal signals might be due to multimodal signals instantiating longer memories than unimodal signals, particularly during the inter-chorus intervals. We tested this hypothesis in serrate-legged small treefrogs Kurixalus odontotarsus whose males produce advertisement calls accompanied by conspicuous vocal sac inflation. Females were tested with acoustic and acoustic+visual (video of inflating-deflating vocal sac) mating calls. We found that females prefer multimodal calls over unimodal, audio-only calls. Furthermore, multimodal calls are still preferred after a silent period of up to 30s, a time that spans the average silent period of the chorus. This was not true of unimodal calls. Our results demonstrate that a multimodal signal can engage longer working memory than a unimodal signal, and thus female memory might favour the evolution of multimodal signals in males through sexual selection. Selection might also favour female preference for multimodal signals if longer memory facilitates mate searching and assessment. Our study does not allow us to elucidate the sequence of evolution of this trait and preference.

Reciprocal Matched Filtering in the Inner Ear of the African Clawed Frog (Xenopus laevis).

Anurans (frogs and toads) are the most vocal amphibians. In most species, only males produce advertisement calls for defending territories and attracting mates. Female vocalizations are the exceptions among frogs, however in the African clawed frog (Xenopus laevis) both males and females produce distinct vocalizations. The matched filter hypothesis predicts a correspondence between peripheral auditory tuning of receivers and properties of species-specific acoustic signals, but few studies have assessed this relationship between the sexes. Measuring hearing sensitivity with a binaural recording of distortion product otoacoustic emissions, we have found that the ears of the males of this species are tuned to the dominant frequency of the female's calls, whereas the ears of the females are tuned close to the dominant frequency of the male's calls. Our findings provide support for the matched filter hypothesis extended to include male-female calling. This unique example of reciprocal matched filtering ensures that males and females communicate effectively in high levels of background noise, each sex being most sensitive to the frequencies of the other sex's calls.

Whispers on the wind: male cane toads modify mate searching and amplexus tactics based on calls from other males

In many species of anurans, males produce advertisement calls that function to attract reproductively active females. Rival males may use the public information in these calls to optimize their own tactics for acquiring mates. To see whether male cane toads, Rhinella marina, modify their mate-searching and amplexus behaviours in response to conspecific calls, we monitored toads in outdoor enclosures while playing recordings of advertisement calls, a biologically irrelevant stimulus with similar acoustic properties or silence. Male toads were seven times more likely to engage in amplexus and moved twice as much during a toad chorus than during the control sound or silence. Nonacoustic cues also influenced propensity to initiate amplexus, with males five to 16 times more likely to amplect a moving target than a stationary one (regardless of the sex of the animal being amplexed). Our study shows that male toads dramatically alter their behaviour in response to acoustic and visual information from conspecifics, suggesting that this public information holds substantial value to them as they seek to fine-tune their own reproductive tactics.

Dueling frogs: do male green tree frogs (Hyla cinerea) eavesdrop on and assess nearby calling competitors?

Individuals produce advertisement signals with intended purposes and targets. However, these signals can be received by “eavesdroppers,” who may extract information from them and alter their behavior according to the extracted information. In anuran systems, males congregate at breeding sites to produce advertisement calls to attract receptive females and fend off rival males. Both sexes directly assess these calls in dyadic encounters and make decisions based on the call’s characteristics, e.g., frequency. What is unknown is whether bystander males eavesdrop on these same calls to inform their future competitive decisions. Here, we examined whether male green tree frogs (Hyla cinerea) eavesdrop on competing males, assess their competitor’s call frequency, and respond accordingly. We exposed males to playbacks of two competing males that varied in call frequency—high, average, low—and quantified latency to call, time spent calling, and number of calling bouts. We found that males had reduced latency to call and called more when eavesdropping low-frequency competition, but not average or high-frequency competition. Focal male size also influenced how they responded, with larger males being more responsive than smaller males. Our results indicate that male green tree frogs are capable of eavesdropping on nearby male calls and produce behavioral responses accordingly. Further, it appears males are able to alternate between assessment strategies dependent upon the frequency of the eavesdropped competition. These findings indicate that males not only directly assess an opponent’s call in dyadic encounters, but also indirectly through eavesdropping. SIGNIFICANCE STATEMENT: Animals produce signals with intended purposes and targets, but which can be received by nearby eavesdroppers. Eavesdropped signals can elicit complex phenotypic changes in the eavesdropper, and lead to significant fitness consequences for the signal producer and eavesdropper. Thus, examining whether and to what extent individuals eavesdrop is an important step in understanding the evolution of signal production and response. Here, we examined whether male green tree frogs, H. cinerea, eavesdrop on nearby competing males and base their own calling behaviors on eavesdropped male’s calling characteristics. Calling behavior was mediated by focal male body size and eavesdropped male’s call frequency. Larger males reduced response latency and called more to nearby low-frequency males, while smaller males reduced response latency to nearby calls of average frequency. These results indicate that males will extract information from their competitive environment through eavesdropping and produce behavioral responses according to the eavesdropped information.

Auditory neural networks involved in attention modulation prefer biologically significant sounds and exhibit sexual dimorphism in anurans.

Allocating attention to biologically relevant stimuli in a complex environment is critically important for survival and reproductive success. In humans, attention modulation is regulated by the frontal cortex, and is often reflected by changes in specific components of the event-related potential (ERP). Although brain networks for attention modulation have been widely studied in primates and avian species, little is known about attention modulation in amphibians. The present study aimed to investigate the attention modulation networks in an anuran species, the Emei music frog (Babina daunchina). Male music frogs produce advertisement calls from within underground nest burrows that modify the acoustic features of the calls, and both males and females prefer calls produced from inside burrows. We broadcast call stimuli to male and female music frogs while simultaneously recording electroencephalographic (EEG) signals from the telencephalon and mesencephalon. Granger causal connectivity analysis was used to elucidate functional brain networks within the time window of ERP components. The results show that calls produced from inside nests which are highly sexually attractive result in the strongest brain connections; both ascending and descending connections involving the left telencephalon were stronger in males while those in females were stronger with the right telencephalon. Our findings indicate that the frog brain allocates neural attention resources to highly attractive sounds within the window of early components of ERP, and that such processing is sexually dimorphic, presumably reflecting the different reproductive strategies of males and females.

A new species of Bryophryne (Anura: Strabomantidae) from the Cordillera de Vilcabamba, southeastern Peruvian Andes

We describe a new species of Bryophryne from the Cordillera de Vilcabamba in Department Cusco, in the southeastern Peruvian Andes. The new species differs from all other congeneric taxa, except B. flammiventris and B. gymnotis, by possessing a weakly defined tympanic membrane and tympanic annulus, by the presence of vocal sac and vocal slits in males, and by producing advertisement calls. The new species is distinguished from B. flammiventris and B. gymnotis by skin texture, presence of small, oblique dentigerous processes on the vomer, ventral coloration ranging from bluish-gray to whitish-gray with irregular or reticulate dark brown spots, and call composed of two or three notes. The new species is further characterized by having dorsal skin shagreen with tubercles, discontinuous dorsolateral folds, skin smooth on ventral surfaces of the body, and lateral fringes on fingers and toes. This species was found at the transition from montane forest to high Andean puna, where it occurs in moist microhabitats under moss and rocks at elevations from 3519 to 3707 m a.s.l.

Evidence of auditory insensitivity to vocalization frequencies in two frogs

The emergence and maintenance of animal communication systems requires the co-evolution of signal and receiver. Frogs and toads rely heavily on acoustic communication for coordinating reproduction and typically have ears tuned to the dominant frequency of their vocalizations, allowing discrimination from background noise and heterospecific calls. However, we present here evidence that two anurans, Brachycephalus ephippium and B. pitanga, are insensitive to the sound of their own calls. Both species produce advertisement calls outside their hearing sensitivity range and their inner ears are partly undeveloped, which accounts for their lack of high-frequency sensitivity. If unheard by the intended receivers, calls are not beneficial to the emitter and should be selected against because of the costs associated with signal production. We suggest that protection against predators conferred by their high toxicity might help to explain why calling has not yet disappeared, and that visual communication may have replaced auditory in these colourful, diurnal frogs.

Calling behavior of males and females of a Bornean frog with male parental care and possible sex-role reversal

In many species that use acoustic signals for mate attraction, males are usually the most vocal sex. In frogs, females typically remain silent, while males produce advertisement calls to attract mates. In some species, females vocalize, but usually as a response to an initial male advertisement call. The smooth guardian frog (Limnonectes palavanensis), found on Borneo, has exclusive paternal care while the females mate and desert after laying the clutch. Males provide care to the eggs until hatching and then they transport the tadpoles to small bodies of water. The vocal repertoire of this species has never been described. Males have a distinctive advertisement call to attract females, but produce the call very infrequently. We found that females of L. palavanensis not only respond to male advertisement calls but also vocalize spontaneously, forming lek-like aggregations around a single male. Males may or may not respond to a particular female with a short courtship call, which is elicited only by the female call and not the male advertisement call. The calling rate of females is consistently higher throughout the night compared with the calling rate of males. These observations suggest that this species exhibits a reversal in calling behavior and possibly a sex-role-reversed mating system. Exceptional cases of species with a sex-role reversed mating system have been observed in fishes and birds, but not in frogs. For sex-role reversal to occur, there must be intense parental care by the males and a surplus of females. Additionally, females should exhibit characteristics that are usually observed in males in species with conventional sex roles. We found that in L. palavanensis, females are highly vocal, exhibiting higher calling rates compared with the calling rates of the males. This behavior, where females out-signal males has not been observed in anurans. This female calling behavior coupled with observations of several females approaching a male provides evidence of a female-biased operational sex ratio, a characteristic of a sex-role-reversed mating system. Thus, this study provides quantitative evidence that L. palavanensis exhibits various aspects consistent with a sex-role reversed mating system.

Temporal and spatial differentiation in microhabitat use: Implications for reproductive isolation and ecological niche specification.

Niche differentiation enables ecologically similar species to coexist by lessening competition over food and/or shelters and may be critical for reproductive isolation between closely related species in close proximity. Because no extra traits need to evolve, spatial and temporal differentiation may readily take place to complement other isolating mechanisms. Two closely related treefrog species occur together in Korea: the endangered Hyla suweonensis and the widespread Hyla japonica. Advertisement calls are differentiated, but it is unclear whether call difference is sufficient for reproductive isolation. We tracked individuals of both species to study fine-scale differentiation in microhabitat use in the diel cycle of the breeding season using a harmonic direction finder. tracking male movement patterns of both species revealed spatial and temporal differentiation in microhabitat use for calling and resting during the breeding season. Males of both H. suweonensis and H. japonica occurred in all 5 microhabitats identified in this study: rice paddy, ground, buried, grass and bush. Both treefrog species showed general similarities in calling from rice paddies and resting in grass and bush. However, H. suweonensis moved into rice paddies and produced advertisement calls 3 h earlier than H. japonica. These differences likely minimize contact between the species and provide an additional isolating mechanism. In addition, the activity of H. suweonensis may be contributing to the decline of this species, as resting in grass would increase dangers from predatory birds and habitat disturbance.

Development and sexual dimorphism of the sonic system in deep sea neobythitine fishes: The upper continental slope

The anatomy of sound production in continental-slope fishes has been ignored since the work of NB Marshall in the 1960s. Due to food scarcity at great depths, we hypothesize that sonic muscles will be reduced in deep-water neobythitine cusk-eels (family Ophidiidae). Here we describe and quantify dimensions of the swimbladder and sonic muscles of three species from the upper slope. They have four pairs of well-developed sonic muscles (two medial and two lateral) with origins on the skull and insertions on the medial swimbladder (medial pair) or on modified epineural ribs that attach to the lateral swimbladder (lateral pair). Despite minor differences, relatively similar swimbladder dimensions, muscle length and external morphology suggest a conservative body plan. However, there are major differences in sonic muscle mass: medial muscles are heavier in males and made of relatively small fibers (ca 10µm in diameter). Lateral muscles are generally larger in females and consist of larger fibers, as in epaxial trunk muscle. Muscle weight varies between species, and we suggest males produce advertisement calls that vary in amplitude and duration in different species. Due to differences in fiber size, we hypothesize that lateral muscles with larger fibers remain contracted during sound production, and medial muscles with smaller fibers will oscillate to drive swimbladder sound production.

Calling rate, corticosterone plasma levels and immunocompetence of Hypsiboas albopunctatus

During the breeding season, male anuran amphibians produce advertisement calls. Androgens play a permissive role in the activation of calling activity, which is often positively correlated to androgen plasma levels and testes mass. Additionally, calling effort is also correlated to corticosterone plasma levels (hereinafter referred to as CORT), which is associated with the mobilization of energy substrates to sustain the high energy flux associated with this activity. However, high CORT also has many immunosuppressive effects and might interfere with reproduction. Consequently, CORT might mediate a compromise between reproductive effort and immunocompetence in anurans. In the present study, we investigated the relationship between calling rate, immunocompetence, and CORT in Hypsiboas albopunctatus, a midsize anuran occurring in South America. To understand these relationships, we conducted focal observations of calling behavior, followed by blood collection for CORT measurements and evaluation of some immune parameters. Our results showed that individuals with larger testes had higher calling rates, and those with higher calling rates showed lower cell-mediated immune response (swelling response to phytohaemagglutinin), although these relationships were not mediated by CORT. Furthermore, males calling early in the evening showed high CORT, and individuals with lower body condition index had higher CORT. We conclude that calling activity shows a cost in terms of cellular immune response in H. albopunctatus, but this compromise does not appear to be mediated by glucocorticoid plasma levels.

A new species of Pristimantis (Amphibia, Anura, Craugastoridae) from the foothills of the Andes in Manu National Park, southeastern Peru.

We describe a new species of Pristimantis from the humid sub-montane forest of the Región Cusco in Peru. Pristimantis pluvialis sp. n. was collected in the Kosñipata and Entoro valleys at elevations from 740 to 1110 m a.s.l., near the borders of Manu National Park and within the Huachiperi Haramba Queros Conservation Concession. The new species can be distinguished from other members of the genus Pristimantis by its rostral tubercle, smooth dorsal skin, and by its advertisement call. Pristimantis lacrimosus and Pristimantis waoranii superficially most resemble the new species, but Pristimantis pluvialis sp. n. differs from both species by having a rostral tubercle (absent in Pristimantis waoranii and variable in Pristimantis lacrimosus) and larger size, from Pristimantis lacrimosus by its call emitted at a lower frequency, and from Pristimantis waoranii for its dorsal coloration with dark markings. Two other species have partially overlapping distributions and resemble the new species, Pristimantis mendax and Pristimantis olivaceus, but they produce advertisement calls with much higher dominant frequencies than the advertisement call of the new species. Furthermore, Pristimantis mendax differs from the new species by lacking a rostral tubercle and by having a sigmoid inner tarsal fold, whereas Pristimantis olivaceus differs by being smaller and by having dorsal skin shagreen with scattered tubercles. The new species has snout-vent length of 21.8–26.9 mm in males (n = 12) and 28.8 mm in a single female.

Spatiotemporal variability and sound characterization in silver croaker Plagioscion squamosissimus (Sciaenidae) in the Central Amazon.

BackgroundThe fish family Sciaenidae has numerous species that produce sounds with superfast muscles that vibrate the swimbladder. These muscles form post embryonically and undergo seasonal hypertrophy-atrophy cycles. The family has been the focus of numerous passive acoustic studies to localize spatial and temporal occurrence of spawning aggregations. Fishes produce disturbance calls when hand-held, and males form aggregations in late afternoon and produce advertisement calls to attract females for mating. Previous studies on five continents have been confined to temperate species. Here we examine the calls of the silver croaker Plagioscion squamosissimus, a freshwater equatorial species, which experiences constant photoperiod, minimal temperature variation but seasonal changes in water depth and color, pH and conductivity.Methods and Principal FindingsDissections indicate that sonic muscles are present exclusively in males and that muscles are thicker and redder during the mating season. Disturbance calls were recorded in hand-held fish during the low-water mating season and high-water period outside of the mating season. Advertisement calls were recorded from wild fish that formed aggregations in both periods but only during the mating season from fish in large cages. Disturbance calls consist of a series of short individual pulses in mature males. Advertisement calls start with single and paired pulses followed by greater amplitude multi-pulse bursts with higher peak frequencies than in disturbance calls. Advertisement-like calls also occur in aggregations during the off season, but bursts are shorter with fewer pulses.Conclusions and SignificanceSilver croaker produce complex advertisement calls that vary in amplitude, number of cycles per burst and burst duration of their calls. Unlike temperate sciaenids, which only call during the spawning season, silver croaker produce advertisement calls in both seasons. Sonic muscles are thinner, and bursts are shorter than at the spawning peak, but males still produce complex calls outside of the mating season.

Male-Biased Sexual Size Dimorphism, Resource Defense Polygyny, and Multiple Paternity in the Emei Moustache Toad (Leptobrachium boringii)

We tested the hypotheses that the Emei moustache toad (Leptobrachium boringii) exhibits resource defense polygyny and that combat led to the evolution of male-biased sexual size dimorphism. Between February and March of 2011 and 2012, 26 female and 55 male L. boringii from Mount Emei UNESCO World Heritage Site, Sichuan, China, were observed throughout the breeding season. Prior to the breeding season, males grow 10–16 keratinized maxillary nuptial spines, which fall off once the season has ended. Throughout this time, males construct and defend aquatic nests where they produce advertisement calls to attract females. In a natural setting, we documented 14 cases involving a total of 22 males where males used their moustaches for aggressive interaction, and nest takeover was observed on seven occasions. Males were also observed to possess injuries resulting from combat. Genetic analysis using microsatellite DNA markers revealed several cases of multiple paternity, both within nest and within clutch. This observation indicated that some alternative male reproductive strategy, such as satellite behaviour, is occurring, which may have led to the multiple paternity. Larger males were observed to mate more frequently, and in multiple nests, suggesting that females are selecting for larger males, or that larger males are more capable of defending high quality territories.

Coding of anuran vocalization by a single type of premotor neuron

Motor programs are composed of movements that are coordinated with precise timing. For example, human speech involves very rapid movements that control articulation on a msec time scale. How are temporally precise motor programs generated by the nervous system? We addressed this question by conducting an electrophysiological experiment using vocalizations of African clawed frog (Xenopus laevis) as a model. The central vocal pathway of Xenopus is a tractable system that allows experimental manipulation while the brain is engaged in “fictive vocalizations” in vitro. Male Xenopus produce advertisement calls consisting of alternating fast and slow trills, each of which contains trains of clicks repeated at ~60 and 30Hz, respectively. Using patch‐clamp whole‐cell recordings, we discovered a type of premotor neuron that codes for both click rates and trill durations. The neurons, termed fast trill neurons (FTNs), show NMDA receptor‐dependent plateau potentials that coincide with the fast trill. Furthermore, the neurons fire a series of action potentials during the fast trill with each spike preceding motor output by ~4 msec. Interestingly, the FTNs exhibit both subthreshold oscillations and spike timing preference exactly at 60 Hz, the frequency of the fast trills. We conclude that complicated temporal patterns of Xenopus vocalizations can be encoded by the intrinsic properties of a single type of premotor neuron.

Male Position Relative to Foam Nests Influences Female Mate Choice in the Túngara Frog, Physalaemus pustulosus

Vocalizations are critical advertisement signals used during anuran courtship. In most species, acoustic signals have primacy, but visual cues also have been shown to play an important role in anuran mate attraction. Male Túngara Frogs, Physalaemus pustulosus, produce advertisement calls, and males that are successful in attracting a mate build conspicuous white foam nests in which fertilized eggs are deposited. Foam nests persist for several days and on subsequent nights, male frogs are often observed calling adjacent to these foam nests. We tested the hypothesis that females approach the vocalization of a male adjacent to a foam nest preferentially. We conducted choice tests allowing females to choose between two speakers broadcasting a male vocalization—one speaker adjacent to a foam nest and the other speaker lacking a foam nest. Females expressed a significant preference for a speaker with a foam nest when the nest was visible. These results indicate that males may increase their probability of attracting a mate when calling adjacent to a foam nest relative to males located farther from a foam nest.

New Species of Marsupial Frog (Hemiphractidae: Gastrotheca) from an Isolated Montane Forest in Southern Peru

We describe a new species of marsupial frog (genus Gastrotheca) from an isolated patch of cloud forest in the upper reaches of the Pachachaca River, a tributary of the Apuro ´mac River in southern Peru (Apuro ´mac Region). The new species is small with males less than 30 mm and a single female 35.3 mm in snout-vent length. A juvenile was collected from inside an epiphytic bromeliad at ,3 m, suggesting that this species is arboreal or uses bromeliad tanks as microhabitats. We describe the advertisement call, which has a dominant frequency above 2.2 kHz. Based on morphology and advertisement call, the new species is most similar to Gastrotheca piperata described from the Yungas of Bolivia. The new species differs from G. piperata by having smaller size, no dermal fold on the tarsus, a bluntly rounded to vertical snout in profile, gray coloration on dorsal surfaces of Fingers I and II and by producing advertisement calls that have a higher dominant frequency and a smaller number of pulses. RESUMEN.—Describimos una nueva especie de rana marsupial (genero Gastrotheca) de un parche aislado de bosque nublado en las nacientes del ro ´o Pachachaca, un afluente del ro ´o Apuro ´mac en el sur de Peru ´ (Region Apuro ´mac). La nueva especie es pequena, con machos que miden menos de 30 mm y una hembra 35.3 mm en longitud hocico-cloaca. Un juvenil fue capturado dentro de una bromelia epo ´fita a una altura de ,3 m, lo cual sugiere que esta rana es arborea o usa las bromelias como microhabitats. Describimos el canto nupcial, cuya frecuencia dominante es de mas de 2.2 kHz. En base a morfologo ´a y canto nupcial, la nueva especie se asemeja masa Gastrotheca piperata descrita de las Yungas de Bolivia. La nueva especie se diferencia de G. piperata por su menor tamano, ausencia de pliegue tarsal, hocico redondeado o vertical en vista lateral, coloracion gris en la superfice dorsal de los dedos I y II y por producir un canto nupcial con frecuencia dominante mas alta y menor numero de pulsos. Biological inventories and phylogenetic and taxonomic research in the cloud forests of southeastern Peru over the past decade have led to the description of many new species of amphibians (Lehr and Catenazzi, 2008, 2009a,b). These recent discoveries point to the exceptional diversity of montane and high-elevation taxa in the eastern slopes of the Andes. Beta diversity of montane taxa is likely to be much higher than currently known, and as new inventories are conducted, we predict that many additional species will be discovered. These discoveries will help us better understand patterns of species abundance and distribution in relation to the heterogeneous environment of the eastern cordilleras and inter-Andean valleys of southern Peru. The herpetofauna of the Apurimac region is poorly known. The west and central portions of this region are dominated by species that have a wide geographic distribution in the puna and other high-elevation habitats of the Peruvian Altiplano, such as Gastrotheca marsupiata, Pleurodema marmoratum, and Tachymenis peruviana. However, the eastern portion of the Apurimac Region has more species, several of which are endemic. The inter-Andean dry valleys of the Apurimac canyon and of its tributaries, for example, are inhabited by two endemic squamates, the lizard Stenocercus apurimacus and the snake Drymoluber apurimancesis (Lehr et al., 2004). These valleys often present heterogeneous environments, from dry, scrublike vegetation in places where the cordilleras function as rain shadows, to cloud forests where local topography intercepts moisture and favors the formation of fog. Many of these habitats are difficult to access and are poorly known biologically. Based on museum collections, G. marsupiata is the only marsupial frog that has been reported previously from Apurimac. William E. Duellman collected a series of this species in four locations between Abancay and Huancavelica (voucher specimens at the Museum of Natural History,

Phonotaxis to male’s calls embedded within a chorus by female gray treefrogs, Hyla versicolor

During the reproductive season, male Hyla versicolor produce advertisement calls to attract females. Females exhibit phonotaxis and approach the individual callers, resulting in amplexus. For frogs that call from dense choruses, the extent to which and the range from which a male's advertisement call within a chorus can be heard by a receptive female leading to phonotaxis is unclear. We investigated females' responses to natural choruses in the field and found that they were attracted and showed directed orientation to breeding choruses at distances up to 100 m. To assess the role of acoustic cues in the directed orientation, we conducted acoustic playback experiments in the laboratory using conspecific call and noise as stimuli, as well as chorus sounds (that contained calls from a focal male) recorded at various distances, all played at naturalistic intensities. Using two response metrics (females' normalized response times and their phonotaxis trajectories) we found that, unlike the field experiments, females oriented and were attracted to chorus sounds from 1 to 32 m only, but not from >32 m, or to band-limited noise. Possible reasons for the observed difference in phonotaxis behavior in the two experimental conditions were discussed.