We describe the distress calls of Leptodactylus chaquensis and Leptodactylus elenae. They each consist of a single, long, tonal sound with complex harmonic structure and complex frequency modulation. The distress calls of both species are different from their respective advertisement calls. Moreover, there are also clear interspecific differences. Harmonic frequencies in L. elenae are higher, there are fewer emphasized harmonics and the call is shorter and repeated at a higher rate (sometimes paired) than the call of L. chaquensis. Call duration, call rate, and position of the dominant harmonic change with the strength of the stimulus that the individuals are under; therefore, they are more variable than their respective advertisement calls

De la Riva, Ignacio

de Sá, Rafael O.

Padial, José M.

English

University of Richmond

University of RichmondUR Scholarship RepositoryBiology Faculty Publications Biology2-20-2006The Distress Calls of Leptodactylus chaquensis Cei,1950 and Leptodactylus elenae Heyer, 1978 (Anura:Leptodactylidae)José M. PadialRafael O. de SáUniversity of Richmond, rdesa@richmond.eduIgnacio De la RivaFollow this and additional works at: http://scholarship.richmond.edu/biology-faculty-publicationsPart of the Biology Commons, Population Biology Commons, Terrestrial and Aquatic EcologyCommons, and the Zoology CommonsThis Article is brought to you for free and open access by the Biology at UR Scholarship Repository. It has been accepted for inclusion in BiologyFaculty Publications by an authorized administrator of UR Scholarship Repository. For more information, please contactscholarshiprepository@richmond.edu.Recommended CitationPadial, José M., Rafael O. de Sá, and Ignacio De la Riva. "The Distress Calls of Leptodactylus chaquensis Cei, 1950 and Leptodactyluselenae Heyer, 1978 (Anura: Leptodactylidae)." Salamandra 42, no. 1 (February 20, 2006): 57-60.57Short Communicationshttp://www.salamandra-journal.com© 2006 Deutsche Gesellschaft für Herpetologie und Terrarienkunde e.V. (DGHT)The distress calls of Leptodactylus chaquensis CEI, 1950 andLeptodactylus elenae HEYER, 1978 (Anura: Leptodactylidae)JOSÉ M. PADIAL, RAFAEL DE SÁ & IGNACIO DE LA RIVAAbstract. We describe the distress calls of Leptodactylus chaquensis and Leptodactylus elenae. They eachconsist of a single, long, tonal sound with complex harmonic structure and complex frequency modulation.The distress calls of both species are different from their respective advertisement calls. Moreover, thereare also clear interspecific differences. Harmonic frequencies in L. elenae are higher, there are feweremphasized harmonics and the call is shorter and repeated at a higher rate (sometimes paired) than the callof L. chaquensis. Call duration, call rate, and position of the dominant harmonic change with the strengthof the stimulus that the individuals are under; therefore, they are more variable than their respectiveadvertisement calls.Key words: Anura: Leptodactylidae: Leptodactylus chaquensis, Leptodactylus elenae; distress call;Bolivia.Distress calls in frogs are emitted under ex-tremely dangerous circumstances as, for ex-ample, an individual being captured by apredator (HÖDL & GOLLMANN 1986). It is stillunclear which could be the actual function ofthis explosive call, although it has beensuggested as a defensive mechanism or awarning signal of risk to con-specifics (LEARY& RAZAFINDRATSITA 1998). In those specieswhere distress calls have been analysed, theystrongly differ from advertisement calls andcan be emitted by females, males, and juve-niles (DUELLMAN & TRUEB 1986, HÖDL & GOLL-MANN 1986). Nevertheless, distress calls havebeen described from only a few species; thisis particularly true in the Neotropical region(HÖDL & GOLLMANN 1986). Among Leptodac-tylus, DUELLMAN & TRUEB (1986) described thedistress call of L. pentadactylus and HÖDL &GOLLMANN (1986) described those of L. fuscus,L. ocellatus and L. pentadactylus. Duringfieldwork in Bolivia, the previously un-known distress calls of Leptodactylus cha-quensis and L. elenae were recorded. The aimof this paper is to describe these distress callsand compare them with those previouslydescribed for the genus Leptodactylus.Calls were recorded using a Sony WMD6C tape recorder and a Sennheiser Me 80directional microphone. The calls were re-corded on TDK SA60 cassettes and digitizedat a sampling frequency of 44.1 KHz and 16bit resolution with a Delta 66 digitizingboard and Peak 3.2 (OSX) software (Fonotecaof Museo Nacional Ciencias Naturales,CSIC, Madrid), and edited with Audacity1.2.2 (OSX). CoolEdit 2.0 (Syntrillium Soft-ware Corp.) was used to obtain quantitativeinformation and to generate au-diospectrograms and oscillograms on a PCcompatible computer. Frequency informa-tion was obtained through Fast FourierTransformations (FFT) (width, 1024 points).Voucher specimens were fixed in 10% forma-lin and preserved in 70% ethanol. Specimensare deposited at the Museo Nacional deCiencias Naturales, Madrid, Spain (MNCN).Digitized calls were deposited in the Fonote-ca Zoológica of the Museo Nacional deCiencias Naturales, Madrid. Air temperatureat time of recording was 19 ºC for L. chaquen-sis and 24 ºC for L. elenae, both under rela-tively dry conditions. Terminology of callcharacteristics follows MÁRQUEZ et al. (1995).Distress calls of Leptodacyltus chaquen-sis and L. elenae were first noticed whilehand-capturing specimens in the field. Torecord the calls, specimens were held by theirRheinbach, 20 February 2006 ISSN 0036-337557-60142SALAMANDRA58Short Communicationshind legs; they began to vocalize whenslightly agitated. Fifteen calls were recordedand analyzed for L. chaquensis, nine from asubadult female [MNCN 42080, snout-ventlength (SVL) 58.3 mm] and six from a juve-nile female (MNCN 42081, SVL 27.4 mm);17 calls were recorded and analyzed for L.elenae from a single adult female (MNCN42082, SVL 39.6 mm). The calls of Lepto-dactylus chaquensis were recorded in SantaCruz de la Sierra (17º 47' S, 63º 10' W),Bolivia, on 20 April 2003 at 20:30 h by J. M.PADIAL, R. DE SÁ and S. REICHLE (call references4921-22). Calls of Leptodactylus elenaewere recorded at a forest edge situation in adisturbed, open area of Amazonian lowlandforest at La Chonta (17º 39' 36" S, 63º 42' 6.6"W), Amboró National Park, DepartamentoSanta Cruz, Bolivia, on 22 April 2003 at21:00 h by J. M. PADIAL and R. DE SÁ (callreference 4923).Leptodactylus macrosternum MIRANDA-RIBERO, 1926 and L. chaquensis are siblingspecies, morphologically indistinguishable(DE LA RIVA & MALDONADO 1999). Neverthe-less, following DE LA RIVA et al. (2000), weassign the Cerrado population that weworked with from southern Bolivia to L.chaquensis, because L. macrosternum is re-stricted to Amazonian areas. Individualswere active during the night at the shore ofa pond. They emitted the distress call withthe mouth open and only when they werecaptured by hand. The call consisted on asingle, long, tonal sound with complex har-monic structure (at least seven emphasizedharmonics) and with complex frequency andintensity modulation (Fig. 1). Calls of thetwo individuals recorded differ considerablyin call rate, note duration and repetition rate(Table 1). Most energy of the call is distrib-uted among five to eight harmonics between1200-7400 Hz with a fundamental frequencybetween 600 and 800 Hz. The dominantharmonic is usually the sixth although some-times it could be the seventh or the fifth. InMNCN 42081 the call consisted of more thaneight harmonics, with most energy distrib-uted between 1500-7400 Hz; the dominantfrequency coincided with the sixth or theseventh harmonic. The call of specimenMNCN 42080 differed in having most en-ergy distributed between the fifth and eightharmonics, between 1200-5700 Hz; the do-minant harmonic is the sixth and sometimesthe fifth or seventh.La Chonta site is located less than 30 kmfrom Macuñucú, from where L. elenae hasFig. 1. Oscillogram (top) and audiospectrogram(bottom) of the distress call of a juvenile female(MNCN 42081) of Leptodactylus chaquensis,SVL= 27.4 mm.Fig. 2. Oscillogram (top) and audiospectrogram(bottom) of the distress call of an adult female(MNCN 42082) of Leptodactylus elenae,SVL=39.6.59Short Communicationsalready been reported (HEYER & HEYER 2002).The calls of L. elenae were emitted with themouth open, at a higher rate (sometimes inpairs) when the specimen was stressed. Itconsisted of a single, long, tonal sound withthree to five emphasized harmonics, and fre-quency and intensity modulation (Fig. 2,Table 1). The energy of the call is distributedin the first three harmonics, between 1600-12000 Hz; the dominant frequency is veryhigh and mostly corresponds with the thirdharmonic, but sometimes also with the fun-damental (three times) or second (one time)harmonics.The distress calls in both species are verydifferent from their respective advertisementcalls (MÁRQUEZ et al. 1995, HEYER & HEYER2002). Moreover, there are also clear inter-specific differences. Harmonic frequencies inL. elenae are higher, there are fewer empha-sized harmonics and the call is shorter andrepeated at a higher rate (sometimes paired)than the call of L. chaquensis.The distress call of Leptodactylus penta-dactylus (DUELLMAN & TRUEB 1986, HÖDL &GOLLMANN 1986) is most similar to that of L.elenae than to L. chaquensis. It also consistsof three to four emphasized harmonics, al-though the fundamental harmonic has a fre-quency between 500-2000 Hz and the domi-nant harmonic is around 3500-4000 Hz (Fig.4-18 of DUELLMAN & TRUEB 1986, Fig. 4b ofHÖDL & GOLLMANN 1986).Many Bolivian records of L. chaquensiswere previously assigned to L. ocellatus (seedistributional revision in DE LA RIVA & MAL-DONADO 1999) although the advertisementcalls of these two sibling species differ con-siderably (BARRIO 1966). The distress call ofL. ocellatus has been previously describedand illustrated (HÖDL & GOLLMANN 1986).Overall, this call is remarkably similar to thedistress call of L. chaquensis, but they differin three characteristics. The fundamental fre-quency is almost the same in both taxa butthe call of L. ocellatus is longer (615-960 ms)and it has a lower dominant frequency (0.9-3.2 kHz).The distress call of L. fuscus has also beendescribed (HÖDL & GOLLMANN 1986); it differsfrom the calls described herein in call dura-tion, although it is similar in dominant fre-quency to that of L. chaquensis. It would beinteresting to compare the distress calls of L.chaquensis with that of L. macrosternum but,unfortunately, no distress calls have beenreported for the latter.The distress calls of Leptodactylus spe-cies are complex, modulated, and with har-monic structure. They appear to be interspe-cifically variable and, thus, have taxonomicvalue; however they are not commonly usedfor taxonomic or phylogenetic analyses.This is understandable since, in distress calls,call duration, call rate, and position of thedominant harmonic change with the strengthof the stimulus that the individuals are un-der; therefore, they are more variable thanadvertisement calls (which are subject toselective pressure to warrant mate recogni-tion) and, in most cases, may not provideconsistent taxonomic information.number of call calls dominant fundamental SVL air  calls duration per frequency frequency (mm) temperatureanalysed (ms) min (Hz) (Hz) (ºC)L. chaquensis 9 545 9.49 4100 600-800 58.3 19MNCN 42080 (479-611) (2600-5200)L. chaquensis 6 360 36.99 5450 600-800 27.4 19MNCN 42081 (287-427) (4800-5800)L. elenae 17 222 23.61 7100 2700 39.6 24MNCN 42082 (191-248) (2300-9600) (1600-3400)Tab. 1. Summary of quantitative parameters of the distress calls of Leptodactylus chaquensis and L. elenae.60Short CommunicationsAcknowledgementsJMP was granted by the Mutis’ program of theMAE-AECI (Spain). We are grateful to personnelfrom Museo de Historia Natural Noel KempffMercado, specially to M. SUÁREZ, A. JUSTINIANO, R.MONTAÑO and L. GONZÁLES, by providing workingfacilities; to R. MÁRQUEZ and G. SOLÍS from Fono-teca of the Museo Nacional de Ciencias Naturales(Madrid) for his help with the analysis and storageof the calls; to S. REICHLE (TNC) for his friendshipand help during the fieldwork; to J. KÖHLER(ZFMK) for his help with the software. ToSERNAP and DGB for allowing fieldwork andcollecting in Amboró; to FERNANDO PALACIOS for hisdecisive support. This work was partially fundedby projects REN/GLO 2001-1046 (I. DE LA RIVA,Principal Investigator) and CGL2004-00401/BOS(R. ZARDOYA, Principal Investigator) of the SpanishMinistry of Science and Technology and NSFaward 0342918 to R. DE SÁ and R. HEYER.ReferencesBARRIO, A. (1966): Divergencia acústica entre elcanto nupcial de Leptodactylus ocellatus (LIN-NÉ) y L. chaquensis CEI (Anura, Leptodactyli-dae). – Physis, 26: 275-277.DE LA RIVA, I. & M. MALDONADO (1999): Firstrecord of Leptodactylus ocellatus (LINNAEUS,1758) in Bolivia (Anura: Leptodactylidae) andcomments on related forms. – Graellsia, 55:193-197.DE LA RIVA, I., J. KÖHLER, S. LÖTTERS. & S. REICHLE(2000): Ten years of research on Bolivianamphibians: updated checklist, distribution, ta-xonomic problems, literature and iconography.– Rev. Esp. Herp., 14: 19-164.DUELLMAN, W.E. & L. TRUEB (1986): The biologyof amphibians. – McGraw-Hill, New York.HEYER, W.R. & M.M. HEYER (2002): Leptodactyluselenae. – Catalogue of American Amphibiansand Reptiles, 742: 1-5.HÖDL, W. & G. GOLLMANN (1986): Distress calls inNeotropical frogs. – Amphibia-Reptilia, 7: 11-21.LEARY, C.J. & V.R. RAZAFINDRATSITA (1998): At-tempted predation on a hylid frog, Phrynohyasvenulosa by an indigo snake, Drymarchoncorais, and the response of conspecific frogs todistress calls. – Amphibia-Reptilia, 19: 442-446.MÁRQUEZ, R., I. DE LA RIVA & J. BOSCH (1995):Advertisement calls of Bolivian Leptodactyli-dae. – J. Zool., London, 237: 313-336.Manuscript received: 29 June 2005Authors‘ addresses: JOSÉ M. PADIAL, Department of Biodiversity and Evolutionary Biology, MuseoNacional de Ciencias Naturales-CSIC, C/ José Gutierrez Abascal 2, E-28006 Madrid, Spain; RAFAEL DESÁ, Department of Biology, University of Richmond, Virginia 23173, USA; IGNACIO DE LA RIVA,Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales-CSIC, C/José Gutierrez Abascal 2, E-28006 Madrid, Spain, e-mail: iriva@mncn.csic.es.

The Distress Calls of \u3cem\u3eLeptodactylus chaquensis\u3c/em\u3e Cei, 1950 and \u3cem\u3eLeptodactylus elenae\u3c/em\u3e Heyer, 1978 (Anura: Leptodactylidae)

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The Distress Calls of \u3cem\u3eLeptodactylus chaquensis\u3c/em\u3e Cei, 1950 and \u3cem\u3eLeptodactylus elenae\u3c/em\u3e Heyer, 1978 (Anura: Leptodactylidae)

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