02213nas a2200241 4500008004100000245010200041210006900143300001200212490000700224520146900231653001101700653000901711653001701720653002101737653002501758653002601783653002501809653002601834653002101860100002701881700002201908856004101930 1997 eng d00aA New Examination of Echolocation Calls of Some Neotropical Bats (Emballonuridae and Mormoopidae)0 aNew Examination of Echolocation Calls of Some Neotropical Bats E a954-9630 v873 a

In northwestern Belize, two emballonurids Rhynchonycteris naso and Saccopteryx bilineata) and three mormoopids Pteronotus parnellii, P. davyi, and P. personatus) were examined acoustically with the Anabat II bat detector and associated analysis system. R. naso used calls consisting of a short constant frequency CF) at 47 kHz and concave downward frequency modulated FM) sweep to about 40 kHz with two strong harmonics. Echolocation sequences of S. bilineata revealed a paired cadence of calls. Both signals in a pair slowly increased in frequency, forming a quasi-CF QCF) component and terminated with a short, downward FM sweep. The initial call of a pair ranged from 44.5 to 46.6 kHz and the second ranged from 46.6 to 48.7 kHz. P. parnellii used a long CF call at 63.5 kHz, with a terminal downward FM sweep to about 54.5 kHz. P. davyi produced calls with an initial short CF at 68.1 kHz, a downward FM sweep, and a terminal short CF at 58.0 kHz. P. personatus emitted calls similar in shape to P. davyi, with the initial CF at 83.0 kHz and the terminal CF at about 68.0 kHz. Previous descriptions of echolocation calls for these species compare favorably with those obtained in this study, but the Anabat equipment generally revealed more variation and detail than previously described. The echolocation calls described in this study provide precise vocal signatures for the accurate identification of free-flying individuals of the species studied.

10aAnabat10abats10aecholocation10aPteronotus davyi10aPteronotus parnellii10aPteronotus personatus10aRhynchonycteris naso10aSaccopteryx bilineata10avocal signatures1 aO'Farrell, Michael, J.1 aMiller, Bruce, W. uhttps://bio.acousti.ca/nn/node/5805302640nas a2200385 4500008004100000245007700041210006900118300001000187490000700197520153100204653001101735653000901746653001501755653001701770653002401787653001901811653003001830653002201860653001701882653001801899653002201917653002201939653002401961653002301985653002202008653002302030653002602053653002602079653001402105653002102119100002702140700002202167700002402189856004102213 1999 eng d00aQualitative Identification of Free-flying Bats Using the Anabat Detector0 aQualitative Identification of Freeflying Bats Using the Anabat D a11-230 v803 a

A variety of ultrasonic bat detectors have been used over the past 3 decades to identify freeflying bats. Analyses of recorded echolocation calls were slow and typically restricted to few calls and at a resolution obscuring details of call structure. The Anabat II detector and associated zerocrossings analysis system allows an immediate examination, via a laptop computer, of the timefrequency structure of calls as they are detected. These calls can be stored on the hard drive for later examination, editing, and measurement. Many North American bats can be identified to species by qualitatively using certain structural characteristics of calls, primarily approximate maximum and minimum frequencies and morphological aspects of calls e.g., linearity and changes in slope). To identify calls precisely, it is important to use a continuous sequence of calls from an individual in normal flight rather than from single isolated calls. All calls are not equally useful, and many fragmentary calls must be discarded before making a determination. Each sequence of calls must be examined to ensure that multiple bats have not been simultaneously recorded, which confounds correct identification. We found the percentage of nonusable calls within usable vocal sequences to be highest in vespertilionids 20-40%), whereas for other families this was frequently <10%. Active rather than passive collection of data maximizes quality and quantity of diagnostic calls and provides a contextual base for the investigator.

10aAnabat10abats10aChiroptera10aecholocation10aEptesicus furinalis10aidentification10aLasionycteris noctivagans10aLasiurus cinereus10aLasiurus ega10aMolossus ater10aMolossus molossus10aMolossus sinaloae10aMyotis californicus10aMyotis ciliolabrum10aMyotis yumanensis10aNoctilio leporinus10aSaccopteryx bilineata10aTadarida brasiliensis10atechnique10avocal signatures1 aO'Farrell, Michael, J.1 aMiller, Bruce, W.1 aGannon, William, L. uhttps://bio.acousti.ca/nn/node/5805101561nas a2200229 4500008004100000245011800041210006900159300001100228490000600239520086300245653002801108653002401136653000701160653001101167653001301178653001501191653001701206653002301223653002201246100002201268856004101290 2001 eng d00aA method for determining relative activity of free flying bats using a new activity index for acoustic monitoring0 amethod for determining relative activity of free flying bats usi a93-1050 v33 a

A new activity index for acoustical bat data is presented. The AI acoustical activity index) was highly correlated to bat passes but proved to be a less biased index of activity. The method dispenses with the need to define, identify and count bat passes and provides a simple means to quantify activity. This method uses the Anabat system where acoustic surveys are carried out in real time with the data saved directly to a computer hard drive, taking advantage of the date-time information encoded into each file. The method is based upon the presence absence of a species occurrence during one-minute time intervals and avoids inflating an index of activity that may reflect the behavior of the species sampled. Examples are given showing that the AI is an effective measure of bat activity allowing comparisons between sites, times and species.

10aacoustic activity index10aacoustic monitoring10aAI10aAnabat10abat pass10aChiroptera10aecholocation10arelative abundance10arelative activity1 aMiller, Bruce, W. uhttps://bio.acousti.ca/nn/node/5805001785nas a2200217 4500008004100000245012800041210006900169520098500238653002201223653001201245653001701257653003401274653001801308653001501326653000801341653002201349653001601371100002001387700002401407856013601431 2019 eng d00aAcoustically estimated size distribution of sperm whales ( Physeter macrocephalus) off the east coast of New Zealand0 aAcoustically estimated size distribution of sperm whales iPhyset3 a

The length-frequency distribution of sperm whales (Physeter macrocephalus) was studied on the east coast of NZ using passive acoustic recorders moored offshore of Kaikoura, Cape Palliser and Castlepoint. Sperm whale’s echolocation signals are unique among odontocete species. Their clicks are composed by multiple pulses resulting from the sound transmission within the whale head. The total length of the whales can be estimated by measuring the time delay between these pulses. A total of 997 length measurements were obtained from click trains using cepstral analysis (mean = 14.6 m; min = 9.6 m; max = 18.3 m; std = 1 m). The size-frequency distributions at all three locations were similar, although animals smaller than 12 m were not present offshore of Kaikoura. Animals of various sizes appeared to be present all year round, with no apparent seasonality in the occurrence of any size class.

10acepstral analysis10aceptrum10aecholocation10alength-frequency distribution10amarine mammal10aodontocete10aPAM10apassive acoustics10asperm whale1 aGiorli, Giacomo1 aGoetz, Kimberly, T. uhttps://www.tandfonline.com/doi/full/10.1080/00288330.2019.1679843https://www.tandfonline.com/doi/pdf/10.1080/00288330.2019.167984302898nas a2200217 4500008004100000245018100041210006900222520208500291653001102376653001702387653001502404653001702419653003202436100002802468700001902496700001902515700002702534700002502561700002702586856006702613 2019 eng d00aStronger together: Combining automated classifiers with manual post-validation optimizes the workload vs reliability trade-off of species identification in bat acoustic surveys0 aStronger together Combining automated classifiers with manual po3 a

Owing to major technological advances, bioacoustics has become a burgeoning field in ecological research worldwide. Autonomous passive acoustic recorders are becoming widely used to monitor aerial insectivorous bats, and automatic classifiers have emerged to aid researchers in the daunting task of analysing the resulting massive acoustic datasets. However, the scarcity of comprehensive reference call libraries still hampers their wider application in highly diverse tropical assemblages. Capitalizing on a unique acoustic dataset of >650,000 bat call sequences collected over a 3-year period in the Brazilian Amazon, the aims of this study were (a) to assess how pre-identified recordings of free-flying and hand-released bats could be used to train an automatic classification algorithm (random forest), and (b) to optimize acoustic analysis protocols by combining automatic classification with visual post-validation, whereby we evaluated the proportion of sound files to be post-validated for different thresholds of classification accuracy. Classifiers were trained at species or sonotype (group of species with similar calls) level. Random forest models confirmed the reliability of using calls of both free-flying and hand-released bats to train custom-built automatic classifiers. To achieve a general classification accuracy of ~85%, random forest had to be trained with at least 500 pulses per species/sonotype. For seven out of 20 sonotypes, the most abundant in our dataset, we obtained high classification accuracy (>90%). Adopting a desired accuracy probability threshold of 95% for the random forest classifier, we found that the percentage of sound files required for manual post-validation could be reduced by up to 75%, a significant saving in terms of workload. Combining automatic classification with manual ID through fully customizable classifiers implemented in open-source software as demonstrated here shows great potential to help overcome the acknowledged risks and biases associated with the sole reliance on automatic classification.

10aAmazon10abioacoustics10aChiroptera10aecholocation10aMachine-learning algorithms1 aLópez-Baucells, Adrià1 aTorrent, Laura1 aRocha, Ricardo1 aBobrowiec, Paulo, E.D.1 aPalmeirim, Jorge, M.1 aMeyer, Christoph, F.J. uhttps://linkinghub.elsevier.com/retrieve/pii/S157495411830023202632nas a2200289 4500008004100000245011000041210006900151520174700220653001501967653002501982653002502007653000902032653001702041653002502058653001002083653001802093653001702111653002102128653002402149653001902173100001502192700001402207700001802221700001402239700002202253856006702275 2019 eng d00aAutomatic standardized processing and identification of tropical bat calls using deep learning approaches0 aAutomatic standardized processing and identification of tropical3 a

Consistent and comparable metrics to automatically monitor biodiversity across the landscape remain a gold-standard for biodiversity research, yet such approaches have frequently been limited to a very small selection of species for which visual approaches (e.g., camera traps) make continuous monitoring possible. Acoustic-based methods have been widely applied in the monitoring of bats and some other taxa across extended spatial scales, but are have yet to be applied to diverse tropical communities.

In this study, we developed a software program “Waveman” and prepared a reference library using over 880 audio-files from 36 Asian bat species. The software incorporated a novel network “BatNet” and a re-checking strategy (ReChk) to maximize accuracy. In Waveman, BatNet outperforms three other published networks: CNNFULL, VggNet and ResNet_v2, with over 90% overall accuracy and 0.94 AUC on the ROC plot. The classification accuracy rates for all 36 species are at least 86% when analysed in combination. Moreover, our library preparation and ReChk greatly improved the sensitivity and reduced the false positive rate, when tested with 15 species for which more detailed and situationally diverse records were available. Finally, BatNet was successfully used to identify Hipposideros larvatus and Rhinolophus siamensis from three different environments. We hope this pipeline is useful tool to process bioacoustic data accurately, effectively and automatically, therefore allowing for greater standardization and comparability for researchers to understand bat activities across space and time and therefore provide a consistent tool for monitoring biodiversity for management and conservation.

10aAlgorithms10aAutomated monitoring10aAutomatic processing10abats10abioacoustics10aBiodiversity metrics10aCalls10aDeep learning10aecholocation10amachine learning10aMonitoring protocol10aNeural network1 aChen, Xing1 aZhao, Jun1 aChen, Yan-hua1 aZhou, Wei1 aHughes, Alice, C. uhttps://linkinghub.elsevier.com/retrieve/pii/S000632071930896101564nas a2200193 4500008004100000245005200041210005200093520101400145653001901159653000901178653001701187653002301204653002301227653001301250100001401263700001301277700001401290856006601304 2019 eng d00aSensory gaze stabilization in echolocating bats0 aSensory gaze stabilization in echolocating bats3 a

Sensing from a moving platform is challenging for both man-made machines and animals. Animals' heads jitter during movement, so if the sensors they carry are not stabilized, any spatial estimation might be biased. Flying animals, like bats, seriously suffer from this problem because flapping flight induces rapid changes in acceleration which moves the body up and down. For echolocating bats, the problem is crucial. Because they emit a sound to sense the world, an unstable head means sound energy pointed in the wrong direction. It is unknown how bats mitigate this problem. By tracking the head and body of flying fruit bats, we show that they stabilize their heads, accurately maintaining a fixed acoustic-gaze relative to a target. Bats can solve the stabilization task even in complete darkness using only echo-based information. Moreover, the bats point their echolocation beam below the target and not towards it, a strategy that should result in better estimations of target elevation.

10aactive sensing10abats10aecholocation10agaze stabilization10asensory perception10atracking1 aEitan, O.1 aKosa, G.1 aYovel, Y. uhttps://royalsocietypublishing.org/doi/10.1098/rspb.2019.149603117nas a2200241 4500008004100000022001300041245018100054210006900235260001600304520208500320653001102405653001702416653001502433653001702448653003202465100002802497700001902525700001902544700002702563700002502590700002702615856023302642 2018 eng d a1574954100aStronger together: Combining automated classifiers with manual post-validation optimizes the workload vs reliability trade-off of species identification in bat acoustic surveys0 aStronger together Combining automated classifiers with manual po cJan-11-20183 a

Owing to major technological advances, bioacoustics has become a burgeoning field in ecological research worldwide. Autonomous passive acoustic recorders are becoming widely used to monitor aerial insectivorous bats, and automatic classifiers have emerged to aid researchers in the daunting task of analysing the resulting massive acoustic datasets. However, the scarcity of comprehensive reference call libraries still hampers their wider application in highly diverse tropical assemblages. Capitalizing on a unique acoustic dataset of >650,000 bat call sequences collected over a 3-year period in the Brazilian Amazon, the aims of this study were (a) to assess how pre-identified recordings of free-flying and hand-released bats could be used to train an automatic classification algorithm (random forest), and (b) to optimize acoustic analysis protocols by combining automatic classification with visual post-validation, whereby we evaluated the proportion of sound files to be post-validated for different thresholds of classification accuracy. Classifiers were trained at species or sonotype (group of species with similar calls) level. Random forest models confirmed the reliability of using calls of both free-flying and hand-released bats to train custom-built automatic classifiers. To achieve a general classification accuracy of ~85%, random forest had to be trained with at least 500 pulses per species/sonotype. For seven out of 20 sonotypes, the most abundant in our dataset, we obtained high classification accuracy (>90%). Adopting a desired accuracy probability threshold of 95% for the random forest classifier, we found that the percentage of sound files required for manual post-validation could be reduced by up to 75%, a significant saving in terms of workload. Combining automatic classification with manual ID through fully customizable classifiers implemented in open-source software as demonstrated here shows great potential to help overcome the acknowledged risks and biases associated with the sole reliance on automatic classification.

10aAmazon10abioacoustics10aChiroptera10aecholocation10aMachine-learning algorithms1 aLópez-Baucells, Adrià1 aTorrent, Laura1 aRocha, Ricardo1 aBobrowiec, Paulo, E.D.1 aPalmeirim, Jorge, M.1 aMeyer, Christoph, F.J. uhttps://linkinghub.elsevier.com/retrieve/pii/S1574954118300232https://api.elsevier.com/content/article/PII:S1574954118300232?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S1574954118300232?httpAccept=text/plain03094nas a2200397 4500008004100000022001300041245005700054210005700111260001600168520180000184653000801984653002301992653001702015653001302032653000802045653002102053653001502074653001702089100002202106700002202128700001802150700001902168700001602187700002502203700003402228700002402262700002302286700001602309700001802325700002602343700002602369700002602395700002502421700001702446856023302463 2018 eng d a0960982200aResource Ephemerality Drives Social Foraging in Bats0 aResource Ephemerality Drives Social Foraging in Bats cJan-11-20183 a

Observations of animals feeding in aggregations are often interpreted as events of social foraging, but it can be difficult to determine whether the animals arrived at the foraging sites after collective search [1, 2, 3, 4] or whether they found the sites by following a leader [5, 6] or even independently, aggregating as an artifact of food availability [7, 8]. Distinguishing between these explanations is important, because functionally, they might have very different consequences. In the first case, the animals could benefit from the presence of conspecifics, whereas in the second and third, they often suffer from increased competition [3, 9, 10, 11, 12, 13]. Using novel miniature sensors, we recorded GPS tracks and audio of five species of bats, monitoring their movement and interactions with conspecifics, which could be inferred from the audio recordings. We examined the hypothesis that food distribution plays a key role in determining social foraging patterns [14, 15, 16]. Specifically, this hypothesis predicts that searching for an ephemeral resource (whose distribution in time or space is hard to predict) is more likely to favor social foraging [10, 13, 14, 15] than searching for a predictable resource. The movement and social interactions differed between bats foraging on ephemeral versus predictable resources. Ephemeral species changed foraging sites and showed large temporal variation nightly. They aggregated with conspecifics as was supported by playback experiments and computer simulations. In contrast, predictable species were never observed near conspecifics and showed high spatial fidelity to the same foraging sites over multiple nights. Our results suggest that resource (un)predictability influences the costs and benefits of social foraging.

10abat10abehavioral ecology10aecholocation10aforaging10aGPS10amovement ecology10anavigation10asociobiology1 aEgert-Berg, Katya1 aHurme, Edward, R.1 aGreif, Stefan1 aGoldstein, Aya1 aHarten, Lee1 aM., Luis, Gerardo He1 aFlores-Martínez, José, Juan1 aValdés, Andrea, T.1 aJohnston, Dave, S.1 aEitan, Ofri1 aBorissov, Ivo1 aShipley, Jeremy, Ryan1 aMedellin, Rodrigo, A.1 aWilkinson, Gerald, S.1 aGoerlitz, Holger, R.1 aYovel, Yossi uhttps://linkinghub.elsevier.com/retrieve/pii/S0960982218312909https://api.elsevier.com/content/article/PII:S0960982218312909?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0960982218312909?httpAccept=text/plain02880nas a2200313 4500008004100000022001300041245008700054210006900141260001600210300001400226490000800240520197300248653001002221653001802231653001702249653001502266653001702281653002002298653002402318653002302342653000902365100002302374700002302397700002302420700002102443700001602464700002002480856006602500 2017 eng d a0003347200aSilent porpoise: potential sleeping behaviour identified in wild harbour porpoises0 aSilent porpoise potential sleeping behaviour identified in wild  cJan-11-2017 a211 - 2220 v1333 a

All animals sleep and it is essential for maintaining optimal brain function. However, cetaceans engage in the unusual practice of unihemispherical sleep, where only half of their brain sleeps at a time, due to their constant need for movement and breathing. Most studies of sleep in cetaceans have occurred in captivity. However, tagging devices have now developed to the point where the data collected from wild animals can be assessed against published criteria for defining sleep behaviourally. Seven acoustic and behavioural data loggers were deployed on harbour porpoises, Phocoena phocoena, in Danish waters between May 2010 and August 2011 and stayed on the animals between 53 and 72 h, recording 1884 to 2755 valid dives per animal. Parabolic dives with significantly reduced bioacoustic activity and a ste- reotyped behavioural pattern were identified as potential sleeping periods. The recordings for nearly half of the parabolic dives were found to contain no vocalization (echolocation clicks), significantly more than other dive types. Of the remaining parabolic dives, the click rate was, when normalized to their indi- vidual means, also significantly lower than detected in other dive types. Additionally, parabolic dives were shallow compared to all other dive types, and found to have a stereotypic low-energy profile. They were also found to contain fewer rolls and incorporate a lower vertical descent rate than most other dive types. If the data are representative, harbour porpoises spend a small, but meaningful amount of their diving time engaged in parabolic dives and thus potentially sleeping. All animals have a fundamental need for undisturbed sleep. These quiet periods thus need to be considered in studies of anthropogenic effects, but also those employing passive acoustic monitoring techniques, as well as in efforts to reduce incidental bycatch in fisheries, given the associated periods of reduced environmental awareness.

10aA-tag10aacoustic tags10adata storage10ae Phocoena10aecholocation10aharbour porpois10asatellite telemetry10asleeping behaviour10atags1 aWright, Andrew, J.1 aAkamatsu, Tomonari1 aMouritsen, Kim, N.1 aSveegaard, Signe1 aDietz, Rune1 aTeilmann, Jonas uhttp://linkinghub.elsevier.com/retrieve/pii/S000334721730302003163nas a2200277 4500008004100000022001300041245009800054210006900152260001600221300001400237490000800251520229700259653002702556653000902583653001402592653001602606653001802622653001702640653004202657653003802699653001802737653002102755100001802776700002502794856006602819 2017 eng d a0003347200aTo seek or speak? Dual function of an acoustic signal limits its versatility in communication0 aTo seek or speak Dual function of an acoustic signal limits its  cJan-05-2017 a135 - 1520 v1273 a

The perception of different attributes of conspecifics is an integral part of intraspecific communication. It can facilitate the recognition of interaction partners or the assessment of potential mates. Acoustic signals can encode fine-scaled information through the interplay of acoustic variability and specificity. A reliable vocal signature is both unique within a class and variable between classes. Therefore, acoustic complexity might be associated with the number of classes to be discriminated. We investigated the assumption that limitations to signal design may affect the communicative functionality of a signal. To do so, we chose a signal with potentially dual functionality which may therefore display such limitations. In bats, echolocation is used primarily for foraging and orientation but there is increasing support for its additional role in communication. An acoustic analysis of echolocation pulses of the bat Rhinolophus clivosus confirmed sex and individual vocal signatures in echolocation pulses. A habituation–dishabituation playback experiment suggested that bats perceived these signatures because listening bats clearly discriminated between the sexes (two classes) and between individuals (representatives of a multiclass category), although to different degrees. The simple acoustic structure of these vocalizations provides sufficient specificity for sex discrimination but has limitations for individual discrimination because pulse parameters of individuals increasingly overlapped with increasing group size. We conclude that selection for the primary function of echolocation restricts the acoustic space available for communication. However, we frequently observed echolocation pulses with conspicuous structural modifications. Statistical analyses revealed that these vocalizations yielded increased individual distinctiveness. Such added systematic variation may indicate a communicative function and perhaps a signalling intent of the emitter, although the latter has yet to be tested. The findings suggest that the required specificity for effective communication could be obtained through modification of echolocation variants when adaptations for orientation and foraging constrain the evolution of complex communication signatures.

10aacoustic communication10abats10aco-option10aconstraints10aeavesdropping10aecholocation10ahabituation–dishabituation playback10aindividual and sex discrimination10asignal design10avocal signatures1 aBastian, Anna1 aJacobs, David, Steve uhttp://linkinghub.elsevier.com/retrieve/pii/S000334721730077502456nas a2200229 4500008004100000245007100041210006900112260001600181490000600197520170600203653002701909653001801936653001701954653001701971653003201988653003202020653001702052100003102069700002502100700002402125856007702149 2013 eng d00aInterspecific acoustic recognition in two European bat communities0 aInterspecific acoustic recognition in two European bat communiti cJan-01-20130 v43 a

Echolocating bats emit echolocation calls for spatial orientation and foraging. These calls are often species-specific and are emitted at high intensity and repetition rate. Therefore, these calls could potentially function in intra- and/or inter-specific bat communication. For example, bats in the field approach playbacks of conspecific feeding buzzes, probably because feeding buzzes indicate an available foraging patch. In captivity, some species of bats recognize and distinguish the echolocation calls of different sympatric species. However, it is still unknown if and how acoustic species-recognition mediates interspecific interactions in the field. Here we aim to understand eavesdropping on bat echolocation calls within and across species boundaries in wild bats. We presented playbacks of conspecific and heterospecific search calls and feeding buzzes to four bat species with different foraging ecologies. The bats were generally more attracted by feeding buzzes than search calls and more by the calls of conspecifics than their heterospecifics. Furthermore, bats showed differential reaction to the calls of the heterospecifics. In particular, <i>Myotis capaccinii</i> reacted equally to the feeding buzzes of conspecifics and to ecologically more similar heterospecifics. Our results confirm eavesdropping on feeding buzzes at the intraspecific level in wild bats and provide the first experimental quantification of potential eavesdropping in European bats at the interspecific level. Our data support the hypothesis that bat echolocation calls have a communicative potential that allows interspecific, and potentially intraspecific, eavesdropping in the wild.

10aacoustic communication10aeavesdropping10aecholocation10afeeding buzz10ainterspecific communication10aintraspecific communication10asearch calls1 aDorado-Correa, Adriana, M.1 aGoerlitz, Holger, R.1 aSiemers, Björn, M. uhttp://journal.frontiersin.org/article/10.3389/fphys.2013.00192/abstract02235nas a2200241 4500008004100000022001400041245011700055210006900172260002000241490000700261520140700268653001701675653001301692653001901705653002001724653002501744100001201769700001501781700001501796700002001811700002101831856014101852 2013 eng d a1742-568900aGlobal warming alters sound transmission: differential impact on the prey detection ability of echolocating bats0 aGlobal warming alters sound transmission differential impact on  cFeb-07-201321840 v113 a

Climate change impacts the biogeography and phenology of plants and ani- mals, yet the underlying mechanisms are little known. Here, we present a functional link between rising temperature and the prey detection ability of echolocating bats. The maximum distance for echo-based prey detection is physically determined by sound attenuation. Attenuation is more pronoun- ced for high-frequency sound, such as echolocation, and is a nonlinear function of both call frequency and ambient temperature. Hence, the prey detection ability, and thus possibly the foraging efficiency, of echolocating bats and susceptible to rising temperatures through climate change. Using present-day climate data and projected temperature rises, we modelled this effect for the entire range of bat call frequencies and climate zones around the globe. We show that depending on call frequency, the prey detection volume of bats will either decrease or increase: species calling above a cross- over frequency will lose and species emitting lower frequencies will gain prey detection volume, with crossover frequency and magnitude depending on the local climatic conditions. Within local species assemblages, this may cause a change in community composition. Global warming can thus directly affect the prey detection ability of individual bats and indirectly their interspecific interactions with competitors and prey.

10aecholocation10aforaging10aglobal warming10asensory ecology10aspecies interactions1 aLuo, J.1 aKoselj, K.1 aZsebok, S.1 aSiemers, B., M.1 aGoerlitz, H., R. uhttp://rsif.royalsocietypublishing.org/cgi/doi/10.1098/rsif.2013.0961https://syndication.highwire.org/content/doi/10.1098/rsif.2013.096101826nas a2200217 4500008004100000022001400041245004200055210004100097260002000138300002400158490000600182520116800188653001401356653000901370653001701379653001501396653001601411100001901427700002101446856014101467 2013 eng d a1744-956100aHawkmoths produce anti-bat ultrasound0 aHawkmoths produce antibat ultrasound cNov-20-20132082 a20130161 - 201301610 v93 a

Bats and moths have been engaged in aerial warfare for nearly 65 Myr. This arms race has produced a suite of counter-adaptations in moths, including bat-detecting ears. One set of defensive strategies involves the active production of sound; tiger moths' ultrasonic replies to bat attack have been shown to startle bats, warn the predators of bad taste and jam their biosonar. Here, we report that hawkmoths in the Choerocampina produce entirely ultrasonic sounds in response to tactile stimulation and the playback of biosonar attack sequences. Males do so by grating modified scraper scales on the outer surface of the genital valves against the inner margin of the last abdominal tergum. Preliminary data indicate that females also produce ultrasound to touch and playback of echolocation attack, but they do so with an entirely different mechanism. The anti-bat function of these sounds is unknown but might include startling, cross-family acoustic mimicry, warning of unprofitability or physical defence and/or jamming of echolocation. Hawkmoths present a novel and tractable system to study both the function and evolution of anti-bat defences.

10aarms race10abats10aecholocation10aSphingidae10asphinx moth1 aBarber, J., R.1 aKawahara, A., Y. uhttp://rsbl.royalsocietypublishing.org/cgi/doi/10.1098/rsbl.2013.0161https://syndication.highwire.org/content/doi/10.1098/rsbl.2013.016102009nas a2200205 4500008004100000022001400041245011700055210006900172260001600241300001400257490000800271520132200279653001401601653001701615653003301632653001501665100001601680700002201696856008501718 2017 eng d a0024-406600aHearing sensitivity is more relevant to acoustic conspicuousness than to mechanical constraints in crambid moths0 aHearing sensitivity is more relevant to acoustic conspicuousness cMay-08-2017 a174 - 1840 v1213 a

Moths evolved tympanal hearing organs to detect the echolocation calls of predatory bats. Moths’ auditory responses have been examined mainly for their sensitivity to the frequencies of bat cries: tympanate moths are basically tuned to the call frequencies of sympatric bats. Here, we add the finding that hearing sensitivity to ‘pulse duration’ in cram- bid moths is also affected by predation pressure from echolocating bats. Analysis of interspecific variation showed that minimum auditory thresholds had a significantly negative relationship with the forewing surface area, that is, acoustic conspicuousness to bat sonar, but no relationship with head width, which was assumed to correlate with tympanal organ size. Auditory thresholds increased as pulses shortened in the 1–10 ms duration range, and conspic- uous moths with larger wing areas had lower thresholds than smaller moths. By contrast, ‘intraspecific’ variation, within a single population of the lurcerne moth, revealed no relationship between forewing area and any auditory characteristics. Moth hearing adapts to the echolocation pulse duration of sympatric bat communities, suggesting that evolutionary modification of hearing sensitivity is related to acoustic conspicuousness based on moth wing area.

10aarms race10aecholocation10apredator–prey interactions10aultrasound1 aNakano, Ryo1 aMason, Andrew, C. uhttps://academic.oup.com/biolinnean/article-lookup/doi/10.1093/biolinnean/blw02903163nas a2200277 4500008004100000022001300041245009800054210006900152260001600221300001400237490000800251520229700259653002702556653000902583653001402592653001602606653001802622653001702640653004202657653003802699653001802737653002102755100001802776700002502794856006602819 2017 eng d a0003347200aTo seek or speak? Dual function of an acoustic signal limits its versatility in communication0 aTo seek or speak Dual function of an acoustic signal limits its  cJan-05-2017 a135 - 1520 v1273 a

The perception of different attributes of conspecifics is an integral part of intraspecific communication. It can facilitate the recognition of interaction partners or the assessment of potential mates. Acoustic signals can encode fine-scaled information through the interplay of acoustic variability and specificity. A reliable vocal signature is both unique within a class and variable between classes. Therefore, acoustic complexity might be associated with the number of classes to be discriminated. We investigated the assumption that limitations to signal design may affect the communicative functionality of a signal. To do so, we chose a signal with potentially dual functionality which may therefore display such limitations. In bats, echolocation is used primarily for foraging and orientation but there is increasing support for its additional role in communication. An acoustic analysis of echolocation pulses of the bat Rhinolophus clivosus confirmed sex and individual vocal signatures in echolocation pulses. A habituation–dishabituation playback experiment suggested that bats perceived these signatures because listening bats clearly discriminated between the sexes (two classes) and between individuals (representatives of a multiclass category), although to different degrees. The simple acoustic structure of these vocalizations provides sufficient specificity for sex discrimination but has limitations for individual discrimination because pulse parameters of individuals increasingly overlapped with increasing group size. We conclude that selection for the primary function of echolocation restricts the acoustic space available for communication. However, we frequently observed echolocation pulses with conspicuous structural modifications. Statistical analyses revealed that these vocalizations yielded increased individual distinctiveness. Such added systematic variation may indicate a communicative function and perhaps a signalling intent of the emitter, although the latter has yet to be tested. The findings suggest that the required specificity for effective communication could be obtained through modification of echolocation variants when adaptations for orientation and foraging constrain the evolution of complex communication signatures.

10aacoustic communication10abats10aco-option10aconstraints10aeavesdropping10aecholocation10ahabituation–dishabituation playback10aindividual and sex discrimination10asignal design10avocal signatures1 aBastian, Anna1 aJacobs, David, Steve uhttp://linkinghub.elsevier.com/retrieve/pii/S0003347217300775