02274nas a2200241 4500008004100000022001400041245009400055210006900149260001600218300001500234520143200249653000901681653002001690653001301710653002101723653001001744653000901754100001701763700002401780700002101804700002101825856018601846 2019 eng d a0022-094900aNoise as an informational cue for decision-making: the sound of rain delays bat emergence0 aNoise as an informational cue for decisionmaking the sound of ra cSep-01-2020 ajeb.1920053 a

Background noise can have strong negative consequences on animals, reducing individual fitness by masking communication signals, impeding prey detection and increasing predation risk. While the negative impacts of noise across taxa have been well documented, the use of noise as an informational cue, providing animals with reliable information on environmental conditions has been less well studied. In the tropical rainforest, downpours can be intense and frequent. Strong rainfall may impede efficient orientation and foraging for bats that need echolocation to both navigate and detect prey, and can result in higher flight costs due to increased metabolic rates. Using playback experiments at natural roosts we tested whether two bat species, differing in their hunting strategies and foraging habitats, use rain noise as a cue to delay emergence from their roosts. We found that both species significantly delayed their emergence time during rain noise playbacks compared to silence and ambient noise controls. We conclude that bats can use background noise, here the acoustic component of rainfall, as a reliable informational cue to make informed decisions, here about whether to initiate foraging trips or remain in the shelter of their roosts. Our findings suggest that environmental background noise can sometimes be beneficial to animals, in particular in situations where other sensory cues may be absent.

10abats10adecision-making10aforaging10ainformation cues10aNoise10arain1 aGeipel, Inga1 aSmeekes, Marcus, J.1 aHalfwerk, Wouter1 aPage, Rachel, A. uhttp://jeb.biologists.org/lookup/doi/10.1242/jeb.192005https://syndication.highwire.org/content/doi/10.1242/jeb.192005https://syndication.highwire.org/content/doi/10.1242/jeb.19200502261nas a2200229 4500008004100000245009200041210006900133260001600202520158200218653000901800653001301809653001701822653003001839100001601869700001201885700002001897700001501917700002001932700001401952700001601966856004901982 2018 eng d00aSocial vocalizations of big-footed myotis (Myotis macrodactylus) during foraging0 aSocial vocalizations of bigfooted myotis iMyotis macrodactylusi  cFeb-12-20203 a

Acoustic signals play a crucial role in transmitting information and maintaining social stability in gregarious animals, especially in echolocating bats which rely primarily on biological sonar for navigating in the dark. In the context of foraging without relying on tactile, visual, or olfactory cues, acoustic signals convey information not only on food, but also on ownership and defense of resources. However, studies on such information remain fragmentary. In the present study, we aim to document the social vocal repertoire of Myotis macrodactylus at natural foraging sites. Multiple acoustic analyses and spectrographic classification revealed a rich foraging vocal repertoire comprising 6 simple syllables and 2 composites. Discriminant function analyses associated with a subset‐validation procedure provided an optimal method to spectrographically classify all recorded sounds into different syllable types. Multidimensional scaling of median values of multiple parameters further confirmed notable differences among these syllables in a three‐dimensional space. In addition, Euclidean distance analysis showed that there were some spectral similarities between specific social vocal syllables and feeding buzzes, which implied a potential jamming role. Altogether, the data indicate that bats at foraging sites under natural conditions used variant social vocalizations with different functions in addition to echolocation calls, providing supporting evidence for further work on the function and vocal mechanisms of acoustic communication in mammals.

10abats10aforaging10aSocial calls10aSpectro-temporal features1 aGuo, Dongge1 aLuo, Bo1 aZhang, Kangkang1 aLIU, Muxun1 aMetzner, Walter1 aLiu, Ying1 aFeng, Jiang uhttp://doi.wiley.com/10.1111/1749-4877.1236702209nas a2200241 4500008004100000022001300041245006600054210006500120260001600185300001200201490000800213520132800221653002001549653001301569653002001582653001701602653002801619653001801647100002601665700002201691700002101713856023301734 2018 eng d a0003347200aCognitive constraints on optimal foraging in frog-eating bats0 aCognitive constraints on optimal foraging in frogeating bats cJan-09-2018 a43 - 500 v1433 a

Animals are expected to optimize energy intake when choosing between different foraging options. A common explanation for deviations from optimal economic decisions is that there is an imperfect relationship between physical reality and an animal's perceptual processes, which can constrain assessment of profitability. One such phenomenon that is apparently ubiquitous across taxa is proportional processing, where a perceived change in a stimulus is proportional to the change in stimulus magnitude. In this study, we investigated whether proportional processing explains how frog-eating bats, Trachops cirrhosus, discriminate between patches of frog choruses that vary in their number of calling frogs. To test this, we created artificial choruses consisting of one to six calling frogs. In the flight cage, we then tested the preference of bats (N = 17) with every pairwise combination of chorus size. We found that while bats generally preferred larger choruses, preferences for larger choruses were better explained by the relative, not absolute, differences in chorus sizes. This indicates that T. cirrhosus is perceptually limited in its ability to discriminate between choruses of varying size as the choruses increase in size. Foragers are likely to be less choosy when choosing among larger patches.

10aDecision making10aforaging10afrog-eating bat10apatch choice10aproportional processing10atúngara frog1 aHemingway, Claire, T.1 aRyan, Michael, J.1 aPage, Rachel, A. uhttps://linkinghub.elsevier.com/retrieve/pii/S0003347218302227https://api.elsevier.com/content/article/PII:S0003347218302227?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003347218302227?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/plain02313nas a2200277 4500008004100000022001300041245008800054210006900142260001600211300001400227490000800241520150900249653002701758653000901785653003701794653001301831653001601844100001201860700001601872700001601888700001601904700001901920700001401939700001601953856006601969 2017 eng d a0003347200aSocial calls honestly signal female competitive ability in Asian particoloured bats0 aSocial calls honestly signal female competitive ability in Asian cJan-05-2017 a101 - 1080 v1273 a

Why a variety of social animals vocalize during agonistic foraging interactions remains obscure. One possibility is that these signals advertise the signaller's competitive ability, playing a role in the defence of food resources, yet there is limited evidence in support of this idea. Here, we used adult female Asian particoloured bats, Vespertilio sinensis, to test whether individual variation in competitive ability when foraging can be explained by social calls. Using synchronized infrared video and audio recording, we monitored bat social vocalizations, dominance rank and weight gain in triads under controlled food conditions. Additionally, subsequent playbacks, consisting of experimental stimuli, echolocation pulses and silence, were presented to feeding bats in a laboratory. Analyses showed that females uttered low-frequency social calls composed of one to five syllable types during feeding competition. The rates of social vocalizations increased with reduced food availability. Interestingly, dominance score and weight gain correlated weakly with body size, but positively with call rate and associated parameters. Playback of social calls inhibited the visits of bats to the focal food dish compared to playback of silence and echolocation pulses. The amount of food consumed was greatly reduced in the presence of experimental stimuli versus controls. Collectively, these results highlight that acoustic signals serve as an honest indicator of bat competitive ability.

10aaggressive interaction10abats10acompetitive ability echolocation10aforaging10asocial call1 aLuo, Bo1 aLu, Guanjun1 aChen, Kelly1 aGuo, Dongge1 aHuang, Xiaobin1 aLiu, Ying1 aFeng, Jiang uhttp://linkinghub.elsevier.com/retrieve/pii/S000334721730084202540nas a2200241 4500008004100000022001400041245010300055210006900158260001600227300001600243490000800259520175600267653001302023653002302036653001302059653001202072653001902084653002002103100002102123700001402144700002002158856012002178 2008 eng d a0022-094900aCues for acoustic detection of prey: insect rustling sounds and the influence of walking substrate0 aCues for acoustic detection of prey insect rustling sounds and t cJan-09-2008 a2799 - 28060 v2113 a

When insects walk, they generally produce sounds. These can reveal the walkers' presence and location to potential predators such as owls, bats and nocturnal primates. Additionally, predators might extract information on taxon, palatability, size or profitability from the rustling sounds. In contrast to ear morphology, hearing physiology and psychoacoustics of acoustically oriented predators, little attention has hitherto been paid to the acoustic structure and information content of prey sounds. An important element in the ecology of acoustic prey detection remained virtually unexplored: the influence of the substrate type on rustling sounds. In this study, we analysed amplitude and frequency parameters from insects walking on various natural substrates, in both Germany (Carabus beetles) and Madagascar (various beetles and cockroaches). The data show that rustling sound amplitude and frequency content depend on substrate type. On moist substrates arthropods produced less intense and less broadband rustling sounds than on dry substrates. Sound pressure level was reduced by about 6 dB, halving the detection range for the predator. For a given insect, rustling sound amplitude increased with walking speed. Finally, we found that the previously established correlation of arthropod size and rustling amplitude holds across multiple substrates. Based on these data, we provide for the first time estimates of realistic detection distances in the field. These distances range from below 1 m to over 13 m, depending on the substrate, insect mass, walking speed and background noise level. These estimates are crucial for an understanding of the foraging ecology, foraging efficiency and sensory ecology of acoustic predators.

10aauditory10adetection distance10aforaging10ahearing10aprey detection10asensory ecology1 aGoerlitz, H., R.1 aGreif, S.1 aSiemers, B., M. uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.019596https://syndication.highwire.org/content/doi/10.1242/jeb.01959602235nas 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.2013.096102288nas a2200205 4500008004100000022001400041245011600055210006900171260001600240490000700256520164800263653001301911653001601924653001901940653001301959653001901972100002101991700002002012856005002032 2007 eng d a0269-846300aSensory ecology of prey rustling sounds: acoustical features and their classification by wild Grey Mouse Lemurs0 aSensory ecology of prey rustling sounds acoustical features and  cJan-02-20070 v213 a

1. Predatory mammals and birds from several phylogenetic lineages use prey rustling sounds to detect and locate prey. However, it is not known whether these rustling sounds convey information about the prey, such as its size or profitability, and whether predators use them to classify prey accordingly.

2. We recorded rustling sounds of insects in Madagascar walking on natural substrate and show a clear correlation between insect mass and several acoustic parameters.

3. In subsequent behavioural experiments in the field, we determined whether nocturnal animals, when foraging for insects, evaluate these parameters to classify their prey. We used field-experienced Grey Mouse Lemurs Microcebus murinus in short-term captivity. Mouse Lemurs are generally regarded as a good model for the most ancestral primate condition. They use multimodal sensorial information to find food (mainly fruit, gum, insect secretions and arthropods) in nightly forest. Acoustic cues play a role in detection of insect prey.

4. When presented with two simultaneous playbacks of rustling sounds, lemurs spontaneously chose the one higher above their hearing threshold, i.e. they used the rustling sound's amplitude for classification. We were not able, despite attempts in a reinforced paradigm, to persuade lemurs to use cues other than amplitude, e.g. frequency cues, for prey discrimination.

5. Our data suggests that Mouse Lemurs, when foraging for insects, use the mass–amplitude correlation of prey-generated rustling sounds to evaluate the average mass of insects and to guide their foraging decisions.

10aforaging10aprey choice10aprey selection10aprimates10asize selection1 aGoerlitz, H., R.1 aSiemers, B., M. uhttp://www.blackwell-synergy.com/toc/fec/21/1