01757nas a2200097 4500008004100000245004900041210004700090520145100137100002101588856005001609 2003 eng d00aBats and moths: what is there left to learn?0 aBats and moths what is there left to learn3 a

Over 14 families of moths have ears that are adapted to detect the ultrasonic echolocation calls of bats. On hearing a bat, these moths respond with an escape response that reduces their chances of being caught. As an evolutionary response, bats may then have evolved behavioural strategies or changes in call design to overcome the moth's hearing. The nature of this interaction is reviewed. In particular, the role of the echolocation calls of bats in the shaping of the structure, neurophysiology and behavioural responses of moths is discussed. Unresolved issues, such as the structural complexity of the moth's auditory system, the nature of temporal integration and the role of the non‐auditory B cell, are described. Issues in which the interactions between bats and moths may be of more general interest to biologists, such as noise filtering within the central nervous system, protean behaviours and coevolution between predator and prey, are also discussed. The interaction between bats and moths has much to interest general biologists, and may provide a useful model in understanding the neurophysiological basis of behaviour, including protean escape behaviours. The validity of the term coevolution as applied to this system is discussed, as there is no doubt that the auditory system of moths is a response to the echolocation calls of bats, although the evolutionary response of bats to moths is more ambiguous.

1 aWaters, Dean, A. uhttp://www.blackwell-synergy.com/toc/pen/28/405028nas a2200121 4500008004100000245003200041210003000073520469600103100002104799700002204820700002304842856004104865 2014 eng d00aBe loved, be prey, be eaten0 aBe loved be prey be eaten3 a

Animal communication is one of the most fundamental of all social behaviors. It modulates interactions among neighbors and strangers, siblings and parents, and individuals and their prospective mates. One of the most fundamental functions of communication is to enhance the sender’s conspicuousness, to cause the sender to stand out against the background so it can be detected by the receiver. This is a challenge for signals that function over long distances, such as those that function in territorial advertisement and mate attraction, because signal intensity and fidelity decrease with distance from the sender. At longer distances a signal is less likely to be above the receiver’s threshold for detection and recognition, and it is also more likely to be masked by noise as the intensity of noise at the receiver is independent of its distance from the sender.

Another type of noise is generated by conspecifics signaling in the same channel. We may perceive a chorus of frogs or insects as a melodious, even co- operative unit. But to members of the chorus the calls of their neighbors are every bit as deleterious to their own call’s ability to be detected as is environ- mental noise. There is also “noise” within the perceptual systems of the receiver that ameliorates signal detection. One example is habituation. Upon continual exposure to a signal, an animal will tend to ignore it, and some of the animal’s neurons will cease to fire. Another type of perceptual noise is incremental forgetting of a signal once it is perceived. Some signals are more memorable than others, surviving longer in the receiver’s memory. The importance of conspecific noise and perceptual noise is usually less appreciated in animal communication studies than is environmental noise.

Selection often will favor senders to produce communication signals that stand out against these three types of background noise. Conspicuousness is accomplished in a variety of ways. In the acoustic domain animals can use fre- quency bands that contain less noise; they can call longer, at a faster rate, or at a higher amplitude; they can call during periods when others are silent; and they can produce calls that are more complex. Visual signals can stand out more against background when their spectral properties and spatial patterns differ from those in the background, when colors are brighter and patterns are more complex, and when motion patterns associated with the signal, such as push-up displays in lizards, are different than the pattern of background movement, such as vegetation being blow in the wind (e.g., Fleishman, 1992). Increasing signal complexity in both the acoustic and visual domains can to some extent remedy the receiver habituating to and forgetting a signal. There is less known about how chemical, tactile, and electrical signals can enhance contrast with the background.

In a survey of preferences for sexual signals, Michael Ryan and Anne Keddy-Hector (1992) showed that across modalities prospective mates tended to prefer sexual signals that were greater in magnitude: longer and louder, faster and brighter, more complex and with more background contrast. Although there were numerous cases in which prospective mates preferred signals that were near the population mean, there were few cases in which there was a preference for signals of lesser magnitude. A simple rule of thumb for sexual signals is that more is better. Selection for signal efficacy, however, creates a dilemma for the sender: the curse of unintended receivers. In general, each signal has evolved under selection to communi- cate with a specific intended receiver. In the case of sexual advertisement sig- nals, the intended receivers are prospective mates, usually female conspecifics. Other receivers can also detect and respond to signals even if there was no selection on the sender to communicate with them. We refer to these receivers as eavesdroppers or unintended receivers. It is important to note that the terms intended and unintended should not imply intention- ality but instead refer to hypotheses about the selection forces that favored the evolution of these signals. With few exceptions, senders and receivers do not communicate in a private channel. The world is populated by unin- tended receivers, eavesdroppers who are attendant to the signals of senders, often to the demise of senders. In this chapter we explore the tension that exists in sexual communication systems between being conspicuous to potential mates and attracting eavesdroppers, between being loved, being prey, and being eaten.

1 aPage, Rachel, A.1 aRyan, Michael, J.1 aBernal, Ximena, E. uhttps://bio.acousti.ca/de/node/5755501618nas a2200181 4500008004100000022001400041245005500055210005500110260001600165300001600181490000800197520109600205100002101301700001801322700002601340700001901366856005101385 2018 eng d a0001-496600aStealthy moths avoid bats with acoustic camouflage0 aStealthy moths avoid bats with acoustic camouflage cJan-09-2018 a1742 - 17420 v1443 a

Intense predation pressure from echolocating bats has led to the evolution of a host of anti-bat defences in nocturnal moths. Some have evolved ears to detect the ultrasonic biosonar of bats, yet there are many moths that are completely deaf. To enhance their survival chances, deaf moths must instead rely on passive defences. Here, we show that furry morphological specializations give moth bodies and wing joints acoustic stealth by reducing their echoes from bat calls. Using acoustic tomography, echo strength was quantified in the spatial and frequency domains of two deaf moth species that are subject to bat predation and two butterfly species that are not. Thoracic fur determines acoustic camouflage of moths but not butterflies. Thoracic fur provides substantial acoustic stealth at all ecologically relevant ultrasonic frequencies, with fur removal increasing a moth’s detection risk by as much as 38%. The thorax fur of moths acts as a lightweight porous sound absorber, facilitating acoustic camouflage and offering a significant survival advantage against bats.

1 aNeil, Thomas, R.1 aShen, Zhiyuan1 aDrinkwater, Bruce, W.1 aRobert, Daniel uhttp://asa.scitation.org/doi/10.1121/1.506772502202nas a2200157 4500008004100000245009000041210006900131260001600200520166600216100003201882700002501914700001801939700002501957700002101982856004102003 2018 eng d00aCatching insects while recording bats: impacts of light trapping on acoustic sampling0 aCatching insects while recording bats impacts of light trapping  cApr-01-20203 a

Collecting information on bat prey availability usually involves the use of light traps to capture moths and flies that constitute the main prey items of most insectivorous bats. However, despite the recent awareness on the adverse effects of light on bats, little is known regarding the potential impacts of light trapping on the bat sampling outcomes when passive acoustic sampling and light trap- ping are implemented simultaneously. Using a before–after experimental design that involved the installation of a 6 W actinic light trap 1 m away from the bat detector, we tested the predictions that (1) slow-flying bat species will be less active when the light trap is present, while the opposite will be true for fast-fly- ing species; and (2) bat species richness will be lower at lit conditions compared to dark ones. Our results suggest that the use of light traps in combination with bat detectors may considerably influence the outcomes of acoustic sampling. Although the activity of fast-flying bat species did not differ between the two treatments, we found that the activity of slow-flying ones such as Rhinolophus ferrumequinum and Rhinolophus hipposideros decreased significantly at lit condi- tions. Furthermore, we recorded fewer bat species when the light trap was deployed. To overcome this issue, we strongly recommend either (1) placing light traps at a considerable distance from bat detectors; or (2) using light traps during the night that follows the bat sampling if sampling needs to be at the same position; or (3) deploying non-attractant insect traps such as Malaise traps if Lepidoptera is not the main order targeted.

1 aFroidevaux, Jérémy, S. P.1 aFialas, Penelope, C.1 aJones, Gareth1 aPettorelli, Nathalie1 aMerchant, Nathan uhttp://doi.wiley.com/10.1002/rse2.7102589nas a2200253 4500008004100000022001400041245009400055210006900149260002000218300001600238490000800254520170300262653003501965653003602000653001902036653003302055653002002088100002502108700002102133700002202154700002202176700001702198856012002215 2013 eng d a0022-094900aThe simple ears of noctuoid moths are tuned to the calls of their sympatric bat community0 asimple ears of noctuoid moths are tuned to the calls of their sy cFeb-04-20132149 a3954 - 39620 v2163 a

nsects with bat-detecting ears are ideal animals for investigating sensory system adaptations to predator cues. Noctuid moths have two auditory receptors (A1 and A2) sensitive to the ultrasonic echolocation calls of insectivorous bats. Larger moths are detected at greater distances by bats than smaller moths. Larger moths also have lower A1 best thresholds, allowing them to detect bats at greater distances and possibly compensating for their increased conspicuousness. Interestingly, the sound frequency at the lowest threshold is lower in larger than in smaller moths, suggesting that the relationship between threshold and size might vary across frequencies used by different bat species. Here, we demonstrate that the relationships between threshold and size in moths were only significant at some frequencies, and these frequencies differed between three locations (UK, Canada and Denmark). The relationships were more likely to be significant at call frequencies used by proportionately more bat species in the moths' specific bat community, suggesting an association between the tuning of moth ears and the cues provided by sympatric predators. Additionally, we found that the best threshold and best frequency of the less sensitive A2 receptor are also related to size, and that these relationships hold when controlling for evolutionary relationships. The slopes of best threshold versus size differ, however, such that the difference in threshold between A1 and A2 is greater for larger than for smaller moths. The shorter time from A1 to A2 excitation in smaller than in larger moths could potentially compensate for shorter absolute detection distances in smaller moths.

10aallotonic frequency hypothesis10aconstant-frequency echolocation10ahorseshoe bats10apredator–prey interactions10asensory ecology1 aHofstede, H., M. ter1 aGoerlitz, H., R.1 aRatcliffe, J., M.1 aHolderied, M., W.1 aSurlykke, A. uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.093294https://syndication.highwire.org/content/doi/10.1242/jeb.09329403079nas a2200145 4500008004100000245011600041210006900157260001600226520256900242100002302811700001402834700001602848700002002864856004902884 2017 eng d00aPotential for coupling the monitoring of bush-crickets with established large-scale acoustic monitoring of bats0 aPotential for coupling the monitoring of bushcrickets with estab cJan-01-20173 a

Monitoring biodiversity over large spatial and temporal scales is crucial for assessing the impact of global changes and environmental mitigation measures. However, large-scale monitoring of invertebrates remains poorly developed despite the importance of these organisms in ecosystem functioning. Exciting possibilities applicable to professional and citizen science are offered by new recording techniques and methods of semi-automated species recognition based on sound detection.


Static broad-spectrum detectors deployed to record throughout whole nights have been recommended for standardised acoustic monitoring of bats, but they have the potential to also collect acoustic data for other species groups. Large-scale deployment of such systems is only viable when combined with robust automated species identification algorithms. Here we examine the potential of such a system for detecting, identifying and monitoring bush-crickets (Orthoptera of the family Tettigoniidae). We use incidental sound recordings generated by an extensive citizen science bat survey and recordings from intensive site surveys to test a semi-automated step-wise method with a classifier for assigning species identities. We assess species’ diel activity patterns to make recommendations for survey timing and interpretation of existing nocturnal data sets and consider the feasibility of determining site occupancy.

Of six species of bush-crickets, the species classifier achieved over 85% accuracy for three, speckled bush-cricket, dark bush-cricket and Roesel's bush-cricket. It should be possible to automatically scan recordings for these species with minimal manual validation. Further refinement of the classifier is required for the three remaining species, in particular for the acoustically similar short-winged conehead and long-winged conehead. Diel activity patterns are species specific and it may be necessary to adjust the hours over which the detectors record to increase detection of key species, but this must be weighed against the costs in terms of increased memory and battery use and equipment security during daytime.

We conclude that with logistical support and centralised semi-automated species identification it is now possible for the public to contribute to large-scale acoustic monitoring of Orthoptera while recording bats. Further innovation of sound classifier algorithms is needed and would be aided by improved reference sound libraries from multiple locations spanning species’ ranges.

1 aNewson, Stuart, E.1 aBas, Yves1 aMurray, Ash1 aGillings, Simon uhttp://doi.wiley.com/10.1111/2041-210X.12720