02062nas a2200205 4500008004100000022001400041245013900055210006900194260001600263300001400279490000800293520137200301653002401673653001201697653002101709653002101730653002101751100002901772856005501801 2018 eng d a0340-759400aEvolutionarily conserved coding properties favour the neuronal representation of heterospecific signals of a sympatric katydid species0 aEvolutionarily conserved coding properties favour the neuronal r cJan-10-2018 a859 - 8720 v2043 a

To function as a mechanism in premating isolation, the divergent and species-specific calling songs of acoustic insects must be reliably processed by the afferent auditory pathway of receivers. Here, we analysed the responses of interneurons in a katydid species that uses long-lasting acoustic trills and compared these with previously reported data for homologous interneurons of a sympatric species that uses short chirps as acoustic signals. Some interneurons of the trilling species respond exclusively to the heterospecific chirp due to selective, low-frequency tuning and “novelty detection”. These properties have been considered as evolutionary adaptations in the sensory system of the chirper, which allow it to detect signals effectively during the simultaneous calling of the sympatric sibling species. We propose that these two mechanisms, shared by the interneurons of both species, did not evolve in the chirper to guarantee its ability to detect the chirp under masking conditions. Instead we suggest that chirpers evolved an additional, 2-kHz component in their song and exploited pre-existing neuronal properties for detecting their song under masking noise. The failure of some interneurons to respond to the conspecific song in trillers does not prevent intraspecific communication, as other interneurons respond to the trill.

10aAuditory processing10ainsects10aSelective coding10asignal detection10asignal evolution1 aKostarakos, Konstantinos uhttp://link.springer.com/10.1007/s00359-018-1282-002689nas a2200193 4500008004100000022001300041245010200054210006900156260001600225520202600241653002702267653002502294653001302319653002102332653002502353100002802378700002302406856006602429 2017 eng d a0378595500aThe heterospecific calling song can improve conspecific signal detection in a bushcricket species0 aheterospecific calling song can improve conspecific signal detec cJan-09-20173 a

In forest clearings of the Malaysian rainforest, chirping and trilling Mecopoda species often live in sympatry. We investigated whether a phenomenon known as stochastic resonance (SR) improved the ability of individuals to detect a low-frequent signal component typical of chirps when members of the heterospecific trilling species were simultaneously active. This phenomenon may explain the fact that the chirping species upholds entrainment to the conspecific song in the presence of the trill. Therefore, we evaluated the response probability of an ascending auditory neuron (TN-1) in individuals of the chirping Mecopoda species to triple-pulsed 2, 8 and 20 kHz signals that were broadcast 1 dB below the hearing threshold while increasing the intensity of either white noise or a typical triller song.

Our results demonstrate the existence of SR over a rather broad range of signal-to-noise ratios (SNRs) of input signals when periodic 2 kHz and 20 kHz signals were presented at the same time as white noise. Using the chirp-specific 2 kHz signal as a stimulus, the maximum TN-1 response probability frequently exceeded the 50% threshold if the trill was broadcast simultaneously. Playback of an 8 kHz signal, a common frequency band component of the trill, yielded a similar result. Nevertheless, using the trill as a masker, the signal-related TN-1 spiking probability was rather variable. The variability on an individual level resulted from correlations between the phase relationship of the signal and syllables of the trill. For the first time, these results demonstrate the existence of SR in acoustically-communicating insects and suggest that the calling song of heterospecifics may facilitate the detection of a subthreshold signal component in certain situations. The results of the simulation of sound propagation in a computer model suggest a wide range of sender-receiver distances in which the triller can help to improve the detection of subthreshold signals in the chirping species.

10aacoustic communication10aauditory interneuron10aEnsifera10asignal detection10astochastic resonance1 aAbdelatti, Zainab, A.S.1 aHartbauer, Manfred uhttp://linkinghub.elsevier.com/retrieve/pii/S037859551730211302493nas a2200265 4500008004100000245009300041210006900134260001600203520166400219653002601883653001801909653001701927653002001944653002101964653003101985653002302016653003202039653002102071653001002092100002102102700002702123700001502150700001302165856004902178 2017 eng d00aAcoustic monitoring for conservation in tropical forests: examples from forest elephants0 aAcoustic monitoring for conservation in tropical forests example cJan-01-20173 a

1. The accelerating loss of biodiversity worldwide demands effective tools for monitoring animal populations and informing conservation action. In habitats where direct observation is difficult (rain forests, oceans), or for cryptic species (shy, nocturnal), passive acoustic monitoring (PAM) provides cost-effective, unbiased data collec- tion. PAM has broad applicability in terrestrial environments, particularly tropical rain forests.


2. Using examples from studies of forest elephants in Central African rainforest,we show how PAM can be used to investigate cryptic behaviour, mechanisms of communication, estimate population size, quantify threats, and assess the efficacy of conservation strategies. We discuss the methodologies, requirements, and challenges of obtaining these data using acoustics. Where applicable, we compare these methods to more traditional approaches.


3. While PAM methods and associated analysis are maturing rapidly, mechanisms are needed for processing the dense raw data efficiently with standard computer hardware, speeding development of detection algorithms, and harnessing communication networks to move data from the field to research facilities.


4. Passive acoustic monitoring is a viable and cost-effective tool for conservation and should be incorporated in monitoring schemes much more broadly. The capability to quickly assess changes in behaviour, population size, and landscape use, simultaneously over large geographical areas, makes this approach attractive for detecting human-induced impacts and for assessing the success of conservation strategies.

10aanthropogenic impacts10aanti-poaching10abioacoustics10acryptic species10adensity estimate10alaw enforcement monitoring10aLoxodonta cyclotis10apassive acoustic monitoring10asignal detection10aSMART1 aWrege, Peter, H.1 aRowland, Elizabeth, D.1 aKeen, Sara1 aShiu, Yu uhttp://doi.wiley.com/10.1111/2041-210X.12730