@article {57992, title = {Solutions to the Cocktail Party Problem in Insects: Selective Filters, Spatial Release from Masking and Gain Control in Tropical Crickets}, journal = {PLoS ONE}, volume = {6}, year = {2011}, month = {Jun-12-2011}, pages = {e28593}, abstract = {

Background

Insects often communicate by sound in mixed species choruses; like humans and many vertebrates in crowded social environments they thus have to solve cocktail-party-like problems in order to ensure successful communication with conspecifics. This is even more a problem in species-rich environments like tropical rainforests, where background noise levels of up to 60 dB SPL have been measured.

Principal Findings

Using neurophysiological methods we investigated the effect of natural background noise (masker) on signal detection thresholds in two tropical cricket species Paroecanthus podagrosus and Diatrypa sp., both in the laboratory and outdoors. We identified three \‘bottom-up\’ mechanisms which contribute to an excellent neuronal representation of conspecific signals despite the masking background. First, the sharply tuned frequency selectivity of the receiver reduces the amount of masking energy around the species-specific calling song frequency. Laboratory experiments yielded an average signal-to-noise ratio (SNR) of \−8 dB, when masker and signal were broadcast from the same side. Secondly, displacing the masker by 180\° from the signal improved SNRs by further 6 to 9 dB, a phenomenon known as spatial release from masking. Surprisingly, experiments carried out directly in the nocturnal rainforest yielded SNRs of about \−23 dB compared with those in the laboratory with the same masker, where SNRs reached only \−14.5 and \−16 dB in both species. Finally, a neuronal gain control mechanism enhances the contrast between the responses to signals and the masker, by inhibition of neuronal activity in interstimulus intervals.

Conclusions

Thus, conventional speaker playbacks in the lab apparently do not properly reconstruct the masking noise situation in a spatially realistic manner, since under real world conditions multiple sound sources are spatially distributed in space. Our results also indicate that without knowledge of the receiver properties and the spatial release mechanisms the detrimental effect of noise may be strongly overestimated.

}, doi = {10.1371/journal.pone.002859310.1371/journal.pone.0028593.g00110.1371/journal.pone.0028593.g00210.1371/journal.pone.0028593.g00310.1371/journal.pone.0028593.g00410.1371/journal.pone.0028593.g00510.1371/journal.pone.0028593.g006}, url = {https://dx.plos.org/10.1371/journal.pone.0028593}, author = {Arne K. D. Schmidt and Heiner R{\"o}mer} } @article {57654, title = {A review of the elusive bicolored iris Snouted Treefrogs (Anura: Hylidae: Scinax~uruguayus group)}, journal = {PLOS ONE}, volume = {14}, year = {2019}, month = {Jan-09-2021}, pages = {e0222131}, abstract = {

The genus Scinax currently includes more than 120 species, recovered in two major clades, the S. catharinae and the S. ruber clades. The latter comprises 75 species, most of which remain unassigned to any species groups, while 12 are included in the S. rostratus and S. uruguayus groups. In this paper we present a taxonomic review of the two species currently included in the S. uruguayus group, discussing some putative phenotypic synapomorphies of this group. Although S. pinima and S. uruguayus have been considered as distinct species, this has been based on scant evidence, and several authors doubted of their distinctiveness. Our study of available specimens of S. pinima and S. uruguayus corroborates that both are valid and diagnosable species based on phenotypic evidence. Furthermore, our results show that S. pinima previously known only from its type locality, has a much widespread distribution than previously thought (including the Brazilian states of Paran\á, Santa Catarina, and Rio Grande do Sul), which, added to the biological information presented here allows to suggest the removal of this species from the \“Data Deficient\” IUCN Red List category to \“Least Concern\”. Also, we describe a new species formerly reported as S. aff. pinima and S. uruguayus from NE Argentina and some localities from the Brazilian State of Rio Grande do Sul. All species are diagnosed and characterized using adult and larval morphology, osteology, vocalizations, cytogenetics, and natural history.

}, doi = {10.1371/journal.pone.0222131}, url = {http://dx.plos.org/10.1371/journal.pone.0222131}, author = {Baldo, Diego and Araujo-Vieira, Katyuscia and Dario E. Cardozo and Borteiro, Claudio and Leal, Fernando and Pereyra, Mart{\'\i}n O. and Kolenc, Francisco and Lyra, Mariana L. and Garcia, Paulo C. A. and C{\'e}lio F. B. Haddad and Faivovich, Juli{\'a}n}, editor = {Mirande, Juan Marcos} } @article {57366, title = {Sex differences in auditory brainstem response audiograms from vasopressin-deficient Brattleboro and wild-type Long-Evans rats}, journal = {PLOS ONE}, volume = {14}, year = {2019}, month = {Jun-08-2021}, pages = {e0222096}, abstract = {

Rats are highly social creatures that produce ultrasonic vocalizations (USVs) during social interactions. Brattleboro rats, a Long-Evans derived rat that lacks vasopressin (AVP) due to a mutation in the Avp gene, exhibit atypical social behavior, including fewer USVs with altered spectrotemporal characteristics during social interactions. It is unclear why Brattleboro rats produce atypical USVs, but one factor could be differences in auditory acuity between them and wild-type Long Evans rats with functional vasopressin. Previous studies have suggested a link between increased levels of AVP and auditory processing. Additionally, few studies have investigated sex differences in auditory perception by Long-Evans rats. Sex differences in auditory acuity have been found throughout the animal kingdom, but have not yet been demonstrated in rat audiograms. This study aimed to measure auditory brainstem response (ABR) derived audiograms for frequencies ranging from 1 to 64 kHz in male and female homozygous Brattleboro (Hom), heterozygous Brattleboro (Het), and wild-type (WT) Long-Evans rats to better understand the role of AVP and sex differences in auditory processing by these rats. We failed to detect significant differences between the ABR audiograms of Hom, Het, and WT Long-Evans rats, suggesting that varying levels of AVP do not affect auditory processing. Interestingly, males and females of all genotypes did differ in their ABR thresholds, with males exhibiting higher thresholds than females. The sex differences in auditory acuity were significant at the lowest and highest frequencies, possibly affecting the perception of USVs. These are the first known sex differences in rat audiograms.

}, doi = {10.1371/journal.pone.022209610.1371/journal.pone.0222096.g00110.1371/journal.pone.0222096.g00210.1371/journal.pone.0222096.t00110.1371/journal.pone.0222096.s001}, url = {http://dx.plos.org/10.1371/journal.pone.0222096}, author = {Charlton, Payton E. and Schatz, Kelcie C. and Burke, Kali and Paul, Matthew J. and Dent, Micheal L.}, editor = {Delano, Paul Hinckley} } @article {53579, title = {Deer browsing alters sound propagation in temperate deciduous forests}, journal = {PLOS ONE}, volume = {14}, year = {2019}, month = {Jan-02-2020}, pages = {e0211569}, abstract = {

The efficacy of animal signals is strongly influenced by the structure of the habitat in which they are propagating. In recent years, the habitat structure of temperate forests has been increasingly subject to modifications from foraging by white-tailed deer (Odocoileus virginianus). Increasing deer numbers and the accompanying browsing have been shown to alter vegetation structure and thus the foraging, roosting, and breeding habitats of many species. However, despite a large body of literature on the effects of vegetation structure on sound propagation, we do not yet know what impact deer browsing may have on acoustic communication. Here we used playback experiments to determine whether sound fidelity and amplitude of white noise, pure tones, and trills differed between deer-browsed and deer-excluded plots. We found that sound fidelity, but not amplitude, differed between habitats, with deer-browsed habitats having greater sound fidelity than deer-excluded habitats. Difference in sound propagation characteristics between the two habitats could alter the efficacy of acoustic communication through plasticity, cultural evolution or local adaptation, in turn influencing vocally-mediated behaviors (e.g. agonistic, parent-offspring, mate selection). Reduced signal degradation suggests vocalizations may retain more information, improving the transfer of information to both intended and unintended receivers. Overall, our results suggest that deer browsing impacts sound propagation in temperate deciduous forest, although much work remains to be done on the potential impacts on communication.

}, doi = {10.1371/journal.pone.0211569}, url = {http://dx.plos.org/10.1371/journal.pone.0211569}, author = {Boycott, Timothy J. and Gao, Jingyi and Gall, Megan D.} } @article {53544, title = {Subarctic singers: Humpback whale (Megaptera novaeangliae) song structure and progression from an Icelandic feeding ground during winter}, journal = {PLOS ONE}, volume = {14}, year = {2019}, month = {Nov-01-2020}, pages = {e0210057}, abstract = {

of traditional low latitude breeding grounds. Songs from a subarctic feeding ground during the winter were quantitatively characterized to investigate the structure and temporal changes of the songs at such an atypical location. Recordings were collected from 26. January to 12. March, 2011, using bottom mounted recorders. Humpback songs were detected on 91\% of the recording days with peak singing activities during 9.\–26. February. The majority of the recordings included multiple chorusing singers. The songs were characterized by a) common static themes which transitioned consistently to predictable themes, b) shifting themes which occurred less predictably and c) rare themes. A set median sequence was found for four different periods (sets) of recordings (approximately 1 week each). The set medians were highly similar and formed a single cluster indicating that the sequences of themes sung in this area belonged to a single cluster of songs despite of the variation caused by the shifting themes. These subarctic winter songs could, thus, represent a characteristic song type for this area which is comparable to extensively studied songs from traditional low latitude breeding grounds. An increase in the number of themes per sequence was observed throughout the recording period including minor changes in the application of themes in the songs; indicating a gradual song progression. The results confirm that continual singing of sophisticated songs occur during the breeding season in the subarctic. In addition to being a well-established summer feeding ground the study area appears to be an important overwintering site for humpback whales delaying or canceling their migration where males engage in active sexual displays, i.e. singing. Importantly, such singing activity on a shared feeding ground likely aids the cultural transmission of songs in the North Atlantic.

}, doi = {10.1371/journal.pone.0210057}, url = {http://dx.plos.org/10.1371/journal.pone.0210057}, author = {Magn{\'u}sd{\'o}ttir, Edda E. and Lim, Rangyn}, editor = {Jon T. Sakata} } @article {53537, title = {Song variation of the South Eastern Indian Ocean pygmy blue whale population in the Perth Canyon, Western Australia}, journal = {PLOS ONE}, volume = {14}, year = {2019}, month = {Oct-01-2020}, pages = {e0208619}, abstract = {

Sea noise collected over 2003 to 2017 from the Perth Canyon, Western Australia was analysed for variation in the South Eastern Indian Ocean pygmy blue whale song structure. The primary song-types were: P3, a three unit phrase (I, II and III) repeated with an inter-song interval (ISI) of 170\–194 s; P2, a phrase consisting of only units II \& III repeated every 84\–96 s; and P1 with a phrase consisting of only unit II repeated every 45\–49 s. The different ISI values were approximate multiples of each other within a season. When comparing data from each season, across seasons, the ISI value for each song increased significantly through time (all fits had p \<\< 0.001), at 0.30 s/Year (95\%CI 0.217\–0.383), 0.8 s/Year (95\%CI 0.655\–1.025) and 1.73 s/Year (95\%CI 1.264\–2.196) for the P1, P2 and P3 songs respectively. The proportions of each song-type averaged at 21.5, 24.2 and 56\% for P1, P2 and P3 occurrence respectively and these ratios could vary by up to \± 8\% (95\% CI) amongst years. On some occasions animals changed the P3 ISI to be significantly shorter (120\–160 s) or longer (220\–280 s). Hybrid song patterns occurred where animals combined multiple phrase types into a repeated song. In recent years whales introduced further complexity by splitting song units. This variability of song-type and proportions implies abundance measure for this whale sub population based on song detection needs to factor in trends in song variability to make data comparable between seasons. Further, such variability in song production by a sub population of pygmy blue whales raises questions as to the stability of the song types that are used to delineate populations. The high level of song variability may be driven by an increasing number of background whale callers creating \‘noise\’ and so forcing animals to alter song in order to \‘stand out\’ amongst the crowd.

}, doi = {10.1371/journal.pone.0208619}, url = {http://dx.plos.org/10.1371/journal.pone.0208619}, author = {Jolliffe, Capri D. and McCauley, Robert D. and Gavrilov, Alexander N. and Jenner, K. Curt S. and Jenner, Micheline-Nicole M. and Duncan, Alec J.}, editor = {Matsumoto, Haru} } @article {53504, title = {Automatic detection, classification, and quantification of sciaenid fish calls in an estuarine soundscape in the Southeast United States}, journal = {PLOS ONE}, volume = {14}, year = {2019}, month = {Apr-01-2020}, pages = {e0209914}, abstract = {

In the Southeast USA, major contributors to estuarine soundscapes are the courtship calls produced by fish species belonging to the family Sciaenidae. Long-term monitoring of sciaenid courtship sounds may be valuable in understanding reproductive phenology, but this approach produces massive acoustic datasets. With this in mind, we designed a feature-based, signal detector for sciaenid fish calls and tested the efficacy of this detector against manually reviewed data. Acoustic recorders were deployed to collect sound samples for 2 min every 20 min at four stations in the May River estuary, South Carolina, USA from February to November, 2014. Manual analysis of acoustic files revealed that four fish species, belonging to the family Sciaenidae, were the major sound producers in this estuarine soundscape, and included black drum (Pogonias cromis), silver perch (Bairdiella chrysoura), spotted seatrout (Cynoscion nebulosus), and red drum (Sciaenops ocellatus). Recorded calls served as an acoustic library of signature features that were used to create a signal detector to automatically detect, classify, and quantify the number of calls in each acoustic file. Correlation between manual and automatic detection was significant and precision varied from 61\% to 100\%. Automatic detection provided quantitative data on calling rates for this long-term data set. Positive temperature anomalies increased calling rates of black drum, silver perch, and spotted seatrout, while negative anomalies increased calling rates of red drum. Acoustic monitoring combined with automatic detection could be an additional or alternative method for monitoring sciaenid spawning and changes in phenology associated with climate change.

}, doi = {10.1371/journal.pone.0209914}, url = {http://dx.plos.org/10.1371/journal.pone.0209914}, author = {Monczak, Agnieszka and Ji, Yiming and Soueidan, Jamileh and Montie, Eric W.} } @article {53233, title = {Four types of vibration behaviors in a mole cricket}, journal = {PLOS ONE}, volume = {13}, year = {2018}, month = {Oct-10-2018}, pages = {e0204628}, abstract = {

Vibrational communication is known in some subterranean insects. Except for their use in sexual signaling, vibration behavior has rarely been reported. We report here four distinct types of substrate-based vibration behaviors in the mole cricket, Gryllotalpa orientalis, which are not associated with sexual signaling because of the occurrence of these behaviors in nymphs: (1) scraping with the forelegs; (2) foreleg taps (tapping with the forelegs); (3) palpal taps (tapping with the maxillary palpi); and (4) tremulation (back-and-forth movement of the whole body). Scraping is hypothesized to be used for the inspection of borrows. Foreleg taps are possibly informing nearby individuals of their presence, because it is never observed in solitary conditions. Palpal taps are rarely observed and its function is unknown. Tremulation is possibly related to avoidance of conspecific individual approaching and touching. The combination of the four vibration behaviors in the mole cricket may be unique among insects.

}, doi = {10.1371/journal.pone.0204628}, url = {http://dx.plos.org/10.1371/journal.pone.0204628}, author = {Hayashi, Yaoko and Yoshimura, Jin and Roff, Derek A. and Kumita, Tetsuro and Shimizu, Akira}, editor = {Tony Robillard} } @article {53066, title = {Call and be counted! Can we reliably estimate the number of callers in the indri{\textquoteright}s (Indri indri) song?}, journal = {PLOS ONE}, volume = {13}, year = {2018}, month = {Mar-08-2018}, pages = {e0201664}, abstract = {

Estimating the number of animals participating in a choral display may contribute reliable information on animal population estimates, particularly when environmental or behavioral factors restrict the possibility of visual surveys. Difficulties in providing a reliable estimate of the number of singers in a chorus are many (e.g., background noise masking, overlap). In this work, we contributed data on the vocal chorusing of the indri lemurs (Indri indri), which emit howling cries, known as songs, uttered by two to five individuals. We examined whether we could estimate the number of emitters in a chorus by screening the fundamental frequency in the spectrograms and the total duration of the songs, and the reliability of those methods when compared to the real chorus size. The spectrographic investigation appears to provide reliable information on the number of animals participating in the chorusing only when this number is limited to two or three singers. We also found that the Acoustic Complexity Index positively correlated with the real chorus size, showing that an automated analysis of the chorus may provide information about the number of singers. We can state that song duration shows a correlation with the number of emitters but also shows a remarkable variation that remains unexplained. The accuracy of the estimates can reflect the high variability in chorus size, which could be affected by group composition, season and context. In future research, a greater focus on analyzing frequency change occurring during these collective vocal displays should improve our ability to detect individuals and allow a finer tuning of the acoustic methods that may serve for monitoring chorusing mammals.

}, doi = {10.1371/journal.pone.0201664}, url = {http://dx.plos.org/10.1371/journal.pone.0201664}, author = {Torti, Valeria and Valente, Daria and De Gregorio, Chiara and Comazzi, Carlo and Miaretsoa, Longondraza and Ratsimbazafy, Jonah and Giacoma, Cristina and Gamba, Marco}, editor = {Reby, David} } @article {52748, title = {Revealing the ecological content of long-duration audio-recordings of the environment through clustering and visualisation}, journal = {PLOS ONE}, volume = {13}, year = {2018}, month = {Jan-03-2018}, pages = {e0193345}, abstract = {

Audio recordings of the environment are an increasingly important technique to monitor biodiversity and ecosystem function. While the acquisition of long-duration recordings is becoming easier and cheaper, the analysis and interpretation of that audio remains a significant research area. The issue addressed in this paper is the automated reduction of environmental audio data to facilitate ecological investigations. We describe a method that first reduces environmental audio to vectors of acoustic indices, which are then clustered. This can reduce the audio data by six to eight orders of magnitude yet retain useful ecological information. We describe techniques to visualise sequences of cluster occurrence (using for example, diel plots, rose plots) that assist interpretation of environmental audio. Colour coding acoustic clusters allows months and years of audio data to be visualised in a single image. These techniques are useful in identifying and indexing the contents of long-duration audio recordings. They could also play an important role in monitoring long-term changes in species abundance brought about by habitat degradation and/or restoration.

}, doi = {10.1371/journal.pone.0193345}, url = {http://dx.plos.org/10.1371/journal.pone.0193345}, author = {Yvonne F. Phillips and Paul Roe} } @article {52595, title = {Sound-mapping a coniferous forest{\textemdash}Perspectives for biodiversity monitoring and noise mitigation}, journal = {PLOS ONE}, volume = {13}, year = {2018}, month = {Oct-01-2018}, pages = {e0189843}, abstract = {

Acoustic diversity indices have been proposed as low-cost biodiversity monitoring tools. The acoustic diversity of a soundscape can be indicative of the richness of an acoustic community and the structural/vegetation characteristics of a habitat. There is a need to apply these methods to landscapes that are ecologically and/or economically important. We investigate the relationship between the acoustic properties of a coniferous forest with stand-age and structure. We sampled a 73 point grid in part of the UK\’s largest man-made lowland coniferous plantation forest, covering a 320ha mosaic of different aged stands. Forest stands ranged from 0\–85 years old providing an age-gradient. Short soundscape recordings were collected from each grid point on multiple mornings (between 6am-11am) to capture the dawn chorus. We repeated the study during July/August in 2014 and again in 2015. Five acoustic indices were calculated for a total of 889 two minute samples. Moderate relationships between acoustic diversity with forest stand-age and vegetation characteristics (canopy height; canopy cover) were observed. Ordinations suggest that as structural complexity and forest age increases, the higher frequency bands (4-10KHz) become more represented in the soundscape. A strong linear relationship was observed between distance to the near- est road and the ratio of anthropogenic noise to biological sounds within the soundscape. Similar acoustic patterns were observed in both years, though acoustic diversity was generally lower in 2014, which was likely due to differences in wind conditions between years. Our results suggest that developing these relatively low-cost acoustic monitoring methods to inform adaptive management of production landscapes, may lead to improved biodiversity monitoring. The methods may also prove useful for modelling road noise, landscape planning and noise mitigation.

}, doi = {10.1371/journal.pone.0189843}, url = {http://dx.plos.org/10.1371/journal.pone.0189843}, author = {Turner, Anthony and Fischer, Michael and Tzanopoulos, Joseph}, editor = {Farina, Almo} } @article {51468, title = {Vocalizations of adult male Asian koels (Eudynamys scolopacea) in the breeding season}, journal = {PLOS ONE}, volume = {12}, year = {2017}, pages = {e0186604}, abstract = {

Defining the vocal repertoire provides a basis for understanding the role of acoustic signals in sexual and social interactions of an animal. The Asian koel (Eudynamys scolopacea) is a migratory bird which spends its summer breeding season in the plains of Pakistan. The bird is typically wary and secretive but produces loud and distinct calls, making it easily detected when unseen. Like the other birds in the wild, presumably Asian koels use their calls for social cohesion and coordination of different behaviors. To date, the description of vocal repertoire of the male Asian koel has been lacking. Presently we analyzed and described for the first time the vocalizations of the adult male Asian koel, recorded in two consecutive breeding seasons. Using 10 call parameters, we categorized the vocalization type into six different categories on the basis of spectrogram and statistical analyses, namely the; \“type 1 cooee call\”, \“type 2 cooee call\”, \“type 1 coegh call\”, \“type 2 coegh call\”, \“wurroo call\” and \“coe call\”. These names were assigned not on the basis of functional analysis and were therefore onomatopoeic. Stepwise cross validated discriminant function analysis classified the vocalization correctly (100\%) into the predicted vocal categories that we initially classified on the basis of spectrographic examination. Our findings enrich the biological knowledge about vocalizations of the adult male Asian koel and provide a foundation for future acoustic monitoring of the species, as well as for comparative studies with vocalizations of other bird species of the cuckoo family. Further studies on the vocalizations of the Asian koel are required to unravel their functions in sexual selection and individual recognition.

}, doi = {10.1371/journal.pone.0186604}, url = {http://dx.plos.org/10.1371/journal.pone.0186604}, author = {Khan, Abdul Aziz and Qureshi, Irfan Zia}, editor = {Mosk{\'a}t, Csaba} } @article {47919, title = {Flight of the bumble bee: Buzzes predict pollination services}, journal = {PLOS ONE}, volume = {12}, year = {2017}, month = {Jul-06-2017}, pages = {e0179273}, abstract = {

Multiple interacting factors drive recent declines in wild and managed bees, threatening their pollination services. Widespread and intensive monitoring could lead to more effective management of wild and managed bees. However, tracking their dynamic populations is costly. We tested the effectiveness of an inexpensive, noninvasive and passive acoustic survey technique for monitoring bumble bee behavior and pollination services. First, we assessed the relationship between the first harmonic of the flight buzz (characteristic frequency) and pollinator functional traits that influence pollination success using flight cage experiments and a literature search. We analyzed passive acoustic survey data from three locations on Pennsylvania Mountain, Colorado to estimate bumble bee activity. We developed an algorithm based on Computational Auditory Scene Analysis that identified and quantified the number of buzzes recorded in each location. We then compared visual and acoustic estimates of bumble bee activity. Using pollinator exclusion experiments, we tested the power of buzz density to predict pollination services at the landscape scale for two bumble bee pollinated alpine forbs (Trifolium dasyphyllum and T. parryi). We found that the characteristic frequency was correlated with traits known to affect pollination efficacy, explaining 30\–52\% of variation in body size and tongue length. Buzz density was highly correlated with visual estimates of bumble bee density (r = 0.97), indicating that acoustic signals are predictive of bumble bee activity. Buzz density predicted seed set in two alpine forbs when bumble bees were permitted access to the flowers, but not when they were excluded from visiting. Our results indicate that acoustic signatures of flight can be deciphered to monitor bee activity and pollination services to bumble bee pollinated plants. We propose that applications of this technique could assist scientists and farmers in rapidly detecting and responding to bee population declines.

}, doi = {10.1371/journal.pone.0179273}, url = {http://dx.plos.org/10.1371/journal.pone.0179273}, author = {Miller-Struttmann, Nicole E. and Heise, David and Schul, Johannes and Geib, Jennifer C. and Galen, Candace}, editor = {Borges, Renee M.} } @article {47912, title = {Female Field Crickets Incur Increased Parasitism Risk When Near Preferred Song}, journal = {PLoS ONE}, volume = {5}, year = {2010}, month = {Sep-03-2010}, pages = {e9592}, abstract = {

Female animals often prefer males with conspicuous traits because these males provide direct or indirect benefits. Conspicuous male traits, however, can attract predators. This not only increases the risk of predation for conspicuous males but also for the females that prefer them. In the variable field cricket, Gryllus lineaticeps, males that produce preferred song types provide females with greater material benefits, but they are also more likely to attract lethal parasitoid flies. First, we conducted a field experiment that tested the hypothesis that females have a greater risk of fly parasitism when in association with preferred high chirp rate males. Females were nearly twice as likely to be parasitized when caged with high chirp rate song than when caged with low chirp rate song. Females may thus be forced to trade off the quality of the benefits they receive from mating with preferred males and the risk of being killed by a predator when near these males. Second, we assessed female parasitism rates in a natural population. Up to 6\% of the females were parasitized in field samples. Because the females we collected could have become parasitized had they not been collected, this provides a minimum estimate of the female parasitism rate in the field. In a laboratory study, we found no difference in the proportion of time parasitized and unparasitized females spent hiding under shelters; thus, differences in activity patterns do not appear to have biased our estimate of female parasitism rates. Overall, our results suggest that female association costs have the potential to shape the evolution of female mating preferences.

}, doi = {10.1371/journal.pone.000959210.1371/journal.pone.0009592.g00110.1371/journal.pone.0009592.g002}, url = {http://dx.plos.org/10.1371/journal.pone.0009592}, author = {Martin, Cassandra M. and William E. Wagner} } @article {47910, title = {Male Responses to Conspecific Advertisement Signals in the Field Cricket Gryllus rubens (Orthoptera: Gryllidae)}, journal = {PLoS ONE}, volume = {6}, year = {2011}, month = {Aug-01-2012}, pages = {e16063}, abstract = {

In many species males aggregate and produce long-range advertisement signals to attract conspecific females. The majority of the receivers of these signals are probably other males most of the time, and male responses to competitors\’ signals can structure the spatial and temporal organization of the breeding aggregation and affect male mating tactics. I quantified male responses to a conspecific advertisement stimulus repeatedly over three age classes in Gryllus rubens (Orthoptera: Gryllidae) in order to estimate the type and frequency of male responses to the broadcast stimulus and to determine the factors affecting them. Factors tested included body size, wing dimorphism, age, and intensity of the broadcast stimulus. Overall, males employed acoustic response more often than positive phonotactic response. As males aged, the frequency of positive phonotactic response decreased but that of the acoustic response increased. That is, males may use positive phonotaxis in the early stages of their adult lives, possibly to find suitable calling sites or parasitize calling males, and then later in life switch to acoustic responses in response to conspecific advertisement signals. Males with smaller body size more frequently exhibited acoustic responses. This study suggests that individual variation, more than any factors measured, is critical for age-dependent male responses to conspecific advertisement signals.

}, doi = {10.1371/journal.pone.001606310.1371/journal.pone.0016063.g00110.1371/journal.pone.0016063.g00210.1371/journal.pone.0016063.t00110.1371/journal.pone.0016063.t00210.1371/journal.pone.0016063.t00310.1371/journal.pone.0016063.t004}, url = {http://dx.plos.org/10.1371/journal.pone.0016063}, author = {Jang, Yikweon} } @article {17269, title = {Can treefrog phylogeographical clades and species{\textquoteright} phylogenetic topologies be recovered by bioacoustical analyses?}, journal = {PLOS ONE}, volume = {12}, year = {2017}, month = {Dec-02-2018}, pages = {e0169911}, abstract = {

Phenotypic traits, such as the frog advertisement call, are generally correlated with interspecific genetic variation, and, as a consequence of strong sexual selection, these behaviors may carry a phylogenetic signal. However, variation in acoustic traits is not always correlated with genetic differences between populations (intraspecific variation); phenotypic plasticity and environmental variables may explain part of such variation. For example, local processes can affect acoustic properties in different lineages due to differences in physical structure, climatic conditions, and biotic interactions, particularly when populations are isolated. However, acoustic traits can be used to test phylogenetic hypotheses. We analyzed the advertisement calls of Dendropsophus elegans males from 18 sites and compared them with those of four closely related congeneric species, in order to test for differences between inter and intraspecific variation. We analyzed 451 calls of 45 males of these five species. Because males from distant sites were grouped together without population congruence, differences found in advertisement calls among individuals were not correlated with phylogeographical clades. Phylogenetic and cluster analyses of the D. elegans clades and those of closely related species grouped all five species into the same topology, as reported by previous molecular and morphological phylogenies. However, the topology of the D. elegans phylogeographical clades did not match the topology previously reported. Acoustic communication in D. elegans seems to be conserved among populations, and the phylogeographical history of the species does not explain the variation among lineages in call properties, despite some congruent phylogenetic signals evident at the species level. Based on molecular clocks retrieved from the literature, it seems that more than 6.5 million years of divergence (late Miocene) are necessary to allow significant changes to occur in the acoustic properties of these treefrog calls, making it possible to recover their phylogenetic history only based on acoustic evidence.

}, doi = {10.1371/journal.pone.0169911}, url = {http://dx.plos.org/10.1371/journal.pone.0169911}, author = {Forti, Lucas Rodriguez and Lingnau, Rodrigo and Encarna{\c c}{\~a}o, Lais Carvalho and Bertoluci, Jaime and Lu{\'\i}s Felipe Toledo}, editor = {Chiang, Tzen-Yuh} } @article {15578, title = {Automated Sound Recognition Provides Insights into the Behavioral Ecology of a Tropical Bird}, journal = {PLOS ONE}, volume = {12}, year = {2017}, month = {Jan-01-2018}, pages = {e0169041}, doi = {10.1371/journal.pone.016904110.1371}, url = {http://dx.plos.org/10.1371/journal.pone.0169041}, author = {Olaf Jahn and Ganchev, Todor D. and Marques, Marinez I. and Schuchmann, Karl-L.}, editor = {Michael L. Fine} } @article {12664, title = {Shrinking Wings for Ultrasonic Pitch Production: Hyperintense Ultra-Short-Wavelength Calls in a New Genus of Neotropical Katydids (Orthoptera: Tettigoniidae)}, journal = {PLoS ONE}, volume = {9}, year = {2014}, month = {May-06-2014}, pages = {e98708}, abstract = {

This article reports the discovery of a new genus and three species of predaceous katydid (Insecta: Orthoptera) from Colombia and Ecuador in which males produce the highest frequency ultrasonic calling songs so far recorded from an arthropod. Male katydids sing by rubbing their wings together to attract distant females. Their song frequencies usually range from audio (5 kHz) to low ultrasonic (30 kHz). However, males of Supersonus spp. call females at 115 kHz, 125 kHz, and 150 kHz. Exceeding the human hearing range (50 Hz\–20 kHz) by an order of magnitude, these insects also emit their ultrasound at unusually elevated sound pressure levels (SPL). In all three species these calls exceed 110 dB SPL rms re 20 m Pa (at 15 cm). Males of Supersonus spp. have unusually reduced forewings (,0.5 mm 2 ). Only the right wing radiates appreciable sound, the left bears the file and does not show a particular resonance. In contrast to most katydids, males of Supersonus spp. position and move their wings during sound production so that the concave aspect of the right wing, underlain by the insect dorsum, forms a contained cavity with sharp resonance. The observed high SPL at extreme carrier frequencies can be explained by wing anatomy, a resonant cavity with a membrane, and cuticle deformation.

}, doi = {10.1371/journal.pone.0098708}, url = {http://dx.plos.org/10.1371/journal.pone.0098708}, author = {Sarria-S, Fabio A. and Glenn K. Morris and James F.C. Windmill and Joseph Curt Jackson and Fernando Montealegre-Zapata}, editor = {Etges, William J.} } @article {11903, title = {Characterization and Generation of Male Courtship Song in Cotesia congregata (Hymenoptera: Braconidae)}, journal = {PLoS ONE}, volume = {8}, year = {2013}, month = {Oct-04-2014}, pages = {e62051}, abstract = {

Male parasitic wasps attract females with a courtship song produced by rapid wing fanning. Songs have been described for several parasitic wasp species; however, beyond association with wing fanning, the mechanism of sound generation has not been examined. We characterized the male courtship song of Cotesia congregata (Hymenoptera: Braconidae) and investigated the biomechanics of sound production. Courtship songs were recorded using high-speed videography (2,000 fps) and audio recordings. The song consists of a long duration amplitude-modulated \“buzz\” followed by a series of pulsatile higher amplitude \“boings,\” each decaying into a terminal buzz followed by a short inter-boing pause while wings are stationary. Boings have higher amplitude and lower frequency than buzz components. The lower frequency of the boing sound is due to greater wing displacement. The power spectrum is a harmonic series dominated by wing repetition rate ~220 Hz, but the sound waveform indicates a higher frequency resonance ~5 kHz. Sound is not generated by the wings contacting each other, the substrate, or the abdomen. The abdomen is elevated during the first several wing cycles of the boing, but its position is unrelated to sound amplitude. Unlike most sounds generated by volume velocity, the boing is generated at the termination of the wing down stroke when displacement is maximal and wing velocity is zero. Calculation indicates a low Reynolds number of ~1000. Acoustic pressure is proportional to velocity for typical sound sources. Our finding that the boing sound was generated at maximal wing displacement coincident with cessation of wing motion indicates that it is caused by acceleration of the wing tips, consistent with a dipole source. The low Reynolds number requires a high wing flap rate for flight and predisposes wings of small insects for sound production.

}, doi = {10.1371/journal.pone.0062051}, author = {Bredlau, Justin P. and Mohajer, Yasha J. and Cameron, Timothy M. and Kester, Karen M.}, editor = {Zeil, Jochen} }