@article {58458, title = {Temporal Shifts in Conspicuousness: Mate Attraction Displays of the Texas Field Cricket, Gryllus texensis}, journal = {Ethology}, volume = {110}, year = {2004}, pages = {963-975}, chapter = {963}, abstract = {

Conspicuous mate attraction displays can simultaneously draw the attention of potential mates and predators, placing the signaller in peril of becoming prey. The balance between these countervailing forms of selection has the potential to shape mate attraction displays. Male Texas field crickets (Gryllus texensis; Orthoptera) signal acoustically to attract mates. Mating signals also attract acoustically orienting parasitoid flies (Ormia ochracea; Tachinidae). Both the abundance of female crickets and parasitoid flies fluctuates throughout the night. We show mate attraction displays exhibit diel shifts that correlate positively with expected female cricket presence and negatively with expected parasitoid fly activity. During early evening, when parasitoids are most common and mating is scarce, crickets signal less often and with reduced conspicuousness. During the second half of the evening, when sexually receptive females are abundant and parasitoids are scarce, crickets signal more often and with enhanced conspicuousness. These diel shifts in mate attraction displays do not appear to result from male crickets detecting parasitoid flies or female crickets and altering their behaviour accordingly. Males in close proximity to parasitoid flies or female crickets do not signal differently than lone males. Instead, diel pattern shifts in mate attraction displays appear to be a selective response to trade-offs between natural selection via parasitism and sexual selection via mate choice.

}, author = {Susan M. Bertram and S. Xochitl Orozco and Rudy Bellani} } @article {53369, title = {Soft songs in male ortolan buntings are used in an aggressive context but are not an aggressive signal}, journal = {Ethology}, volume = {124}, year = {2018}, month = {Jan-08-2018}, pages = {549 - 558}, abstract = {

Many bird species produce low-amplitude acoustic signals that have been poorly studied in comparison with loud, broadcast songs used for mate attraction and repelling rivals. In some birds, these soft signals were found to be emitted in an antagonistic context and were the most reliable predictor of a subsequent physical attack. The function of this signal is poorly understood, and several hypotheses have been proposed to explain the mechanisms and possible functions of such low-amplitude signals. The subject of this study is the ortolan bunting, a small passerine species that produces soft songs during territorial defence. In this study, we aim to study whether the soft songs of the ortolan bunting are a signal of increased aggressiveness by testing if they meet the context, prediction and response criteria of aggressive signals. We simulated stranger male intrusion into a focal male territory with three different playback experiments. We found no significant differences in the male responses to the taxidermic model regardless of whether they were or were not producing soft songs in response. The males responded more strongly to loud songs than to soft songs during the simulated intrusions, and the males did not treat soft songs as a predictor of conflict escalation. Although soft songs clearly appeared during territorial encounters and were not present during spontaneous singing before the intrusions, our results did not support the hypothesis that soft songs indicate aggressive character. We suggest that soft songs in the ortolan bunting are intentionally used by birds to modify their intentions or target-specific individuals within a close range.

}, keywords = {Aggressive signals, ortolan bunting, soft song, territorial defence}, doi = {10.1111/eth.2018.124.issue-810.1111/eth.12758}, url = {http://doi.wiley.com/10.1111/eth.2018.124.issue-8}, author = {Jakubowska, Aleksandra and Osiejuk, Tomasz S.}, editor = {Fusani, L.} } @article {53368, title = {Ravens adjust their antipredatory responses to con- and hetero-specific alarms to the perceived threat}, journal = {Ethology}, volume = {124}, year = {2018}, month = {Jan-08-2018}, pages = {609 - 616}, abstract = {

Heterospecific alarm calls are typically found in situations where multiple species have a common predator. In birds, they are particularly common in mixed mixed-species flocks. In species with highly developed social and cognitive abilities like corvids, there is the potential for differential responses to heterospecific vs. conspecific calls according to the riskiness of the habitat. We tested the responses of free-ranging ravens (Corvus corax) to conspecific alarm calls and compared them to heterospecific alarm calls of jackdaws (Corvus monedula). We observed the proportion of ravens leaving the feeding site after the con- or hetero-specific playback was presented in a situation of low threat (wild boar\—Sus scrofa enclosure) and high threat of predation (wolf\—Canis lupus enclosure). We show that ravens responded to conspecific calls more intensively at the wolves than at the wild boar, but the response to conspecific calls was in both enclosures stronger than to the control (great tit\—Parus major song). The response to the heterospecific alarm was also stronger in the wolves\’ enclosure, but it did not differ from control in the wild boar enclosure. These findings suggest that ravens are aware of the meaning of the jackdaw alarm calls, but they respond to it only in a situation of high predatory threat (wolves are present). In the wild boar enclosure, the ravens probably consider jackdaws warning against some other predator, very probably harmless to ravens. This interpretation requires further testing, as both enclosures differ also in respect to other parameters like food quality and shelter availability.

}, keywords = {avoidance, corvid, honest signal, jackdaw, predator, threat}, doi = {10.1111/eth.2018.124.issue-810.1111/eth.12764}, url = {http://doi.wiley.com/10.1111/eth.2018.124.issue-8}, author = {N{\'a}carov{\'a}, Jana and Vesel{\'y}, Petr and Bugnyar, Thomas}, editor = {Tregenza, T.} } @article {53367, title = {Limited flexibility in female Pacific field cricket ( Teleogryllus oceanicus) exploratory behaviors in response to perceived social environment}, journal = {Ethology}, volume = {124}, year = {2018}, month = {Jan-09-2018}, pages = {650 - 656}, abstract = {

How populations adapt, or not, to rapid evolution of sexual signals has important implications for population viability, but is difficult to assess due to the paucity of examples of sexual signals evolving in real time. In Hawaiian populations of the Pacific field cricket (Teleogryllus oceanicus), selection from a deadly parasitoid fly has driven the rapid loss of a male acoustic signal, calling song, that females use to locate and evaluate potential mates. In this newly quiet environment where many males are obligately silent, how do phonotactic females find mates? Previous work has shown that the acoustic rearing environment (presence or absence of male calling song) during late juvenile stages and early adulthood exposes adaptive flexibility in locomotor behaviors of males, as well as mating behaviors in both sexes that helps facilitate the spread of silent (flatwing) males. Here, we tested whether females also show acoustically induced plasticity in walking behaviors using laboratory-reared populations of T. oceanicus from Kauai (HI; \>90\% flatwings), Oahu (HI; ~50\% flatwings), and Mangaia (Cook Islands; no flatwings or parasitoid fly). Though we predicted that females reared without song exposure would increase walking behaviors to facilitate mate localization when song is rare, we discovered that, unlike males, female T. oceanicus showed relatively little plasticity in exploratory behaviors in response to an acoustic rearing environment. Across all three populations, exposure to male calling song during development did not affect latency to begin walking, distance walked, or general activity of female crickets. However, females reared in the absence of song walked slower and showed a marginally non-significant tendency to walk for longer durations of time in a novel environment than those reared in the presence of song. Overall, plasticity in female walking behaviors appears unlikely to have facilitated sexual signal loss in this species.

}, doi = {10.1111/eth.2018.124.issue-910.1111/eth.12767}, url = {http://doi.wiley.com/10.1111/eth.2018.124.issue-9}, author = {Heinen-Kay, Justa L. and Strub, Daina B. and Zuk, Marlene} } @article {53366, title = {Tree cricket baffles are manufactured tools}, journal = {Ethology}, volume = {124}, year = {2018}, month = {Jan-09-2018}, pages = {691 - 693}, abstract = {

Tree crickets use sound to attract mates and make acoustic baffles to increase their sound production efficiency. It has been recently discovered that these insects use a flexible yet inherited behavioural programme to make acoustically optimal baffles. Whether these baffles qualify as tools, however, remains controversial. Here, baffle-using and baffle-making behaviours are analysed using the most current and authoritative definition of tool use. The current definition of tool use does not require the tool to be detached from the substrate and includes attached but manipulable external objects. Given this schema, tree cricket baffles, which are attached but manipulated prior to use, must be considered tools. The mode of manufacture for a baffle is \“Subtract,\” and the mode of use is \“Drape\”.

}, doi = {10.1111/eth.2018.124.issue-910.1111/eth.12773}, url = {http://doi.wiley.com/10.1111/eth.2018.124.issue-9}, author = {Mhatre, Natasha}, editor = {Bertram, S.} } @article {53364, title = {Quiet violence: Savannah Sparrows respond to playback-simulated rivals using low-amplitude songs as aggressive signals}, journal = {Ethology}, volume = {124}, year = {2018}, month = {Jan-10-2018}, pages = {724 - 732}, abstract = {

When animals compete over resources such as breeding territories, they often use signals to communicate their aggressive intentions. By studying which signals are associated with aggressive interactions, we gain a deeper appreciation of animal behaviour. We studied aggressive signalling in male Savannah Sparrows, Passerculus sandwichensis, focusing on signals that precede physical attack against territorial intruders. We simulated intruders using song playback and taxidermic models, and we determined which behaviours were associated with physical attack. Previous studies that have used this approach suggest that many species produce songs of dramatically lower amplitude, or \“soft songs,\” as signals of aggressive intention. Savannah Sparrows, however, are not known to produce soft songs, and therefore, they provided an interesting system for testing signals that predict attack. Of 93 playback subjects, 23 males attacked the simulated intruder and 70 did not. To our surprise, Savannah Sparrows produced soft songs, and the number of soft songs was a significant predictor of attack on the simulated intruder. Birds also showed a nonsignificant tendency to produce more \“chip\” calls prior to attack on the simulated intruder, whereas three other measured behaviours (aggressive calls, wing waving and passes over the model) did not predict attack. Our study contributes to the growing body of research on aggressive territorial signals and reveals that soft song is an even more widespread signal of aggression in songbirds than previously recognized.

}, keywords = {aggressive signalling, animal communication, low-amplitude vocalizations, Savannah Sparrows, soft songs}, doi = {10.1111/eth.2018.124.issue-1010.1111/eth.12805}, url = {http://doi.wiley.com/10.1111/eth.2018.124.issue-10}, author = {Moran, Ines G. and Doucet, St{\'e}phanie M. and Newman, Amy E. M. and Ryan Norris, D. and Mennill, Daniel J.}, editor = {Koenig, W.} } @article {53363, title = {Advertising individual identity by mother and adolescent contact calls in Siberian wapiti Cervus elaphus sibiricus}, journal = {Ethology}, volume = {124}, year = {2018}, month = {Jan-10-2018}, pages = {733 - 742}, abstract = {

Individualistic contact calls facilitate mother-offspring reunion after separation. However, in many mammals, both the acoustic structure and individuality of contact calls differ between mother and young. In contrast, in Siberian wapiti Cervus elaphus sibiricus, contact calls are similar in the acoustics between mother and young, whereas effects of this similarity on vocal individuality were not investigated. In this study, we analyzed acoustic differences between closed-mouth (nasal) and open-mouth (oral) contact calls and examined individuality of the most usual oral calls of 19 Siberian wapiti (9 hinds and 10 5\–6-month adolescents) emitted in response to mother-offspring separation. In the oral calls, the values of frequency and power variables were higher than in the nasal calls. Calls of hinds and adolescents did not differ by the maximum fundamental frequency and duration, whereas the peak frequency was higher in the young. Discriminant function analysis (DFA) based on 11 acoustic variables of oral calls accurately classified to individual 92.5\% of hind calls and 96.9\% of adolescent calls (chi-square test for differences between hinds and adolescents, p = 0.19). Variables mainly contributing to vocal identity (duration, start, and maximum fundamental frequency) were the same in calls of mothers and adolescents. We conclude that similarities in the acoustics calls of mothers and adolescents mean that they do not differ in their potential for encoding individual identity, suggesting a mutual process of mother-offspring vocal recognition in Siberian wapiti.

}, doi = {10.1111/eth.2018.124.issue-1010.1111/eth.12804}, url = {http://doi.wiley.com/10.1111/eth.2018.124.issue-10}, author = {Sibiryakova, Olga V. and Volodin, Ilya A. and Volodina, Elena V.}, editor = {Wright, J.} } @article {53256, title = {Testosterone pulses at the nest site modify ultrasonic vocalization types in a monogamous and territorial mouse}, journal = {Ethology}, volume = {124}, year = {2018}, pages = {804{\textendash}815}, abstract = {

Modulation of baseline testosterone (T) via long-lasting T implants alters territorial, sexual, and social behavior of animals in the field. Transient T increases occur in numerous species after social interactions, but these transient increases in T have not been manipulated in the field. In the laboratory, these T increases can influence future behavior for days, causing changes in social behavior and inducing preferences for specific locations. We manipulated transient increases in T in the field at the nests of the monogamous and territorial California mouse (Peromyscus californicus) to examine long-term (\>24 hr) changes in ultrasonic vocalizations (USVs). Males of bonded male\–female dyads (=pair) were administered a T injection (vs. saline) three times over seven days and USVs of the male\–female dyad were measured for three days after the last injection. At T nests, the male\–female dyad produced significantly more 1SV (one call SV: an SV is a sustained vocalization that is long in duration and low in modulation) and 4SV (four call SV) type USVs than controls, but no significant changes in aggressive barks. Overall, male\–female dyad mice at T nests produced a greater diversity in call types such that 1SV, 4SV, 5SV, and a complex sweep were produced at T nests but not control nests. There were significantly more USVs produced at T nests on night 2 after the final injection. There were no differences in spectral characteristics of SV calls or aggressive barks between T and control nests. The function of the changes that occurred is unknown, but is consistent with increased long-term changes in behavioral interactions with nest mates and may reflect T-induced conditioned place preferences to the nest site. Significantly, transient increases in T influence future acoustic communication under field conditions with competing biotic and abiotic stimuli.

}, keywords = {androgens, conditioned place preference, field, male-female dyad, pair bond, Peromyscus californicus, social behavior, vocal communication}, doi = {10.1111/eth.12812}, author = {Timonin, Mary E and Kalcounis-Rueppell, Matina C and Marler, Catherine A} } @article {52569, title = {Male territorial aggression does not drive conformity to local vocal culture in a passerine bird}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-11-2017}, pages = {800 - 810}, abstract = {

In many songbird species, young individuals learn songs from neighbors and then settle nearby, thus creating neighborhoods of conformity to local vocal culture. In some species, individuals appear to postpone song learning until after dispersal, possibly to facilitate conformity to local dialects. Despite decades of study, we still lack a consensus regarding the selective pressures driving this delayed song learning. Two common hypothetical benefits to conformity, and thus delayed song learning, are rooted in territorial interactions; individuals preferentially produce local song either to avoid detection as new arrivals (deceptive mimicry) or to be more effectively recognized as conspecific territory holders. The dickcissel (Spiza americana) is an ideal species in which to study these hypotheses. Males of this species appear to delay song learning until they arrive at their first adult territory, each individual sings a single song type, and conformity to the local song culture is high. Using playback, we contradicted both of the territorial hypotheses described above; male dickcissels did not respond differentially to local vs foreign song playback treatment. We are confident in this lack of difference because dickcissels clearly responded less strongly to a third treatment, neighbor song, than to the other two treatments, demonstrating sufficient power in our experimental design (and providing the first evidence of the dear-enemy effect in dickcissels). Our results raise the question of why dickcissels respond equally aggressively to both local and foreign songs when other bird species often show reduced aggression toward foreign song. If reduced aggression to foreign song is not ubiquitous in species that achieve conformity through delayed learning, then selection from aggressive territorial interaction seems unlikely to be a general explanation for such delayed learning. Reduced aggression in response to foreign songs in other species may be due to reduced exposure to the stimulus of foreign song or to different cost-benefit trade-offs when responding to songs that deviate from the local average.

}, doi = {10.1111/eth.2017.123.issue-1110.1111/eth.12648}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-11}, author = {Parra, Marcelina and Dalisio, Anthony C. and Jensen, William E. and Parker, Timothy H.}, editor = {Koenig, W.} } @article {52568, title = {Variation in chick-a-dee calls of bridled titmice ( Baeolophus wollweberi): Frequent use of non-combinatorial calls in a combinatorial calling system}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-11-2017}, pages = {835 - 842}, doi = {10.1111/eth.2017.123.issue-1110.1111/eth.12657}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-11}, author = {Jung, Hwayoung and Freeberg, Todd M.}, editor = {Koenig, W.} } @article {52567, title = {Negative impact of urban noise on sexual receptivity and clutch size in female domestic canaries}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-11-2017}, pages = {843 - 853}, abstract = {

In oscines, male song stimulates female reproduction and females are known to adjust both their sexual preferences and their maternal investment according to song quality. Female domestic canaries are especially responsive to wide frequency bandwidth (4 kHz) male songs emitted with a high-repetition syllable rate and low minimal frequencies (1 kHz). We previously showed that low-frequency urban noise decreases female sexual responsiveness for these low-frequency songs (1\–5 kHz) through auditory masking. Based on the differential allocation hypothesis, we predicted that urban noise exposure will equally affect female maternal investment. Using a crossover design, we broadcast low-frequency songs to females either in an overlapping noise condition or in an alternating noise condition. Females decreased both their sexual responsiveness and their clutch size in the overlapping noise treatment relative to the alternative noise treatment. No differences were found concerning egg size or egg composition (yolk and albumen mass, testosterone concentration). Due to our experimental design, we can exclude a general impact of noisy conditions and thereby provide evidence for a detrimental effect through masking on avian courtship and reproductive output. These results suggest that noisy conditions may also affect avian communication in outdoor conditions, which may partly explain field reports on noise-dependent breeding success and reduced breeding densities at noisy sites.

}, doi = {10.1111/eth.2017.123.issue-1110.1111/eth.12659}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-11}, author = {Huet des Aunay, Guillaume and Grenna, Marco and Slabbekoorn, Hans and Nicolas, Pierre and Nagle, Laurent and Leboucher, G{\'e}rard and Malacarne, Giorgio and Draganoiu, Tudor I.}, editor = {Fusani, L.} } @article {52566, title = {Grunt to go-Vocal coordination of group movements in redfronted lemurs}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-12-2017}, pages = {894 - 905}, abstract = {

To remain cohesive as a group, individuals must coordinate their movements between resources. In many species, vocalisations are used in this context. While some species have specific movement calls, others use calls which are also employed in different contexts. The use of such multicontextual calls has rarely been studied quantitatively, especially during both the pre-departure and departure period associated with collective decisions. We thus investigated the use of close calls (\“grunts\”) for the coordination of collective movements in four groups of wild redfronted lemurs (Eulemur rufifrons) in Kirindy Forest, Western Madagascar. Group movements are started by an initiator, who moves away from the group and is joined by followers setting out in the same direction. We observed collective movements and recorded vocalisations from 18 focal individuals (54 movements recorded for followers, 21 for initiators). The grunt rate of both initiators and followers was higher in the pre-departure period than in a control context (i.e., during foraging). Initiators of collective movements grunted more often than followers in the pre-departure period as well as at individual departure. The latter difference was due to the initiators\’ grunt rates increasing earlier than the followers\’ and remaining at an elevated level for longer. These observations suggest that grunts serve to coordinate the departure by indicating the individual\&$\#$39;s readiness to move. The pre-departure period, in which both initiators and followers showed an elevated grunt rate, may provide the basis for a shared decision on departure time. The difference in initiator and follower call rates suggests that grunts may have a recruitment function, but playback experiments are required to test this potential function. Overall, our study describes how multicontextual close calls can function as movement calls, with changes in call rate providing a potential feedback mechanism for the timing of group movements. This study thus contributes to a more detailed understanding of the mechanisms of group coordination and collective decision-making.

}, doi = {10.1111/eth.2017.123.issue-1210.1111/eth.12663}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-12}, author = {Sperber, Anna Lucia and Werner, Lynne M. and Kappeler, Peter M. and Fichtel, Claudia}, editor = {Wright, J.} } @article {52565, title = {Bottlenose dolphins that forage with artisanal fishermen whistle differently}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-12-2017}, pages = {906 - 915}, abstract = {

Acoustic communication is a taxonomically widespread phenomenon, crucial for social animals. We evaluate social sounds from bottlenose dolphins (Tursiops truncatus) of Laguna, southern Brazil, whose social structure is organized around a cooperative foraging tactic with artisanal fishermen. This tactic involves stereotyped and coordinated behaviour by dolphins and fishermen and is performed by a subset of the dolphin population, splitting it into two distinct social communities. We compared the acoustic parameters and type of whistles emitted by dolphins of the \“non-cooperative\” and \“cooperative\” communities, both during their interactions with fishermen and in times where dolphins were engaged in other types of foraging. Our findings show how dolphins\’ social sounds differ between foraging tactics and social communities. The frequencies of six whistle types (ascending, descending, concave, convex, multiple, flat) were significantly dependent on tactics and communities. Ascending whistles were more common than expected during foraging without fishermen, and among dolphins of the non-cooperative community. Whistle acoustic parameters (duration, number of inclination changes and inflection points, and initial, final, maximum, minimum frequencies) also varied between social communities. In general, whistles emitted by cooperative dolphins, mainly when not interacting with fishermen, tended to be shorter, had higher frequency and more inflections than those emitted by non-cooperative dolphins. These results suggest that different whistles may convey specific information among dolphins related to foraging, which we hypothesize promote social cohesion among members of the same social community. These differences in acoustic repertoires add a new dimension of complexity to this unique human\–animal interaction.

}, doi = {10.1111/eth.2017.123.issue-1210.1111/eth.12665}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-12}, author = {Romeu, Bianca and Cantor, Mauricio and Bezamat, Carolina and Sim{\~o}es-Lopes, Paulo C. and Daura-Jorge, F{\'a}bio G.}, editor = {Ebensperger, L.} } @article {52564, title = {Behavioural response evoked by conspecific distress calls in two neotropical treefrogs}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-12-2017}, pages = {942 - 948}, abstract = {

Anurans emit distress calls when attacked by predators as a defensive mechanism. As distress calls may trigger antipredator behaviour even in individuals that are not under attack, we tested whether this defensive behaviour induced behavioural changes in neighbouring conspecifics. We compared the behavioural responses of two species of Neotropical hylid frogs (genus Boana) to conspecific distress calls and white noise. Individuals of both species interrupted their vocal activity and decreased call rate after hearing the distress call. Natural variation on signal intensity calibrated among the nearest neighbours did not influence the response and we did not observe negative phonotaxis after any acoustic stimulus. Despite the fact that many predators are acoustically oriented, we could not determine if such response (reduced call rate) was induced by risk assessment or by the masking effect on advertisement calls. Boana faber responded similarly to white noise and distress calls, while B. bischoffi responded more intensely to distress calls. Duration of silence after playbacks in B. faber was longer than B. bischoffi. We suggest that, if the signals are interpreted as a risk cue by neighbouring conspecifics, each species may be preyed upon by different predators, as they may have led to distinct defensive strategies and different responses to distress calls. If risk assessment information is included in distress calls, it triggers behavioural responses only in the nearest neighbours, as we did not observe responses on the vocal activity of the interspecific chorus. Our results add relevant data about acoustic communication and interpretations by anurans, highlighting the importance of considering cues within common and widespread signals.

}, doi = {10.1111/eth.2017.123.issue-1210.1111/eth.12693}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-12}, author = {Forti, Lucas Rodriguez and Forti, Anna B{\'a}rbara Bella Sanches and M{\'a}rquez, Rafael and Lu{\'\i}s Felipe Toledo}, editor = {Foster, S.} } @article {52563, title = {Do birds differentiate between white noise and deterministic chaos?}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-12-2017}, pages = {966 - 973}, abstract = {

Noisy, unpredictable sounds are often present in the vocalizations of fearful and stressed animals across many taxa. A variety of structural characteristics, called nonlinear acoustic phenomena, that include subharmonics, rapid frequency modulations, and deterministic chaos are responsible for the harsh sound quality of these vocalizations. Exposure to nonlinear sound can elicit increased arousal in birds and mammals. Past experiments have used white noise to test for effects of deterministic chaos on perceivers. However, deterministic chaos differs structurally from white noise (i.e., random signal with equal energy at all frequencies), and unlike white noise, may differ dramatically depending on how it is produced. In addition, the subtle structural variation of chaos may not be distinguishable in the environment due to the attenuation and degradation of sound over distance and different habitat types. We designed two experiments to clarify whether American robins (Turdus migratorius) and warbling vireos (Vireo gilvus) discriminate between white noise and deterministic chaos. We broadcast and re-recorded white noise and two exemplars of deterministic chaos\—one generated with a Chua oscillator and the other generated using a logistic equation\—at 1, 10, 20, 30, 40, and 80 m across open and forested habitat and used spectrogram correlations to compare stimuli along this degradational gradient. We found that sounds degraded similarly in both habitats when compared to a reference distance of 1 m. Comparing pairs of stimuli across distances suggested that Chua chaos was more easily distinguishable from noise and logistic chaos. In addition, all stimuli became more distinctive over increased distance. The second experiment tested behavioral responses of robins and warbling vireos to control sounds of tropical kingbird (Quiscalus mexicanus), white noise, and two exemplars of deterministic chaos (Chua and logistic). Neither American robins nor warbling vireos responded differently to at least two types of deterministic chaos and white noise, validating previous playback studies that used white noise as a surrogate for deterministic chaos. Uniform responses to a variety of nonlinear features in these birds possibly reflect error management in alarm signal detection.

}, doi = {10.1111/eth.2017.123.issue-1210.1111/eth.12702}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-12}, author = {Blumstein, Daniel T. and Whitaker, Jessica and Kennen, Judith and Bryant, Gregory A.}, editor = {Koenig, W.} } @article {50509, title = {Male tree weta are attracted to cuticular scent cues but do not discriminate according to sex or among two closely related species}, journal = {Ethology}, year = {2017}, month = {May-08-2018}, abstract = {

Recognition of conspecifics is an essential precursor of successful mating. Where related species coexist, species discrimination might be important, but because related species are similar, species signal recognition may actually be low. Chemical cues such as cuticular hydrocarbons (CHCs) are frequently used by insects to identify suitable sexual partners. We predicted that New Zealand tree weta ( Hemideina spp.), a genus of nocturnal ensiferan Orthoptera that live both allopatrically and sympatrically, use chemical signals from either frass or CHCs to find mates. In a series of six laboratory trials using both H. thoracica and H. crassidens , we found that male tree weta, but not female tree weta, occupied cavities primed with female cuticular cues more often than cavities without. However, males did not discriminate between chemical cues of male and female conspecifics, or between conspecifics and heterospecifics. In field trials, tree weta did not occupy artificial cavities primed with either female frass or female cuticular cues more often than unscented cavities. However, in both trials weta pref- erentially returned to cavities that had already been occupied earlier in the trials. A final field trial confirmed the presence of mixed species harems during the mating season in one region of sympatry. Our results suggest that selection on sex and spe- cies specific chemical cues that could be used to find conspecific mates is weak. Mixed species aggregations suggest that identification of conspecific mating cues has not evolved to be species specific. We infer that for male tree weta, the cost of mating with heterospecifics is likely less than not mating at all.

}, keywords = {cuticular hydrocarbons, hybridization, Orthoptera, reproductive interference, signal, species recognition}, doi = {10.1111/eth.12652}, url = {http://doi.wiley.com/10.1111/eth.12652}, author = {Wehi, Priscilla M. and Monks, Adrian and Morgan-Richards, Mary}, editor = {Tregenza, T.} } @article {50506, title = {Responses of male cricket frogs ( Acris crepitans) to attenuated and degraded advertisement calls}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-05-2017}, pages = {357 - 364}, abstract = {

We examined the vocal and non-vocal responses of male cricket frogs (Acris crepitans) to conspecific advertisement calls that had been attenuated or degraded by reducing the depth of amplitude modulation (AM). Both are characteristic of changes to the call as it is transmitted through natural habitats. As stimulus calls became more intense or less degraded, male cricket frogs gradually decreased their call rate and increased the number of call groups and pulse groups in their calls, changes indicative of increased aggressive interactions. At the higher intensities and lower degradation levels, the probability that males would shift to one of two non-vocal behavioral responses, attacking the perceived intruder or ceasing calling and abandoning the call site, gradually increased. The results show that differences in signal attenuation and AM degradation levels are perceived by males and trigger both vocal and non-vocal behavioral responses consistent with their use in evaluating the distance to a challenging male. Furthermore, the results indicate that the male responses are graded, increasing as intensity rises and degradation falls, and hierarchical, with vocal responses preceding behavioral responses over the range of intensities and degradation levels presented.

}, keywords = {acoustic communication, aggression, amphibians, cricket frogs}, doi = {10.1111/eth.2017.123.issue-510.1111/eth.12602}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-5}, author = {Venator, Kurt R. and Michael J. Ryan and Wilczynski, Walter}, editor = {Koenig, W.} } @article {50505, title = {Individuality of distress and discomfort calls in neonates with bass voices: Wild-living goitred gazelles ( Gazella subgutturosa) and saiga antelopes ( Saiga tatarica)}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-05-2017}, pages = {386 - 396}, abstract = {

Neonate ruminants produce distress calls when captured by a predator and discomfort milk begging calls when hungry. In many neonate ruminants, the distress and discomfort calls are high-frequency vocalizations, in which the fundamental frequency is the key variable for recognition of their emotional arousal by caregivers. In contrast, in this study, we examine the low-frequency open-mouth distress and discomfort calls in the neonates of two species of wild-living ungulates, which clearly highlight vocal tract resonances (formants). In the goitred gazelle (Gazella subgutturosa), the distress calls were higher in fundamental frequency (f0) and in the first and third formants than the discomfort calls. The accuracy of classifying individuals by variables of distress calls with discriminant function analysis (67\%) was significantly lower than that of discomfort calls (85\%). In the saiga (Saiga tatarica), only the third formant was higher in the distress calls than in the discomfort calls. The accuracy of classifying individuals by variables of distress calls (89\%) did not differ significantly from that of discomfort calls (94\%). Thus, the use of acoustic cues to vocal identity and to the degree of arousal differs between the two species. Calls were significantly more individualistic in the saiga, probably because this species lives in large herds and neonates use a \‘following\’ antipredatory strategy, in which vocal individuality is crucial for mother\–offspring communication. In contrast, goitred gazelles live in smaller groups and neonates use a \‘hiding\’ antipredatory strategy. Accordingly, mothers can rely on additional environmental cues for spotting their young and this may decrease the necessity for individualization of the calls of neonates.

}, keywords = {acoustic behavior, antipredatory strategy, emotional arousal, mother-offspring communication, ruminants, vocal identity}, doi = {10.1111/eth.2017.123.issue-510.1111/eth.12607}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-5}, author = {Volodin, Ilya A. and Sibiryakova, Olga V. and Frey, Roland and Efremova, Kseniya O. and Soldatova, Natalia V. and Zuther, Steffen and Kisebaev, Talgat B. and Salemgareev, Albert R. and Volodina, Elena V.} } @article {50494, title = {Subharmonics increase the auditory impact of female koala rejection calls}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-08-2017}, pages = {571 - 579}, abstract = {

Although non-linear phenomena are common in human and non-human animal vocalisations, their functional relevance remains poorly understood. One theory posits that non-linear phenomena generate unpredictability in vocalisations, which increases the auditory impact of vocal signals, and makes animals less likely to habituate to call repetition. Female koalas (Phascolarctos cinereus) produce vocal signals when they reject male copulation attempts that contain relatively high levels of non-linear phenomena, and thus may function as attention grabbing vocal signals during the breeding season. To test this hypothesis, we used playback experiments: firstly, to determine whether female rejection calls induce heightened behavioural responses in free-ranging male koalas during the breeding season, and secondly, to examine how the relative amount of non-linear phenomena in rejection calls influences male behavioural response. The results show that male koalas look for longer towards speakers broadcasting playback sequences of male bellows followed by a series of female rejection calls than those broadcasting only male bellows. In addition, female rejection call sequences with more subharmonics, higher harmonics-to-noise ratios, and less biphonation produced the greatest male looking responses. Our findings support the hypothesis that female koala rejection calls function to grab male attention during the breeding season, and indicate that subharmonics are the main acoustic feature that increases the auditory impact of these vocal signals.

}, keywords = {koalas, mammal vocal communication, non-linear phenomena}, doi = {10.1111/eth.2017.123.issue-810.1111/eth.12628}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-8}, author = {Charlton, Benjamin D. and Watchorn, Darcy J. and Whisson, Desley A.} } @article {50493, title = {Alarm call-based discrimination between common cuckoo and Eurasian sparrowhawk in a Chinese population of great tits}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-08-2017}, pages = {542 - 550}, abstract = {

Morphological resemblance of the common cuckoo Cuculus canorus to the Eurasian sparrowhawk Accipiter nisus has been regarded as an example of predator mimicry. Common hosts could distinguish parasites as the result of coevolution, while rare hosts or non-hosts may mistake cuckoos for hawks because rare hosts or non-hosts behave similarly when faced with these two species. Birds usually produce alarm calls in addition to showing behavioral responses when in danger. However, previous studies of identification by rare hosts or non-hosts of sparrowhawks usually lacked experimental evidence of alarm calls. Great tits Parus major, a rare cuckoo host, perform similar behaviors and usually produce alarm calls in response to sparrowhawks and common cuckoos. Here, we tested whether great tits could distinguish common cuckoo from sparrowhawk based on analysis of their alarm calls and the effects of playback of alarm calls on conspecific behavior. Previous studies showed that great tits have a complex communication system that conveys information about predators, and they could perform different kinds of response behavior to different alarm calls. If great tits have not made the ability to distinguish between common cuckoo and sparrowhawk, then their acoustic responses to these two species and their response behaviors in playback experiments should be similar. Specimens of a common cuckoo (parasite), a sparrowhawk (predator) and an Oriental turtle dove Streptopelia orientalis (harmless control) were used to elicit and subsequently record the response behavior and alarm calls of great tits. There was no significant difference in behavioral response among great tits when exposed to the dummy of cuckoo, sparrowhawk and dove. In contrast, they differed significantly in alarm calls. Great tits produced more notes per call that contained increasing D-type and decreasing I-type notes when responding to sparrowhawk as compared to cuckoo or dove. In playback experiments, we found that great tits responded more strongly to great tit hawk than to great tit cuckoo or great tit dove alarm calls. Our study suggests that great tits are able to distinguish sparrowhawks from common cuckoos and convey relevant information in alarm calls by adjusting the number and combinations of notes of a single call type.

}, doi = {10.1111/eth.2017.123.issue-810.1111/eth.12624}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-8}, author = {Yu, Jiangping and Xing, Xiaoying and Jiang, Yunlei and Liang, Wei and Wang, Haitao and Anders Pape M{\o}ller} } @article {50492, title = {The effects of cultural drift on geographic variation in echolocation calls of the Chinese rufous horseshoe bat ( Rhinolophus sinicus)}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-08-2017}, pages = {532 - 541}, abstract = {

Drift, selection, or their combined effects commonly drive geographic variation in traits. Clarifying the relative roles of each process is a long-standing research goal in evolutionary biology. Acoustic signals of bats are a phenotypic characteristic that plays an important role in social organization and species recognition. We extensively sampled the Chinese rufous horseshoe bat (Rhinolophus sinicus) throughout China and Vietnam and reconstructed a species phylogeny to better understand the patterns and causes of the geographic variation of acoustic signals. Our results showed that the resting frequency (RF) of calls varied with latitude, sex, and distance among different colony locations. RF differences were not correlated with genetic distance (based on only one nuclear locus and the mitochondrial locus), climatic factors (mean annual temperature and mean annual precipitable water), or body size, although differences in calls increased with distance among various populations. This suggests that cultural drift may play more important roles than genetic drift and acoustic adaptation in shaping acoustic differences within regions in R. sinicus.

}, keywords = {drift, geographic variation, resting frequency, Rhinolophus sinicus, selection}, doi = {10.1111/eth.2017.123.issue-810.1111/eth.12627}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-8}, author = {Xie, Lifen and Sun, Keping and Jiang, Tinglei and Liu, Sen and Lu, Guanjun and Jin, Longru and Feng, Jiang} } @article {50491, title = {Sexual differentiation and seasonal variation in response to conspecific and heterospecific acoustic signals}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-06-2017}, pages = {460 - 466}, abstract = {

Interspecific territoriality is frequently reported between closely related species; however, few studies have demonstrated interspecific territoriality between distantly related species living in sympatry. We conducted playback experiments to investigate territorial behaviour in male and female White-bellied Wrens (Uropsila leucogastra) in response to simulated conspecific and heterospecific intruders during the breeding and non-breeding seasons. We explored whether heterospecific songs of the Happy Wren (Pheugopedius felix), a distantly related species and ecological competitor, elicited antagonistic responses from focal White-bellied Wrens, and whether such responses differed between the sexes. We also examined whether male and female responses to conspecific and heterospecific rivals varied with season. We found that male White-bellied Wrens always responded to conspecific song, and responded significantly more to heterospecific song compared to a control stimulus (Tropical Parula, Setophaga pitiayumi). In contrast, although female White-bellied Wrens responded strongly to conspecific song, their response to heterospecific song did not differ significantly from the control stimulus. The proportion of males that responded to heterospecific songs and the proportion of females that responded to conspecific songs varied seasonally, showing significantly lower responses during the breeding season. The intense responses of male White-bellied Wrens to playback of heterospecific songs suggest that they recognise ecological competitors based on their vocal signals. Furthermore, the decrease in agonistic interactions during the breeding season is in line with the hypothesis that aggressive behaviour may be detrimental to reproductive and parental activity, and the hypothesis that heterospecific animals pose less of a threat during the breeding season.

}, doi = {10.1111/eth.12616}, url = {http://doi.wiley.com/10.1111/eth.12616}, author = {Sosa-L{\'o}pez, J. Roberto and Mennill, Daniel J. and Renton, Katherine}, editor = {Koenig, W.} } @article {50490, title = {No need to shout: Effect of signal loudness on sibling communication in barn owls Tyto alba}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-06-2017}, pages = {419 - 424}, abstract = {

In animal communication, signal loudness is often ignored and seldom measured. We used a playback experiment to examine the role of vocal loudness (i.e., sound pressure level) in sibling to sibling communication of nestling barn owls Tyto alba. In this species, siblings vocally negotiate among each other for priority access to parental food resources. Call rate and call duration play key roles in this vocal communication system, with the most vocal nestlings deterring their siblings from competing for access to the food item next delivered by parents. Here, we broadcast calls at different loudness levels and call rate to live nestlings. The loudness of playback calls did not affect owlets\&$\#$39; investment in call rate, call duration or call loudness. The rate at which playback calls were broadcast affected owlets\&$\#$39; call rate but did not influence their response in terms of loudness. This suggests that selection for producing loud signals may be weak in this species, as loud calls may attract predators. Moreover, given that owlets do not overlap their calls and that they communicate to nearby siblings in the silence of the night, loud signals may not be necessary to convey reliable information about food need.

}, keywords = {acoustics, amplitude, begging, communication, competition, multiple signals, negotiation, playbacks}, doi = {10.1111/eth.12612}, url = {http://doi.wiley.com/10.1111/eth.12612}, author = {Dreiss, Am{\'e}lie N. and Ducouret, Pauline and Ruppli, Charl{\`e}ne A. and Rossier, Virginie and Hernandez, Lucile and Falourd, Xavier and Marmaroli, Patrick and Cazau, Dorian and Lissek, Herv{\'e} and Roulin, Alexandre}, editor = {Fusani, L.} } @article {50304, title = {Restricted responsiveness to noise interference in two anurans from the southern temperate forest}, journal = {Ethology}, year = {2017}, month = {Feb-08-2018}, abstract = {

Animals adopt different strategies to communicate by means of sound in noisy envi - ronments such that some species increase, while others decrease their vocal activity in the presence of interference. Anuran amphibians from diverse latitudes exhibit both kinds of responses. Recent studies have shown that males of Batrachyla taeniata and Batrachyla antartandica from the temperate austral forest do not call in response to the presentation of advertisement calls of sympatric congeneric species. In contrast, Batrachyla leptopus responds to these signals in a similar way as to conspecific calls. The responsiveness of B. taeniata to natural abiotic interference has also been tested and found that noises of such sources produce strong increases in vocal activity. To assess the diversity in responsiveness to acoustic intrusion in this group, we exposed males of B. leptopus and B. antartandica to prolonged pre- recorded natural abiotic noises of wind, creek, rain, and to a band- pass noise centered at 2,000 Hz, at 67 dB Sound Pressure Level (SPL). The subjects did not increase their vocal activity signifi - cantly when exposed to these sounds and to band- pass noise at increasing intensities (55\–79 dB SPL). These results contrast with the increase in vocal activity observed previously in B. taeniata to continuous abiotic noise and point to the existence of di - verse strategies to confront acoustic intrusion among related species. The lack of vocal activation observed also contrasts with the responsiveness of B. leptopus to het- erospecific signals, but parallels the lack of response to such sounds in B. antartandica . Furthermore, the results obtained contrast with the responsiveness of these species to synthetic prolonged sounds observed in previous studies, suggesting that the modes of responses to acoustic intrusion may depend on previous experience, rather than having a species- specific nature.

}, keywords = {abiotic noise, acoustic interference, anurans, austral temperate forest, sound communication}, doi = {10.1111/eth.12644}, url = {http://doi.wiley.com/10.1111/eth.12644}, author = {Penna, Mario and Cisternas, Javiera and Toloza, Jessica}, editor = {Foster, S.} } @article {20926, title = {A Comparative Study of Mating Behaviour in Some Neotropical Grasshoppers (Acridoidea)}, journal = {Ethology}, volume = {76}, year = {1987}, month = {Dec-01-1987}, pages = {265 - 296}, abstract = {

Aspects of premating and mating behaviour in several South American grasshopppers (Acridoidea) are described and compared. Examples of communication by acoustical, visual and chemical means are given.

Acoustic signals are emitted only by species of the subfamilies Gomphocerinae, Acridinae, Romaleinae and Copiocerinae. Each subfamily has distinct sound-producing mechanisms, and the songs occur in different behavioural contexts. In Gomphocerinae and Acridinae the sexes recognize and attract each other by species-specific songs produced by a femuro-tegminal stridulatory mechanism. In contrast, Romaleinae produce a simple song by rubbing the hindwings against the forewings. These songs are similar in different species and no attraction of females could be demonstrated, but the behaviour may function in male-male interaction and during copulation. Sexual pheromones also play a role in this subfamily. Acoustic activity during copulation has been observed in Aleuasini (Copiocerinae), but its function is still unclear.

No sound production at all exists in the Leptysminae, Rhytidochrotinae, Ommatolampinae, Melanoplinae, Proctolabinae and Bactrophorinae, but conspicuous movements of hindlegs (kneewaving) and antennae were observed. In some species these form part of a soundless courtship display.

Ecological constraints have little influence on the basic mating strategies: romaleine, gomphocerine and melanopline grasshoppers often coexist in various habitats, but show the divergent behaviour patterns characteristic of their respective subfamilies. Intrinsic factors of female reproductive physiology seem to be more important: a hormonally controlled reproductive cycle in gomphocerine females provides for only few short copulations, while romaleine females copulate frequently and longer. In Gomphocerinae and Acridinae, receptive females are rare (male-biased operational sex ratio) which leads to intense competition among males. It is hypothesized that this could be responsible for the high diversification of song and courtship patterns in these subfamilies.

}, doi = {10.1111/eth.1987.76.issue-410.1111/j.1439-0310.1987.tb00689.x}, url = {http://blackwell-synergy.com/doi/abs/10.1111/eth.1987.76.issue-4}, author = {Riede, Klaus} } @article {17236, title = {Confusion of Phonotaxis by Masking Sounds in the Bushcricket Conocephalus brevipennis (Tettigoniidae: Conocephalinae)}, journal = {Ethology}, volume = {73}, year = {1986}, month = {Dec-01-1986}, pages = {19 - 28}, abstract = {

Female Conocephalus brevipennis, executing phonotaxis to the call of a conspecific male broadcast from a speaker, were subjected to varying levels of background sound so as to progressively mask the attracting signal. The background consisted of either random noise or the call of a sympatric congener, C. nigropleurum and was delivered from above the orienting female. Disruption of phonotaxis was assayed by monitoring the angular dispersion of the female\&$\#$39;s exit path from the arena, relative to the position of the conspecific call. Random noise significantly interfered with phonotaxis when it was within 2 dB of the conspecific call intensity, both signals measured at the centre of the arena. The equivalent effect of the call C. nigropleurum was 5 dB above conspecific call intensity. The implication of signal loss within background noise is discussed as are the possible interactive behaviours of competing sympatric syntopic species.

}, doi = {10.1111/eth.1986.73.issue-110.1111/j.1439-0310.1986.tb00996.x}, url = {http://blackwell-synergy.com/doi/abs/10.1111/eth.1986.73.issue-1}, author = {Winston J. Bailey and Glenn K. Morris} } @article {16470, title = {Divergence between the Courtship Songs of the Field Crickets Gryllus texensis and Gryllus rubens (Orthoptera, Gryllidae)}, journal = {Ethology}, volume = {107}, year = {2001}, month = {May-12-2003}, pages = {1075 - 1085}, issn = {0179-1613}, doi = {10.1046/j.1439-0310.2001.00730.x}, url = {http://doi.wiley.com/10.1046/j.1439-0310.2001.00730.xhttps://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046\%2Fj.1439-0310.2001.00730.x}, author = {Fitzpatrick, Mark J. and Gray, David A.} }