@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 {47779, title = {Effects of juvenile and adult condition on long-distance call components in the Jamaican field cricket, Gryllus assimilis}, journal = {Animal Behaviour}, volume = {81}, year = {2011}, month = {Jan-01-2011}, pages = {135 - 144}, abstract = {

Complex signals may arise through either content- or efficacy-based selection. Content-based signals are thought to evolve because of the information content they provide to the receiver. Such signals may function as multiple messages, each relaying different information or types of information. For example, some signals or signal components may indicate different aspects of condition, or condition at different life stages (quality signals), while others relay information on signaller location, or function in species recognition. Or they may act as redundant signals of overall condition, or as backup signals of the same aspect of condition. Efficacy-based signals are proposed to evolve because of the way in which they influence the production, transmission, reception or processing of the signal. We manipulated juvenile and adult condition in male Jamaican field crickets, Gryllus assimilis, to test whether changes in components of the male\’s long-distance acoustic mate attraction signal were consistent with content- or efficacy-based selection. Several call components exhibited condition-dependence, and may be under content-based selection. Interpulse duration, pulse rate and chirp duration appeared to honestly signal juvenile condition, while dominant frequency appeared to signal adult condition. Thus, these signal components appeared to be acting as multiple messages of quality. Pulse number, interchirp duration and chirp rate were highly stereotyped and probably function in species recognition. Call number increased with decreasing condition and was likely under efficacy-based selection. No call components appeared to have the potential to act as redundant signals.

}, keywords = {acoustic signal, complex signal, condition-dependence, content, efficacy, Field cricket, multiple messages, multiple signals, redundant signal, sexual selection}, issn = {00033472}, doi = {10.1016/j.anbehav.2010.09.024}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347210003933}, author = {Whattam, Emily M. and Bertram, Susan M.} }