@article {57934, title = {Spatial Mixing between Calling Males of Two Closely Related, Sympatric Crickets Suggests Beneficial Heterospecific Interactions in a NonAdaptive Radiation}, year = {2019}, abstract = {

Sympatry among closely related species occurs in both adaptive and nonadaptive radiations. Among closely related, sympatric species of a nonadaptive radiation, the lack of ecological differentiation brings species into continual contact where individuals are exposed to the risk of reproductive interference. Selection thus should cause divergence in multiple components mediating the reproductive boundary. Besides differentiation of reproductive signals per se, spatial segregation is a commonly proposed mechanism that can mitigate reproductive interference. Studying a pair of broadly sympatric, closely related cricket species from a nonadaptive radiation in Hawaii, we 1) quantified acoustic divergence of male songs and 2) tested alternative hypotheses of spatial distribution of calling males of the 2 species. Acoustic analyses of the recorded songs showed that, while the 2 species differed substantially in pulse rate, no spectral or fine temporal segregation of the pulse structure was evident, indicating the potential for acoustic masking. Moreover, we found that calling males of the 2 species are highly mixed both vertically and horizontally and showed the same preference for calling sites. More surprisingly, calling males were found to form mixed-species calling clusters where heterospecific males are closer to each other than conspecific males. Such an individual spacing pattern suggests low heterospecific aggression and/or high conspecific competition. Because females prefer higher sound intensity, heterospecific males may benefit, rather than interfere, with each other in attracting females. These findings offer a potential mechanism enabling species coexistence in sympatry.

}, keywords = {neighbor spacing, nonadaptive radiation, reproductive barrier, signaling site choice, spatial segregation, sympatric species}, doi = {10.1093/jhered/esz062}, url = {https://academic.oup.com/jhered/advance-article/doi/10.1093/jhered/esz062/5648033}, author = {Xu, Mingzi and Shaw, Kerry L} } @article {16466, title = {Acoustic preference functions and song variability in the Hawaiian cricket Laupala cerasina}, journal = {Proceedings of the Royal Society B: Biological Sciences}, volume = {267}, year = {2000}, month = {Oct-03-2001}, pages = {577 - 584}, abstract = {

Female preference functions for di\¡erent sexual traits can di\¡er signi\¢cantly, from {\textquoteleft}unimodal\’ to {\textquoteleft}open ended\’. Through the study of acoustic communication in anurans, several studies have reported an association between static (stereotyped) traits versus dynamic (variable) traits and preference function shape (unimodal versus open ended, respectively). Observing a similar pattern in a phylogenetically independent group would suggest that deterministic forces have caused a relationship between signal variability and preference function shape in acoustic signalling systems. We examined this phenomenon in crickets, another animal characterized by intersexual acoustic communication. We measured the within- male variability for three acoustic features of the male calling song in Laupala cerasina and the corresponding shape of the female preference function for each of these features. We o\¡er support for the generalization that open-ended preference functions correspond to relatively dynamic courtship traits and unimodal preference functions correspond to relatively static courtship traits. We discuss the evolutionary signi\¢cance of these \¢ndings in the context of the natural history of the Laupala species radiation.

}, keywords = {acoustic communication, crickets, mate recognition, preference, sexual selection, song}, issn = {0962-8452}, doi = {10.1098/rspb.2000.1040}, url = {http://rspb.royalsocietypublishing.org/cgi/doi/10.1098/rspb.2000.1040}, author = {Shaw, K. L. and Herlihy, D. P.} }