Fowler-Finn, K. D. | Search bioRxiv

bioRxiv2026

Mating display plasticity predicts the biogeography of complex communication and population persistence in changing climates

Animals often produce complex combinations of signals to enhance display detection, interpretation, and the information conveyed during communication. Combined signals can serve many functions in communication systems, but we know little about how signal combinations initially evolve and why they often vary in complexity across broad geographic gradients. Here, we show that environmentally driven changes in the coordinated production of multiple signals determine whether the signals can interact in functional ways, and thereby shape the capacity for selection to favor increased display complexity. Our behavioral experiment in a focal species of Schizocosa wolf spider reveal that shifts to hotter and wetter environments can enable males with exaggerated morphological ornaments to also produce exaggerated courtship behaviors, allowing these signals to interactively affect mating success. Congruently, phylogenetic analyses show that species in hotter and wetter regions of North America have repeatedly evolved more complex courtship displays alongside exaggerated morphological ornaments. Biogeographic analyses further suggest that geographic gradients in display complexity may arise not only from in situ evolution, but also from more frequent establishment of species with complex displays in hotter and wetter regions. Finally, we found that species with complex displays were more likely to persist in areas that have faced more severe climate warming and intensified precipitation in the last 50 years--conditions that should enhance the functioning of complex mating displays for reproductive success. Altogether, our findings reveal a novel association between plasticity in inter-signal interactions and variation in the complexity of communication systems across scales of biological organization.

evolutionary biology↗

bioRxiv2024

Temperature effects on interspecific eavesdropping in the wild

Mating signals are targets of conspecific signal recognition and sexual selection, but are also subject to abiotic temperature effects and to biotic interspecific eavesdroppers. In crickets, the male calling song becomes faster at warmer temperatures, and female crickets recognition of male song tracks temperature in a coordinated manner, termed temperature coupling. But female crickets are not the only ecologically relevant listeners: some cricket species are parasitized by Ormia ochracea, a parasitoid fly which finds its cricket hosts by eavesdropping on male cricket song. How temperature affects parasitoid fly phonotaxis to song is largely unexplored, with only one previous study conducted under field conditions. Here we explore six possible patterns of thermal effects on fly responses to cricket song, including temperature coupling, using field playbacks of synthetic Gryllus lineaticeps songs designed to be species-typical at various temperatures. We find that temperature does affect fly response, but that the temperature deviation of songs from ambient does not impact numbers of flies caught. We extend this finding by comparing the temperatures of the air and ground to show that temperature coupling is unlikely to be effective given microhabitat variation and differential rates of cooling in the evening hours when flies are most active. Our results can be interpreted more broadly to suggest (i) temperature effects on intraspecific communication systems may be more tightly coupled than are effects on interspecific eavesdropping, and (ii) variation in thermal microhabitats in the field make it difficult to translate laboratory physiological responses to natural selection in the wild. Lay SummaryMating signals and signal recognition change with temperature, and sometimes mating signals are intercepted by predators or parasites. By using playbacks of cricket song in the wild, we show that temperature changes do affect the response of a parasitoid fly to cricket song. However, parasitoid responses are not tightly coupled to temperature induced changes in cricket song, in part due to unpredictable variation in microhabitat temperatures typical of crickets and flies.

animal behavior and cognition↗