Seismic Signaling is Crucial for Female Mate Choice in a Multimodal Signaling Wolf Spider

Complex courtship signals can be dissected into distinct components that can either function independently or via interactions with one another. Male Rabidosa rabida wolf spiders use courtship displays that couple a seismic signal with the waving of an ornamented foreleg. While previous studies suggest that female R. rabida exhibit mate choice and that both the seismic and visual modalities are important in mating interactions, it remains unclear how variation in each component influences female mating decisions. To investigate this, we ran two separate experiments in which we manipulated (1) male diets, to induce variation in the seismic courtship signal, and (2) male foreleg color, to artificially induce variation in visual foreleg ornamentation. To determine the influence of variation in each component independently, females were paired with males in environments that allowed the detection of only the manipulated signal component (e.g. seismic signal only and visual signal only). Variability in the seismic signal alone influenced female mate choice, but variability in visual ornamentation alone did not. In a third experiment, we manipulated foreleg color and allowed it to interact with the seismic signal to determine whether inter-signal interactions influence female mating decisions. When females were able to detect both signal components, variation in visual ornamentation did influence mate choice females preferred ornamented males. Together, these results suggest that the seismic signal of male R. rabida is integral for female mate choice and that the components of the courtship display interact to influence female mating decisions.