Vibroscape analysis reveals acoustic niche overlap and plastic alteration of vibratory courtship signals in ground-dwelling wolf spiders

Abstract

Abstract Soundscape ecology has enabled researchers to investigate natural interactions among biotic and abiotic sounds as well as their influence on local animals. To expand the scope of soundscape ecology to encompass substrate-borne vibrations (i.e. vibroscapes), we developed methods for recording and analyzing sounds produced by ground-dwelling arthropods to characterize the vibroscape of a deciduous forest floor using inexpensive contact microphone arrays followed by automated sound filtering and detection in large audio datasets. Through the collected data, we tested the hypothesis that closely related species of Schizocosa wolf spider partition their acoustic niche. In contrast to previous studies on acoustic niche partitioning, two closely related species - S. stridulans and S. uetzi - showed high acoustic niche overlap across space, time, and/or signal structure. Finally, we examined whether substrate-borne noise, including anthropogenic noise (e.g., airplanes) and heterospecific signals, promotes behavioral plasticity in signaling behavior to reduce the risk of signal interference. We found that all three focal Schizocosa species increased the dominant frequency of their vibratory courtship signals in noisier signaling environments. Also, S. stridulans males displayed increased vibratory signal complexity with an increased abundance of S. uetzi, their sister species with which they are highly overlapped in the acoustic niche.