Baffling behavior why don’t more crickets use acoustic tools


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


5-5  Sat Jan 2  Baffling behavior: why don’t more crickets use acoustic tools? Brandt, EE*; Duke, S; Wang, L; Mhatre, N; University of Western Ontario ebrandt3@uwo.ca

Why is tool use rare among insects? For example, a few species of tree crickets build acoustic baffles that nearly double their calling efficiency. Such baffle use could benefit many of the > 900 known cricket species, yet, no other crickets make baffles. It has been hypothesized that tool-use in insects is rare because tool-use is stereotyped and derived from similar pre-existing behaviors, and appropriate behaviors are rarely available. An alternative explanation is that tool-use lacks sufficient utility to drive its evolution in the first place. Here, to quantify the utility of acoustic tools, we investigated the sound production efficiency of cricket wings across the phylogeny. First, we measured wing sizes, shapes, and calling frequencies for species across the gryllid phylogeny. Next, we used finite element analysis to model the sound field emanating from cricket wings and song frequencies lying within the natural range. By mapping data from real crickets onto our predicted landscape of efficiency, we determined the theoretical highest maximum efficiency achievable at a given frequency, Finally, since the environment also dramatically affects how a call is propagated, we created a second set of models which incorporated acoustic transmission losses in different habitats and modeled sound propagation with different sender and receiver positions. Using these models, we could predict and quantify the probable utility of acoustic tool use among crickets, providing insight into the drivers behind the rarity of acoustic tools in crickets.

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