DISSERTATION RESEARCH: Consequences of adaptive behavioral plasticity for selection on an acoustic signal

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A central problem in evolutionary biology is understanding how flexibility (termed plasticity) in the expression of traits functions when populations are under selection: does flexibility facilitate or hamper evolution? Flexibility could facilitate evolution by creating new traits on which selection could act; alternatively, flexibility could hamper evolution by protecting genes for detrimental traits from being selected. Flexibility in mating behavior can be especially important because it could allow the maintenance of small or isolated populations, where available mates of preferred types are few, or play a role in the divergence of populations, ultimately leading to divergence of one species into two or more. This project addresses this fundamental question by examining how flexibility in mate preference could affect the evolution of courtship. During this project, a graduate student and an undergraduate participant will gain comprehensive research experience in behavioral ecology and bioacoustics. In addition, the researchers will engage in science education and outreach activities aimed at elementary school children, adults in non-science careers, and members of underrepresented groups in science via hands-on science activities, public appearances, and writing for non-technical audiences.This project examines how the experience of male song quality during development affects female mating behavior in the Pacific field cricket. Male crickets produce song that females use to identify and localize appropriate mates. Within Hawaii, the crickets experience a novel selection pressure against singing preferred songs: an acoustically orienting parasitoid fly that preferentially infests males with the same song characteristics preferred by female crickets. Recently, a mutation arose that makes male crickets obligately silent ('flatwing'). Female crickets strongly prefer singing males, and also have directional preferences about temporal properties of the song. Plasticity in expression of these preferences could facilitate maintenance of this population when available males of preferred phenotypes are few, but this plasticity could have consequences for the strength of selection on sexual signals. Indeed, both males and females reared in silence, mimicking an all-mutant environment, become more phonotactic, suggesting that mating behavior is plastic and selection on signals in nature may be relaxed. In this study, the researchers will rear crickets in acoustic environments that vary by the value of a preferred trait and use phonotaxis trials (females) and song recordings (males) to determine: 1) whether signal production is plastic; 2) whether expression of female mating preferences is plastic; 3) whether population differences in the extent of this plasticity support the hypothesis that plasticity in mating behavior is an adaptive response following the introduction of flatwing.