Zoology Department Seminar: Rapid evolution in silence: adaptive signal loss in the Pacific field cricket

Our Departmental Seminars run weekly on Thursdays during term time. They cover recent research on a wide variety of topics from evolutionary genetics through behavioural ecology to ecology and natural history.  Please click here for a list of all of this term's seminars.

Everyone in Zoology is invited, and Part II undergraduate zoologists are particularly encouraged to attend. 

Speaker:  Professor Marlene Zuk, Regents Professor Emerita, Department of Ecology, Evolution and Behavior, University of Minnesota

Title: Rapid evolution in silence: adaptive signal loss in the Pacific field cricket

Abstract: 

By nature of their conspicuousness, sexual signals can cause a conflict between natural and sexual selection, with natural selection favoring a decrease in exaggeration of an ornament and sexual selection favoring an increase. 

The Pacific field cricket, Teleogryllus oceanicus, is subject to an acoustically-orienting parasitoid fly where it has been introduced in Hawaii, making calling particularly risky. A novel obligately silent male morph, controlled by a single sex-linked gene, evolved within just 20 generations in some populations in Hawaii. These flatwings are protected from parasitism, but face difficulties in mate attraction and courtship. Pre-existing behavioral plasticity may have facilitated the novel morph’s establishment, along with pleiotropic effects of the gene responsible. 

Recently, even more variants have been discovered in Hawaii, leading to an interest in phenotypic integration and the way that morphology, behavior and fitness contribute to sexual signal divergence.