EAPSI:Does Sexual Selection Promote Color Diversification in Southeastern Asian Medakas?

Yong Lengxob, Greenville NC

Investigators

Abstract

The Indonesian islands are a remarkable biodiversity hotspot that harbor abundant and colorful species richness. The diversity is attributed to high rates of speciation or species formation, where groups of organisms that adapt to different environments ultimately become unable to interbreed. Yet, the detailed mechanisms leading to speciation in these species are not completely known. Here, the researcher will examine one of these mechanisms, specifically testing whether male elaborate traits in medaka fishes (Oryzias sp.) native to Indonesia have evolved from differences in female preference. The research will also test whether female preference for different male color type might serve as a behavioral isolating mechanism, preventing medaka species from interbreeding in nature. The project will be conducted at Japan?s National Institute of Genetics, with Dr. Jun Kitano, a leading scientific expert on fish speciation who has worked closely with the native fish. Teasing apart the behavioral components by which new species arise is fundamental to understanding the beginning stages of how biodiversity is generated. Demonstrating speciation by sexual selection is still a challenging task in evolutionary biology. The proposed research will tackle this longstanding issue by 1) characterizing in details male body color variation within and between sister-species of medaka species, O. woworae and O. celebensis, using quantitative colorimetric techniques, and 2) testing for variation in female preference for male body coloration using mate choice behavioral experiment conducted under different light environments. The results will offer fundamental insights on how sexually selected male conspicuous traits and female preference can diverge and ultimately lead to the evolution of premating isolation between Indonesian medaka species. This NSF EAPSI award is funded in collaboration with the Japanese Society for the Promotion of Science.