DISSERTATION RESEARCH: Evolutionary dynamics of female polymorphism: an invasive damselfly model

University Of Texas At Austin, Austin TX

Investigators

Abstract

Female coloration is highly variable within many animal species. What maintains this diversity, and how can it inform our general understanding of evolution? While theory suggests that both sexual and natural selection might diversify female color, the role(s) of these mechanisms in female evolution have not been jointly tested within a single study system. Invasive populations of a damselfly, Ischnura ramburii provide unique opportunities to close this gap. Frequencies of I. ramburii female color morphs have changed dramatically since the colonization of Hawaii. Today, the frequencies of ?andromorph? females, which visually resemble males, are correlated with both invasive population densities and rainfall. Using experimental mesocosms constructed within invaded sites, the investigators will examine how male-female interactions and color morph performance (survival and fecundity) are influenced by morph frequency, by population density, and by the abiotic environment (rainfall). Outcomes will be used to determine how social and physical environments drive female color evolution, and to identify conditions that promote female diversity. In addition to identifying factors that maintain female variation in nature, the study will shed new light on how invasive populations evolve, suggesting novel strategies for mitigating invasions. Proposed work will provide unique research opportunities for several undergraduates, and findings will be shared with the public via the media, and through a series of highly successful outreach talks that the investigators co-founded in 2008.