Research

My research focuses on how the interplay of natural and sexual selection influences diversification, especially of traits related to mating. Sexual traits are often the most elaborate and flamboyant aspects of biodiversity, and critical for successful reproduction and maintenance or generation of species. The classic paradigm is that natural and sexual selection act in opposite directions — that sexual selection favors trait elaboration while natural selection favors trait reduction. While this can certainly be the case, evolution of sexual traits is rarely this simple in the wild. My research takes an integrative approach that incorporates multiple aspects of ecology, sexual selection, social dynamics, plasticity and physiology to test hypotheses about the causes and consequences of sexual trait diversification.

For my postdoctoral research, I use Pacific field crickets (Teleogryllus oceanicus) to investigate the consequences of rapid sexual signal loss. In Hawaii, many male crickets have recently lost the ability to produce the acoustic sexual signal that females find attractive due to strong selection from a deadly parasitoid fly that used the same male song to find its cricket host. In this new environment that is mostly devoid of song, its unclear how female crickets find and evaluate mates. I am looking at how plastic and genetic effects of the silencing mutation influence a range of behaviors, phenotypic traits, and fitness. This work sheds light on what influences whether populations persist or face extinction in the face of a major shift to the mating system.

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Pacific field cricket (T. oceanicus) in the wild. Photo credit: Rachel Olzer

Field Work 15

Catching crickets during fieldwork on the Big Island of Hawaii. Photo credit: Rachel Olzer

My PhD work used Bahamian mosquitofish (Gambusia spp) to test how predictably differences in predation risk promotes divergence between populations, both directly via natural selection and indirectly by altering sexual selection. I mostly focused on mosquitofish living in blue holes across Andros Island, which provide a great natural experiment to isolate the effects of predation because many isolated mosquitofish populations exist that differ most dramatically in the presence / absence of predatory fish for the last ~10k years. I also studied mosquitofish inhabiting tidal creeks across the Bahamian islands where some populations have recently been fragmented by human activities, resulting in a suite of ecological differences between fragmented and unfragmented sites. My dissertation teased apart the relative importance of multiple ecological factors on diversification of colorful visual signals, male genital morphology, behaviors (e.g., sexual, social, foraging, exploratory, aggressive), and population dynamics.

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Two male mosquitofish (G. hubbsi) swimming in a blue hole. Photo credit: Brian Langerhans

me taking data with a pretty scene

Preparing for mosquitofish fieldwork at a blue hole on Andros Island.

 

 

 

 

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