Reinforcement and cascade reinforcement in the lucania system: the effects of experimental design, sex, and heterospecific pairings on mate preference
Reinforcement and cascade reinforcement are potentially very potent evolutionary forces (Butlin 1987; Servedio and Noor 2003; Fuller 2016; Pfennig 2016). Their pervasiveness in nature, however, can only be determined through documentation. Currently, the only way to document these processes is to compare levels of reproductive isolation between areas of sympatry and allopatry (Servedio and Noor 2003; Hoskin and Higgie 2010; Pfennig 2016). This often involves using behavioral assays and metrics to determine conspecific or native mate preference in the laboratory. Despite the importance of using assays and metrics that correctly detect reproductive isolation, studies often do not test whether their experimental design accurately measures mate preference. Here, I aimed to determine the best way to measure reproductive isolation using the Lucania (Lucania goodei and Lucania parva) system as a model organism. In my first experiment, I tested multiple assays and metrics of behavior to determine which most accurately measured conspecific and native mate preference for male and female L. goodei. I found that measurements of mating behaviors (i.e. egg production and courting behavior) reliably detected mate preference for male and female L. goodei, while measurements of association time failed to do the same. I also found that only female L. goodei exhibited native mate preference. In my second experiment, I investigated whether previous estimates of reproductive isolation inflated sympatric estimates due to their limited heterospecific pairings. I found that reproductive isolation in male sympatric L. parva is far weaker than previously estimated. Ultimately, I highlight the importance of: using appropriate behavioral assays and metrics to determine reproductive isolation, using both sympatric and allopatric heterospecific stimulus mates when determining levels of reproductive isolation, and measuring reproductive isolation in both sexes.
Evolution, Behavior, Reproductive isolation, Pre-zygotic isolation, Behavioral isolation, Speciation, Experimental design
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign