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Divergent Mating Behaviors and the Evolution of Reproductive Isolation

Yang, Yu-San (2020) Divergent Mating Behaviors and the Evolution of Reproductive Isolation. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Sexual selection can cause rapid co-divergence of mating traits and mate preferences, generate reproductive barriers among individuals bearing divergent mating traits, and potentially lead to speciation. In my dissertation, I focused on two emerging topics that challenge this traditional speciation-by-mate-choice paradigm. First, sexual selection encompasses both mate preferences and intrasexual competition, yet speciation research disproportionally focused on the role of the former. Second, sexual behaviors are usually assumed to be genetically inherited, but they may often be shaped by learning instead, which can generate very different evolutionary trajectories for traits and preferences. Using studies of the highly polymorphic strawberry poison frogs (<i>Oophaga pumilio</i>), I demonstrated how incorporating (i) male-male competition and (ii) behavioral learning can enhance our understanding of the potential for speciation to be driven by sexual selection. I first characterized behavioral patterns across a natural contact zone between color morphs and showed that coloration (the divergent mating trait) mediates both female choice and male-male competition. Females often prefer males of their own (local) color over a novel color, and males, when defending territories, are more aggressive against their own color morph. I then tested how these color-mediated female preferences and male aggression biases interact to determine mating patterns. I conducted a controlled breeding experiment in which male-male competition and female mate choice act either in same or in opposing directions. In this study, females reproduced more often with the territorial male over the non-territorial male, regardless of the males’ coloration. This challenges the common assumption that knowledge of female preferences for male mating traits is sufficient to predict mating patterns. Finally, I discovered that learning from mothers during the tadpole stage shapes both female mate preferences and male aggression biases in <i>O. pumilio</i>. Based on this finding, I built a population genetic model and used it to demonstrate a simple and elegant mechanism by which sexual selection alone has the potential to initiate speciation. My research highlights the importance of considering interactions between mate choice, intrasexual competition, and behavioral learning, for studies of mating trait evolution and sexual selection’s role in speciation.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Yang, Yu-Sanyusan.yang@pitt.eduyuy580000-0003-2765-4197
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairRichards-Zawacki, Corinne L.cori.zawacki@pitt.edu0000-0002-4212-041X
Committee MemberCarson, Walter P.walt@pitt.edu0000-0001-7246-3790
Committee MemberRebeiz, Markrebeiz@pitt.edu0000-0001-5731-5570
Committee MemberTurcotte, Martin M.turcotte@pitt.edu0000-0003-3949-6958
Committee MemberServedio, Maria R.servedio@email.unc.edu0000-0002-3965-4445
Date: 16 September 2020
Date Type: Publication
Defense Date: 29 April 2020
Approval Date: 16 September 2020
Submission Date: 14 April 2020
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 131
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Biological Sciences
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Sexual Selection, Animal Behavior, Evolution, Speciation, Learning, Imprinting, Mate Choice, Male-Male competition, Territoriality, Coloration, Population Divergence, Reproductive Isolation, Poison Frog, Color polymorphism
Date Deposited: 16 Sep 2020 15:32
Last Modified: 16 Sep 2020 15:32


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