MALE AND FEMALE REPRODUCTIVE ROLES IN THE CONTEXT OF LIFE HISTORY AND NUTRITIONAL ECOLOGY.
Tigreros, Natasha.
2017-04-24T15:11:45.420Z
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Abstract: Charles Darwin characterized sex roles as males pursuing and competing to gain females attention, and females acting coy and choosy in selecting their mates. Since then, the idea of "typical sex roles" has been a cornerstone for much of sexual selection theory. However, the last forty years have seen numerous studies showing that females in many species actively solicit multiple matings,... read moreand that males can be prudent and even picky when choosing a mate. Understanding the causes and consequences of these "non- typical" sex roles is an important part of contemporary biology. This dissertation uses a framework that incorporates testing adaptive and non-adaptive hypotheses to improve our knowledge of how non-typical male and female sexual traits and behaviors evolve. The first part of this dissertation focuses on explaining sexual traits and behaviors in Pieris rapae butterflies, a species whose mating system includes nuptial gifts. My studies indicate that production of nuptial gifts by males, and acquisition of nuptial gifts by females are important drivers of non-typical sexual traits and behaviors. First, limitation of dietary nitrogen decreased female but not male allocation to primary reproduction. Low-nitrogen males sacrificed wing coloration, a trait associated with their mating success. P. rapae males might maximize fitness by protecting their investment in nuptial gifts and carefully choosing a mate. Supporting this idea I showed that males preferred to mate with more fecund females that had been reared in high-nitrogen diets. My studies also indicated that male mate choice drives exaggeration of female coloration, a trait that honestly signals female fecundity in P. rapae. Using an individual based simulation and knowledge based on lepidopteran biology, I demonstrated that male gifts can determine the magnitude of benefits that females obtain from allocating resources to ornaments. These simulations showed that females obtained maximum benefit by allocating almost half of their reproductive resources to ornaments and by acquiring multiple gifts. In the last study presented in this dissertation, I used Tribolium castaneum flour beetles and applied sexually antagonistic selection on body size, which is an important trait for both male and female reproduction. My results showed that between-sex genetic correlations constrained the independent evolution of body size. These results support the idea that certain traits and behaviors, such as body size and ornamentation, can evolve as a correlated response to selection on the other sex.
Thesis (Ph.D.)--Tufts University, 2013.
Submitted to the Dept. of Biology.
Advisor: Sara Lewis.
Committee: Frances Chew, Michael Reed, Colin Orians, Jan Pechenik, and Philip Starks.
Keywords: Evolution & development, Ecology, and Behavioral sciences.read less - ID:
- js956s62j
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