Size me up: Variation in sexual selection on body size in walnut-infesting flies
Grade Level at Time of Presentation
Senior
Major
Animal Behavior and Ethology
Minor
Biology
Institution 25-26
University of Louisville
KY House District #
23
KY Senate District #
9
Faculty Advisor/ Mentor
Sophia C. Anner, Alycia C.R. Lackey
Department
Dept. Biology
Abstract
Sexual selection, or the process that favors traits for acquiring mates, is a powerful evolutionary mechanism that can drive trait variation. Body size is one trait that is commonly under sexual selection, but the target and direction of selection for body size is highly variable across mating systems and taxa. When males compete for females, larger males are typically more successful and there is strong selection for increased male size, such as with elephant seals and stalk eyed flies. In insects, selection often favors increased female size as larger females are able to produce more eggs. We evaluated the potential for sexual selection on body size in Rhagoletis juglandis, a walnut-infesting fly that exhibits both courtship and competition behaviors. We conducted mating trials with one female and two males to assess if females choose a mate based on male body size. Further, we evaluated body size variation in R. juglandis as well as two additional related species (R. completa and R. suavis) to understand how this trait differs between them.These measurements allow us to assess the potential implications for variation in sexual selection and if does body size correlates with reproductive success. By identifying traits that best explain variation in mating behavior, this research contributes to our understanding of evolutionary processes, sheds light on the mechanisms of sexual selection, and may have broader implications for agricultural pest management of this species.
Size me up: Variation in sexual selection on body size in walnut-infesting flies
Sexual selection, or the process that favors traits for acquiring mates, is a powerful evolutionary mechanism that can drive trait variation. Body size is one trait that is commonly under sexual selection, but the target and direction of selection for body size is highly variable across mating systems and taxa. When males compete for females, larger males are typically more successful and there is strong selection for increased male size, such as with elephant seals and stalk eyed flies. In insects, selection often favors increased female size as larger females are able to produce more eggs. We evaluated the potential for sexual selection on body size in Rhagoletis juglandis, a walnut-infesting fly that exhibits both courtship and competition behaviors. We conducted mating trials with one female and two males to assess if females choose a mate based on male body size. Further, we evaluated body size variation in R. juglandis as well as two additional related species (R. completa and R. suavis) to understand how this trait differs between them.These measurements allow us to assess the potential implications for variation in sexual selection and if does body size correlates with reproductive success. By identifying traits that best explain variation in mating behavior, this research contributes to our understanding of evolutionary processes, sheds light on the mechanisms of sexual selection, and may have broader implications for agricultural pest management of this species.