Title

Sperm precedence in genetically differentiated populations of Drosophila Melanogaster

School Name

South Carolina Governor's School for Science and Mathematics

Grade Level

12th Grade

Presentation Topic

Zoology

Presentation Type

Mentored

Abstract

Sperm precedence is a mechanism in many organisms, including Drosophila melanogaster, by which sperm of one male is more likely to fertilize eggs than sperm of another male. Because the relative fitness of a male will be determined by the success of his sperm in competition with another male, selection can shape competitive interactions between males that occur within the female reproductive tract. While this type of conspecific sperm precedence is well established in different species of Drosophila, it is unclear to what extent this occurs between populations of the same species. In this experiment, we used two genetically differentiated long-term laboratory populations (IV and LHm), to ask two questions: 1) Do males from different genetic backgrounds show differences in reproductive success when mated to females? 2) Do males from different genetic backgrounds show differences in sperm competition outcomes? To answer these questions, we mated IV female and IV male pairs, as well as IV female and LHm male pairs. Some IV females were mated in sequence, first with an IV male, and then with an LHm and vice versa. The average number of offspring produced by females were then compared. Despite it being well established in Drosophila that second males father the majority of offspring (Price 1997), LHm males sired significantly less offspring than their IV counterparts regardless of mating order. While the reason for this reduced reproductive success is not entirely known, this research is important in understanding the process of genetic differentiation and ultimately how speciation occurs.

Location

HSS 107

Start Date

4-2-2022 10:00 AM

Presentation Format

Oral and Written

Group Project

No

COinS
 
Apr 2nd, 10:00 AM

Sperm precedence in genetically differentiated populations of Drosophila Melanogaster

HSS 107

Sperm precedence is a mechanism in many organisms, including Drosophila melanogaster, by which sperm of one male is more likely to fertilize eggs than sperm of another male. Because the relative fitness of a male will be determined by the success of his sperm in competition with another male, selection can shape competitive interactions between males that occur within the female reproductive tract. While this type of conspecific sperm precedence is well established in different species of Drosophila, it is unclear to what extent this occurs between populations of the same species. In this experiment, we used two genetically differentiated long-term laboratory populations (IV and LHm), to ask two questions: 1) Do males from different genetic backgrounds show differences in reproductive success when mated to females? 2) Do males from different genetic backgrounds show differences in sperm competition outcomes? To answer these questions, we mated IV female and IV male pairs, as well as IV female and LHm male pairs. Some IV females were mated in sequence, first with an IV male, and then with an LHm and vice versa. The average number of offspring produced by females were then compared. Despite it being well established in Drosophila that second males father the majority of offspring (Price 1997), LHm males sired significantly less offspring than their IV counterparts regardless of mating order. While the reason for this reduced reproductive success is not entirely known, this research is important in understanding the process of genetic differentiation and ultimately how speciation occurs.