Graduate Program

Biological Sciences

Degree Name

Master of Science (MS)

Semester of Degree Completion

2005

Thesis Director

Ann Fritz

Thesis Committee Member

Paul Switzer

Thesis Committee Member

Thomas Nelson

Abstract

Countless numbers of insects have copulatory behaviors performed while in copulation. Copulatory behaviors or copulatory courtship performed by males may be a means to influence female sperm storage patterns. Sexual selection in regards to female processes that influence male reproductive success are termed "cryptic female choice." In my thesis I examined copulatory behaviors performed by mass-reared male Anastrepha suspensa and sperm storage patterns in relation to male behavioral performance in females. I videotaped copulating virgin males and females of different ages and recorded mating duration, size of both sexes, male proboscis extensions, male probing of the females' head, thorax and cervix, and female restlessness. VHS tapes were scored in minute intervals to obtain a quantitative value of each behavior. Females were dissected and the 4 sperm storage organs, which are 3 spermathecae and a ventral receptacle, and the remaining reproductive tract were removed to obtain a quantitative number of sperm passed to each separate organ. The 4 behaviors were found not to be performed equally and there is a chronological order of behaviors performed by males with the majority of the behaviors being performed during the first 10 minutes of copulation. Females were restless during the final stages of copulation, possibly controlling duration length. Males that were young (i.e. 4, 5, 6 days old) in comparison to males that were old (i.e. 19, 20, 21 days old) significantly differed in older males performing more proboscis extensions, and having longer mating durations, demonstrating an age difference. Sperm quantities within the 4 sperm storage organs had the majority of the sperm occurring in the ventral receptacle. Although, the ventral receptacle did not store as much sperm as any single spermathecae, which was extremely variable, thus females use all 4 organs differentially. Old flies mating durations correlated with total sperm quantity. The young couples were found to have male behavioral repertoire related to all 3 spermathecae sperm storage quantities and vagina/bursa. Results presented here suggest A. suspensa are capable of cryptic female choice due to differential sperm storage patterns and differences in male behavioral repertoires. A. suspensa is subject to Sterile Insect Technique, thus this information may be useful to this particular program.

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