Graduate Program

Biological Sciences

Degree Name

Master of Science (MS)

Semester of Degree Completion

Winter 2018

Thesis Director

Ann Fritz

Thesis Committee Member

Gary Fritz

Thesis Committee Member

Zhiwei Liu


Anastrepha suspensa (Diptera; Tephritidae) is an agricultural pest species

causing severe economic damage and is controlled, in part, by applying knowledge

of this species' reproduction (e.g., disrupting fertile copulations by SIT). During

copulation, males transfer sperm as well as protein rich fluids through an aedeagus

and distiphallus, which females then store in three spermathecae and one ventral

receptacle. Within the female reproductive tract, the ventral receptacle and the

three spermathecae are strategically separated from each other. I hypothesized

males' ability to direct sperm transfer within the female reproductive tract is

through the structures found in the distiphallus. Utilizing scanning electron

microscopy, fluorescent light microscopy and light microscopy, coupled pairs were

dissected and their genitalic positions relative to each other's structures,specifically

the position of the distiphallus during copulation, was deduced. Bifurcation of the

sperm ducts within the distiphallus were observed, suggesting males possess the

ability to direct sperm toward the sperm storing structures. Changes in female

intergenitalic distances was found to correspond to findings on female sperm

storage previously reported. However, through analysis of the distiphallus position

during copulation, the ability for females to control the length of their reproductive

tract was discovered, which suggests that a thorough and detailed understanding

of the morphology of the male genitalia in relation to the morphology of the female

reproductive tract may illuminate the important role of co-evolution between the