Date of Award

Spring 2014

Document Type

Restricted Thesis

Terms of Use

© 2014 Cristian C. Taborda. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts



First Advisor

Kathleen King Siwicki

Second Advisor

Alexander T. Baugh


Compared to the wealth of information available on male courtship behavior in Drosophila melanogaster, we know relatively little about female sexual behavior. The female's role during courtship has been historically relegated to "acceptance" or "rejection", often ignoring any of her precopulatory behaviors. In this study, I investigated three female precopulatory behaviors—ovipositor extrusion, immobility, and grooming—that potentially communicate information about her receptivity and modulate male behavior. Using high-resolution video recording, I (1) measured these behaviors at three different levels of male exposure, (2) measured female behavior before and after her own ovipositor extrusion, and (3) analyzed male behavior preceding and following ovipositor extrusion. In addition, I compared these behaviors between virgin and mated females. I report that ovipositor extrusion and immobility were sensitive to male presence. Specifically, both virgins and mated females extruded their ovipositor at a high rate during male contact, but performed no extrusions with no access or limited sensory access to a male. Only virgins increased immobility during male contact, while mated females maintained baseline locomotive activity at all levels of male exposure. Next, I report no difference in either the rate of ovipositor extrusion or the context in which the extrusion occurred between virgins and mated females. Although ovipositor extrusion did not immediately change the amount of male courtship, it did change the type of courtship behaviors that males expressed. Principally, males shifted from non-contact courtship behaviors to contact-mediated courtship behaviors immediately following ovipositor extrusion from both types of females. These results suggest that females are playing an active role during courtship.