How the Morphology of the Proboscis of Monarch Butterflies (Danaus plexippus) is Affected by the Season in which They Hatch

Abstract

By Daniel Mounir, Biological Sciences

Advisor: Patrick Guerra

Presentation ID: 153

Abstract: In the different seasons, the monarch butterfly emerges from its chrysalis, but the way a monarch butterfly feeds is always the same. Monarchs use their proboscis to drink nectar from flowers to obtain the sugars and nutrients that they need. The proboscis is two halves of a tube held together by the saliva of the butterfly, in order to make a full tube. In this study, preserved monarchs collected from either the summer or fall were soaked in water for two hours to loosen the proboscis, in order to develop a practical technique for proboscis measurement. After extending each proboscis using pins and staples, they were left to re-harden over several days. Pictures of each proboscis were then captured using the digital camera of a dissecting microscope. ImageJ measuring software was used to make measurements of each proboscis for quantitative comparisons between butterflies of the different groups. We hypothesized that the proboscises of summer butterflies will be longer than those of their fall counterparts due to differences in available flowers in the summer relative to during the fall. No results have been found yet for the project, but our imaging and measurement approach appears to be feasible for testing our hypothesis.