Mindy Reutter
Dr. Greg Davis
Biology

Measuring Whole-body, Hemolymph and Embryonic Juvenile Hormone Titers in the Pea Aphid

The cyclically parthenogenetic life cycle of the pea aphid Acyrthosiphon pisum involves both sexual and asexual reproduction. The reproductive mode of offspring is determined during embryogenesis within the mother. Previous research correlates long photoperiod (short nights) to high Juvenile Hormone (JH) titers and implicates the level of JH titer experienced by the embryo as the signal that determines whether it becomes sexual or asexual. It is unknown whether it is embryonic or maternal JH that is ultimately responsible for determining the embryo's reproductive fate. Our project aims to quantify maternal JH titers when mothers are producing sexual and asexual progeny, and to quantify embryonic JH titers in sexual and asexual fated embryos. The goal is to identify which sources of JH (maternal or embryonic or both) are correlated with changes in reproductive fate. To do this we will collect JH samples from both mothers and embryos exposed to varying photoperiod conditions. We will send these samples to Dr. Fernando Noriega, our collaborator at Florida International University, for quantitative analysis. Knowing which source of JH is responsible for the shift between reproductive fates will help us to focus our later studies on evolved changes in the response to photoperiod, which we believe to be due to changes in JH sensitivity.