Meeting Abstract

P3.95  Monday, Jan. 6 15:30  Induction of reproductive fate in the Pea Aphid SPICA, E.; DAVIS, G.K.*; Bryn Mawr College; Bryn Mawr College gdavis@brynmawr.edu

The pea aphid, Acyrthosiphon pisum, exhibits several environmentally cued, discrete, alternate phenotypes (polyphenisms) during its life cycle. In the case of the reproductive polyphenism, differences in day length determine whether mothers will produce daughters that reproduce either sexually by laying fertilized eggs (oviparous sexual reproduction), or asexually by allowing oocytes to complete embryogenesis within the mother without fertilization (viviparous parthenogenesis). Among other aspects of the polyphenism, we are interested in the process that specifies sexual versus asexual fate during embryonic development. Several lines of evidence implicate juvenile hormone (JH) in this process, namely that titers of JH correlate with day length (1) and that topical application of JH can alter reproductive fate (2). Together these observations suggest that high titers of JH are responsible for specifying asexual fate. We are exploring this JH hypothesis further by testing whether JH is also required for the specification of asexual fate during embryonic development. So far we have confirmed the requirement for JH and hope to extend this result by additionally discriminating among competing models for the role JH plays in the process. (1) Corbit TS, Hardie J. 1985. Juvenile hormone effects on polymorphism in the pea aphid, Acyrthosiphon pisum. Entomologia Experimentalis et Applicata 38: 131-135. (2) Ishikawa A, Ogawa K, Gotoh H, Walsh TK, Tagu D, Brisson JA, Rispe C, Jaubert-Possamai S, Kanbe T, Tsubota T, Shiotsuki T, Miura T. 2012. Juvenile hormone titre and related gene expression during the change of reproductive modes in the pea aphid. Insect Mol Biol 21: 49-60.