Meeting Abstract

P1.2  Sunday, Jan. 4  A "Silver Ovipositor" Effect in the Walnut Fly, Rhagoletis juglandis. DAVIS, J.M.*; PAPAJ, D.R.; Vassar College; University of Arizona jedavis@vassar.edu

Variation in the quality of habitats can result in variation in the physiological and morphological traits of animals that develop within them. One potential consequence of this is that the phenotypes of animals from high quality habitats may provide them advantages when it comes to finding, defending and/or utilizing similarly high quality habitats. Such "Silver Spoon" effects can have important population consequences, but are rarely tested for. Here, we test for a silver spoon effect in the walnut fly, Rhagoletis juglandis. Previous research has demonstrated that the size of this fly is negatively influenced by the number of larval competitors inhabiting the fruit in which it develops. However, while unused fruit provides the best larval environment, it can be difficult for females to penetrate unused walnut husks and females are frequently observed re-using sites where eggs have previously been laid. We tested whether larger females have an advantage in penetrating surfaces with their ovipositors, thus providing them more opportunities to put their offspring in unused fruit. We demonstrated that larger females are more able to penetrate fruit models, and as a consequence lay more eggs per minute, but fewer eggs per oviposition bout. Such a pattern indicates that some of the variation in size and fecundity seen in this species may be non-genetically inherited via a host-mediated maternal effect.