PARENT SESSION
Poster Session 34: Herbivory
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Oak genotype and leaf chemisty effects on cynipid gall-wasp communities.

Inouye, Brian^*,1, ¹ Florida State University, Tallahassee, FL

ABSTRACT- The galls induced on oak trees by wasps in the family Cynipidae are strikingly diverse. There are hundreds of described cynipid species, and individual trees can host tens of cynipid species, along with their associated inquilines and parasitoids. Why some oak species and oak trees have more diverse gall-wasp communities than other oaks is unknown, but previous work has suggested important roles for oak secondary chemistry, phenology, oak phylogenetic patterns, historic patterns of cynipid radiations and host-shifts, parasitoid communities, and local land management regimes (e.g. fires, urban tree management). I have investigated the effects of leaf secondary chemistry and tree genotype on the cynipid gall-wasp community in a 15-year-old common garden of blue oak (Quercus douglasii) in northern California. While seedlings and small saplings are rarely used by gall-wasps, these trees are large enough to have been colonized by at least 21 species of gall-wasps. Gall-wasp densities were significantly affected by the oak source population and changed from year to year, but there was no significant year x source population interaction, indicating that patterns in the gall-wasp community were fairly consistent over three years. Most individual secondary compounds were not correlated or only weakly correlated with gall-wasp communities or abundance, but increasing total foliar nitrogen was significantly correlated with increasing abundance of gall-wasps.

Key words: Quercus, Cynipidae, gall-wasps