Throughout 2008,
galls were checked every other month, and the survey was terminated in January 2009. Galls from which nothing had emerged over the course of the study (n = 257) were removed from further analysis in order to minimize the effects of mortality due to experimental conditions (premature removal from the tree or subsequent fungal infection). Insects were first grouped into morphospecies. Species identifications were then acquired for most morphospecies, and voucher specimens were deposited at the UC Davis, Bohart Museum of Entomology. Functional groups (whether the insect was a parasitoid, inquiline, or facultative gall occupant) of the selleck screening library P505-15 most common species were determined by rearing the insects and determining where their larvae developed by repeated cross-sectioning of the galls from which they had emerged. For each of the 7 most abundant gall-occupants, galls from which only the focal insect species had emerged were chosen. The galls were then cut into 7.5 mm cross-sections using a band-saw, and the emergence tunnel was traced back to the larval chamber of the gall-occupant. If emergence tunnels led to the central growth chamber
of A. quercuscalifornicus (which is recognizable by its connection to the plant vasculature), but no A. quercuscalifornicus had emerged from that chamber, then the insect in question was considered a parasitoid of A. quercuscalifornicus. Nintedanib (BIBF 1120) If emergence tunnels led to the gall tissue away from an A. quercuscalifornicus chamber, then the insect was considered an inquiline. For each functional group determination, multiple galls were cross-sectioned to confirm our categorizations. This method could distinguish between parasites of the gall inducer and parasites of
its inquilines, but it could not detect interactions between parasites, such as hyperparasitism. Phenologies of the six most common gall associates were constructed using bi-monthly intervals for the intensive sampling time period (July–Dec. 2007), and at 6 month intervals for the less frequently sampled period (Jan.–Dec. 2008). For each of these six species, the numbers of adults emerging were summed over all galls and plotted against time. Gall size measures and statistical analyses Gall volume was measured using water displacement. We analyzed the association of insect species with gall traits first using only presence/absence of each insect species and using abundance GDC-0449 purchase information. To investigate patterns of host-use by the six most common insects emerging from oak apple galls, we used logistic regression where gall volume, maturation date (Julian date collected), and locality predicted the occurrence of a given species.