Figure 1.
Resource availability and trait variation in oak cynipid galls.
(A) Gallwasp larvae. 1. A gallwasp larva (Andricus lucidus asexual generation) in its larval chamber. 2. Multiple larvae in the multilocular sexual generation gall of Biorhiza pallida. (B) One of the parasitoids in this study, M. stigmatizans (Torymidae) drilling through the wall of an oak cynipid gall. (C) Matrix showing some of the diversity in defensive gall morphologies [23] and gall locations represented by species in this study, with examples (sg, sexual generation; ag, asexual generation): 1. A. lucidus (ag). 2. A. hartigi (ag). 3. A. grossulariae (ag). 4. A. caputmedusae (ag). 5. A. lignicolus (ag). 6. A. gemmeus (ag). 7. A. lucidus (sg). 8. Cynips longiventris (ag). 9. Callirhytis glandium (ag). 10. Dryocosmus nitidus (sg). 11. Neuroterus lanuginosus. 12. A. quercustozae (ag). 13. A. grossulariae (sg). 14. A. quercuscalicis (ag). 15. A. coronatus (ag). Scale bar = 5 mm in all images.
Table 1.
Summary of host characters used as explanatory variables in analyses of parasitoid community composition.
Figure 2.
Phylogenetic relationships between host gallwasps.
The mitochondrial DNA sequence phylogeny of host gallwasps, presented as a cladogram with node support shown by posterior probabilities in Bayesian analyses (see Materials and Methods). Coloured symbols at branch tips indicate gallwasp clade membership (following 23,25,39), allowing recognition of phylogenetic patterns in Figure 3. The shape of the symbol indicates the generation included in our analysis (circle, asexual; square, sexual).
Figure 3.
Cluster analyses showing similarity in parasitoid community composition and gall phenotypes.
Cluster analyses showing similarities between gall types in (A) parasitoid assemblage composition, and (B) spatiotemporal niche character states (see Materials and Methods). Colours of symbols at branch tips match those for the clades in Figure 2. Sexual generation galls are indicated by square symbols and red branches.
Table 2.
Phylogenetic patterns in host gall traits and parasitoid communities for sexual and asexual gallwasp generations.
Table 3.
Significant matrix correlations between gall traits (rows) and Bray-Curtis similarity in parasitoid assemblage composition.
Table 4.
Parameter estimates, significance, and percent deviance explained in MAMs for PRAs of parasitoid community composition (see Materials and Methods).
Figure 4.
Host trait-associated variation in parasitism by generalist parasitoids in communities associated with sexual and asexual generation oak gallwasp communities.
The dominance plot shows, for the five most generalist parasitoid species, the proportion individuals of a given species comprise of all emerged parasitoids ( = dominance) averaged across host gall types with specific gall locations and oak associations. Gall locations refer to the plant organ galled (the location category “wood” refers to galls integral to the main axis of shoots), while oak taxon associations refer to gall induction on species in either Quercus section Cerris or section Quercus sensu stricto. The selected parasitoid taxa are A. gallarum (Eulophidae), C. fungosa (Pteromalidae), E. brunniventris (Eurytomidae), M. dorsalis (Torymidae), and S. biguttata (Eurytomidae). The data from different host gall types have been pooled at two biologically relevant spatial scales, namely galls on different plant organs (left) and on different oak host taxa (right).