Host niches and defensive extended phenotypes structure parasitoid wasp communities.

Oak galls are spectacular extended phenotypes of gallwasp genes in host oak tissues and have evolved complex morphologies that serve, in part, to exclude parasitoid natural enemies.Parasitoids and their insect herbivore hosts have coevolved to produce diverse communities comprising about a third of all animal species. The factors structuring these communities, however, remain poorly understood. An emerging theme in community ecology is the need to consider the effects of host traits, shaped by both natural selection and phylogenetic history, on associated communities of natural enemies. Here we examine the impact of host traits and phylogenetic relatedness on 48 ecologically closed and species-rich communities of parasitoids attacking gall-inducing wasps on oaks. Gallwasps induce the development of spectacular and structurally complex galls whose species- and generation-specific morphologies are the extended phenotypes of gallwasp genes. All the associated natural enemies attack their concealed hosts through gall tissues, and several structural gall traits have been shown to enhance defence against parasitoid attack. Here we explore the significance of these and other host traits in predicting variation in parasitoid community structure across gallwasp species. In particular, we test the "Enemy Hypothesis," which predicts that galls with similar morphology will exclude similar sets of parasitoids and therefore have similar parasitoid communities. Having controlled for phylogenetic patterning in host traits and communities, we found significant correlations between parasitoid community structure and several gall structural traits (toughness, hairiness, stickiness), supporting the Enemy Hypothesis. Parasitoid community structure was also consistently predicted by components of the hosts' spatiotemporal niche, particularly host oak taxonomy and gall location (e.g., leaf versus bud versus seed). The combined explanatory power of structural and spatiotemporal traits on community structure can be high, reaching 62% in one analysis. The observed patterns derive mainly from partial niche specialisation of highly generalist parasitoids with broad host ranges (>20 hosts), rather than strict separation of enemies with narrower host ranges, and so may contribute to maintenance of the richness of generalist parasitoids in gallwasp communities. Though evolutionary escape from parasitoids might most effectively be achieved via changes in host oak taxon, extreme conservatism in this trait for gallwasps suggests that selection is more likely to have acted on gall morphology and location. Any escape from parasitoids associated with evolutionary shifts in these traits has probably only been transient, however, due to subsequent recruitment of parasitoid species already attacking other host galls with similar trait combinations.

Review of Anaphes Haliday (Hymenoptera: Mymaridae) with key to species in Europe and a world catalogue.

The Walter Soyka species of Anaphes Haliday are reviewed and placed in context among the remaining world species. An analysis of his descriptions and identification keys is presented, and discussed in light of a broader interpretation of intraspecific variation in Anaphes species than Soyka accepted. An illustrated diagnosis of Anaphes is given and the species in Europe considered to be valid are keyed-14 species in Anaphes (Anaphes) and 15 species in Anaphes (Patasson). The 244 names of world Anaphes are tabulated in various ways and their type localities, if known, are mapped. All available valid names and their synonyms, mostly from among the 155 nominal species described by Soyka, are catalogued, with details of type material and collecting information. A total of 167 synonyms are listed, 17 of which are synonyms proposed by earlier authors and 149 of which are proposed as new synonyms. Lectotypes are designated for Mymar ferreirei Soyka and Yungaburra acutiventris Soyka. Nine nomina dubia, 2 names of fossil species that most likely do not belong to Anaphes, 3 unavailable names and 20 species transferred to other genera are listed separately; among the latter, Anagrus foersteri (Ratzeburg) is transferred to Erythmelus Enock as E. foersteri (Ratzeburg), comb. n. Host records published from 1985-2015 are tabulated; most are from the literature but a few are from unpublished records found on slide mounted Anaphes specimens in various collections, mostly in Europe. The merits of classifying the available names of nominal species into an earlier classification with subgenera Anaphes (Anaphes) and Anaphes (Patasson) instead a later classification consisting of species groups within Anaphes (Anaphes) and Anaphes (Yungaburra) are discussed; the earlier classification is preferred.