title: Vertical stratification of ichneumonid wasp communities: the effects of forest structure and life-history traits.
abstract: Parasitoid wasp communities of the canopy of temperate forests are still largely unexplored. Very little is known about the community composition of parasitoids between canopy and understory and how much of this difference is related to forest structure or parasitoid biological strategies. In this study we investigated upon the difference in the community composition of the parasitic wasps Ichneumonidae between canopy and understory in a lowland temperate forest in northern Italy. We used general linear models to test whether parasitic strategy modifies species vertical stratification and the effect of forest structure. We also tested differences in β-diversity between canopy and understory traps and over time within single forest layers. We found that stand basal area was positively related to species richness, suggesting that the presence of mature trees can influence local wasp diversity, providing a higher number of microhabitats and hosts. The ichneumonid community of the canopy was different from that of the understory, and the β-diversity analysis showed higher values for the canopy, due to a higher degree of species turnover between traps. In our analyses, the vertical stratification was different between groups of ichneumonids sharing different parasitic strategies. Idiobiont parasitoids of weakly or deeply concealed hosts were more diverse in the understory than in the canopy while parasitoids of spiders were equally distributed between the two layers. Even though the ichneumonid community was not particularly species-rich in the canopy of the temperate forests, the extension of sampling to that habitat significantly increased the number of species recorded.
authors.affiliation: Dipartimento di Biologia e Biotecnologie "Charles Darwin", Università di Roma "La Sapienza", Piazzale A. Moro 5, 00185, Rome, Italy.|Centro Nazionale per lo Studio e la Conservazione della Biodiversità Forestale, Corpo Forestale dello Stato, via Carlo Ederle 16/A, 37100, Verona, Italy.|DAFNAE, Università di Padova, viale dell'Università 16, 35020, Legnaro, Padua, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Di Giovanni
authors.affiliation: Dipartimento di Biologia e Biotecnologie "Charles Darwin", Università di Roma "La Sapienza", Piazzale A. Moro 5, 00185, Rome, Italy.|Centro Nazionale per lo Studio e la Conservazione della Biodiversità Forestale, Corpo Forestale dello Stato, via Carlo Ederle 16/A, 37100, Verona, Italy.|DAFNAE, Università di Padova, viale dell'Università 16, 35020, Legnaro, Padua, Italy.
authors.forename: Pierfilippo
authors.initials: P
authors.lastname: Cerretti
authors.affiliation: Centro Nazionale per lo Studio e la Conservazione della Biodiversità Forestale, Corpo Forestale dello Stato, via Carlo Ederle 16/A, 37100, Verona, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Mason
authors.affiliation: Centro Nazionale per lo Studio e la Conservazione della Biodiversità Forestale, Corpo Forestale dello Stato, via Carlo Ederle 16/A, 37100, Verona, Italy.
authors.forename: Emma
authors.initials: E
authors.lastname: Minari
authors.affiliation: DAFNAE, Università di Padova, viale dell'Università 16, 35020, Legnaro, Padua, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Marini
mesh_terms: D000818:Animals; D001181:Arthropods / Q000469:parasitology; D044822:Biodiversity; D017753:Ecosystem; D065928:Forests; D007558:Italy; D014197:Trees; D014863:Wasps / Q000145:classification / Q000502:physiology*
keywords: Ichneumonidae; biological traits; canopy; forest structure; vertical stratification; β-diversity