Diversity, abundance and community network structure in sporocarp-associated beetle communities of the central Appalachian Mountains

Abstract

Although arthropods are abundant and diverse in and on macrofungal sporocarps, their associations with fungi seldom have been described at a community level. We examined sporocarp-associated beetle communities in two primary sites in the Appalachian Mountains and foothills, assessing beetle diversity and abundance in relation to study site, sampling season (early vs. late summer), and sporocarp characteristics such as taxonomic position, dry mass and age. From 758 sporocarps representing >180 species we recovered 15 404 adult beetles representing 72 species and 15 families, primarily Staphylinidae (> 98% of individuals and of 64% morphospecies). The probability of sporocarp colonization by beetles, beetle abundance and diversity differed among fungal species and were positively associated with sporocarp dry mass. Sporocarp age was positively correlated with beetle diversity and abundance (as measured in a focal species, Megacollybia platyphylla, Tricholomataceae), and its effects were independent of dry mass. Many beetle species were generalists, visiting a wide breadth of fungi in both the Agaricales and Polyporales; however, several beetle taxa showed evidence of specialization on particular fungal hosts. Host association data were used to examine the structure underlying sporocarp-beetle associations. Here we present the first evidence of nested community structure in the sporocarp-beetle interaction network.

• Coleoptera
• ephemeral resource
• Erotylidae
• Gyrophaenina
• host specificity
• interaction web
• Megacollybia platyphylla
• mycophagy
• Staphylinidae

We thank Alex Lovinger for assistance in counting and sorting insects, Carl Olson, Kojun Kanda and Vassili Belov for help with beetle identification, Taro Eldredge and Adam Brunke for assistance with staphylinid identification, Stewart Peck for determination of Colenis impunctata and Kipling Will for determination of our carabid specimen. We thank Jana U’Ren for statistical advice and suggestions regarding data representation, Martina Stang and Ruben Alarcon for discussion of ecological networks, members of the Arnold lab for helpful discussion, Tom Bruns and Brian McGill for guidance, and Michele Lanan, Judie Bronstein, David Maddison, and Robert Steidl for insights and comments on the manuscript. Mountain Lake Biological Station (University of Virginia) provided financial support, laboratory facilities and research space for this work. We thank the Department of Ecology and Evolutionary Biology, the College of Agriculture and Life Sciences, and the Robert L. Gilbertson Mycological Herbarium (ARIZ) at the University of Arizona for additional financial support.