Taxonomic and behavioral composition of an island fauna: A survey of bees (Hymenoptera: Apoidea: Anthophila) on Martha’s Vineyard (Dukes County, Massachusetts, USA)

Authors: Goldstein, Paul; ASCHER, J. - National University Of Singapore

Submitted to: Proceedings of the Entomological Society of Washington
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2015
Publication Date: 3/1/2016
Citation: Goldstein, P.Z., Ascher, J.S. 2016. Taxonomic and behavioral composition of an island fauna: A survey of bees (Hymenoptera: Apoidea: Anthophila) on Martha’s Vineyard (Dukes County, Massachusetts, USA). Proceedings of the Entomological Society of Washington. 118(1):37-92.

Interpretive Summary: We present the results of an intensive survey of native bees conducted over a two-year period on one of the largest of the region’s offshore islands whose agricultural acreage has shrunk during the 20th century but which is known to support a diverse assemblage of insects unknown from elsewhere in New England. Although our understanding of the more than 3500 described bee species found in America North of Mexico is improving following recent taxonomic revisions and regional inventory efforts, few sampling endeavors adequate to the task of capturing information on specialist bees faunas. Faunal surveys of discrete areas and sites known to serve as refugia for other, well-studied groups of invertebrates are particularly relevant. We summarize and interpret over 14,000 databased records of bees sampled during the course of our work, comprising 185 species; these include the first state and regional records of several species and the first documented population of species of Digger Bee east of Ohio since the 1970s. Our data also suggest that the disappearance of at least two species of bumblebees, believed to be the result of an introduced pathogen, is not confined to mainland New England and that the behavioral and feeding habits of bees may impact the facility with which they can be sampled. The present work complements ongoing studies of native bee faunas elsewhere in the northeastern U.S. and Maritime Canada. The records we report have been added to the growing database of georeferenced specimen records of bees and other relevant pollinator occurrences mapped by Discover Life (www.discoverlife.org) and from there to the Encyclopedia of Life (www.eol.org). The data are also being used in ongoing comparative faunistic research and have already been incorporated in regional status assessments of bees and their response to climate change. Specimens, including those of undescribed species, are deposited at public research institutions where they are available for taxonomic research, and a synoptic collection has been made available locally (to educators, students, and biologists with identification needs).

Technical Abstract: An intensive survey of bees (Hymenoptera: Apoidea: Anthophila) on Martha’s Vineyard, the largest offshore island in Massachusetts, USA, was conducted mostly from 2010-2011 at over 60 sites across the island’s six towns. We document 181 bee species in 31 genera and six families, and historical records of four species recovered only from museum collections and comprising over 14,500 specimen records databased. The fauna is more species-rich and includes a more diverse assemblage of sand specialists (psammophiles) and pollen specialists (oligoleges) than the recorded faunas of other regional islands. Notable finds include the first records of Anthophora walshii Cresson from the northeastern USA since the 1970s; two oligoleges of Maleberry Lyonia ligustrina (L.), Colletes productus Robertson and Melitta melittoides (Viereck); the parasitic Nomada rodecki Mitchell, newly associated with M. melittoides and newly placed within the Nomada basalis species group (previously associated with Melitta in Europe); and two species newly recorded from Massachusetts: Andrena neonana Viereck and Nomada xanthura Cockerell. We note 23 species not recorded from other Massachusetts offshore islands, of which 19 were unrecorded from southeastern Massachusetts. Two bumble bee species in the nominate subgenus Bombus, B. affinis and B. terricola, that have undergone regional declines were recorded historically from Martha’s Vineyard and other islands but not found in this survey. The taxonomic and behavioral composition of the island’s bee fauna are discussed with reference to the fauna of Massachusetts and to comparable recently surveyed mainland and island sites in Massachusetts and New York. Our results underscore the regional roles of maritime habitats underlain by sandy soils in sustaining diversity of bees in addition to Lepidoptera and other well-documented insect groups. Polylectic eusocial bees make it essential to consider taxonomic and life history information, and we made particular effort to survey habitats and host plants likely to contain less abundant or more localized specialist and parasitic species to ensure these were not overlooked among the more abundant and widespread eusocial halictines. Modest overlap between sampling years reinforces the need for multi-year studies.