|CAPSHAW, G. - University Of Maryland|
Submitted to: Proceedings of the Entomological Society of Washington
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2015
Publication Date: 7/15/2015
Citation: Goldstein, P.Z., Morita, S.I., Capshaw, G. 2015. Stasis and flux among Saturniidae and Sphingidae on Massachusetts' (USA) offshore islands and the possible role of Compsilura concinnata (Meigen) as an agent of mainland New England moth declines. Proceedings of the Entomological Society of Washington. 117(3):347-366.
Interpretive Summary: Rapid changes in the faunas of large moths such as sphinx moths and giant silk moths reflect landscape-level impacts such as the expansion and contraction of agricultural areas at scales large enough to be of economic significance. For several decades, entomologists have observed declines of Sphinx moths and giant silk moths and explained them as potential non-target impacts of a parasitoid fly originally introduced to control gypsy moths and other forest pests. Based on a comparison of historical and current records, we determined: (1) that the sphinx moth faunas of both the large offshore islands (Nantucket and Martha's Vineyard) were more unstable than their silk moth faunas; (2) that certain recent declines parallel possible mainland trends; (3) that species in one subfamily account for all recent colonization events by silk moths and; (4) that the fly does not appear to have established itself on Martha's Vineyard, where the silk moth fauna is most diverse and intact. These data are intended for scientists encountering sudden changes in lepidopteran faunas or who are otherwise involved with insect faunistic studies.
Technical Abstract: The lepidopteran fauna of Massachusetts’ offshore islands (USA), particularly Martha’s Vineyard and Nantucket, has been well-characterized, and comprises intact assemblages of disjunct, regionally rare, habitat-specialized, and otherwise threatened species that have declined elsewhere in New England. These include the only persistent and extant population of Eacles imperialis (Saturniidae: Ceratocampinae) in New England, one of at least three ceratocampines to have undergone partial or total extirpation from the region. Examining historical and recent records within two groups—Saturiidae and Sphingidae—that have exhibited varying degrees of flux over time, we compare these islands and identify taxonomic and ecological components of their faunas that appear historically volatile. After reviewing suspected agents of these declines, including the introduced generalist parasitoid Compsilura concinnata (Diptera: Tachinidae), and present preliminary capture data consistent suggesting it has not been established in the presence of E. imperialis. The lack of verified records of C. concinnata fails not to corroborate its selective role in the differential decline of certain large moths.