Location: Invasive Plant Research LaboratoryTitle: Parasitoids attacking larvae of a recently introduced weed biological control agent, Neomusotima conspurcatalis Warren (Lepidoptera: Crambidae): key to species, natural history, and integrative taxonomy Author
Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2012
Publication Date: 11/14/2012
Publication URL: http://handle.nal.usda.gov/10113/57879
Citation: Boughton, A.J., Kula, R.R., Gates, M.W., Zhang, Y., Nunez, M., O'Connor, J., Whitfield, J.B., Center, T.D. 2012. Parasitoids attacking larvae of a recently introduced weed biological control agent, Neomusotima conspurcatalis Warren (Lepidoptera: Crambidae): key to species, natural history, and integrative taxonomy. Annals of the Entomological Society of America. 105:753-767. Interpretive Summary: A central component of classical biological control theory is the idea that introduced agents are not subject to population regulation by co-evolved, specialist natural enemies within the introduced range, which in theory allows their populations to increase rapidly and exert a suppressive effect on the target pest or weed. In this study, we monitored field populations of a recently introduced weed biocontrol agent, Neomusotima conspurcatalis (Lepidoptera: Crambidae) in Florida to investigate parasitism by native parasitoids and to assess the overall rate of parasitism. Collections of 50 mixed-instar N. conspurcatalis larvae were made from sites every few months, from August 2008 through November 2010, and were returned to the lab for rearing. Six native parasitoid species were reared from larvae of N. conspurcatalis. Five of these species Rhygoplitis choreuti, Stantonia pallida, Elasmus apanteli, Hyphantrophaga sellersi and an unidentified Cotesia sp. were determined to be primary parasitoids of the biocontrol agent. The sixth species, Mesochorus apantelis, was determined to be a hyperparasitoid of R. choreuti. Across 22 collections, totaling 1100 N. conspurcatalis larvae made from three sites, overall emergence of parasitoid wasps was 6.8 % and N. conspurcatalis adults was 73.6 %. Rhygoplitis choreuti was the most commonly reared species, accounting for 81 % of the parasitoid adults reared. We provide illustrations and a partial key to these species. We describe what is known about their natural histories and host ranges, and discuss accumulation of native parasitoids on introduced weed biocontrol agents.
Technical Abstract: The extent to which introduced weed biocontrol agents are subject to attack by generalist natural enemies within the area of introduction is believed to be an important determinant of program success. We monitored larval populations of a recently introduced weed biocontrol agent, Neomusotima conspurcatalis Warren, at field sites in Florida to investigate parasitism by native parasitoids and to assess the overall rate of parasitism. Of six native parasitoid species reared from wild larvae of N. conspurcatalis, five, Rhygoplitis choreuti (Viereck), Stantonia pallida (Ashmead), Elasmus apanteli Gahan, Hyphantrophaga sellersi (Sabrosky), and an unidentified Cotesia sp. were primary parasitoids of the biocontrol agent. The sixth species, Mesochorus apantelis Dasch, is likely a hyperparasitoid of R. choreuti. From 1,100 N. conspurcatalis larvae collected from three sites, adult parasitoids emerged from 6.8% of those larvae and 73.6% of the N. conspurcatalis developed to adulthood. R. choreuti was the most common parasitoid, accounting for 81% of adults reared. Photographs of parasitoid species are provided, aspects of their natural histories and host ranges are described, and accumulation of native parasitoids on introduced weed biocontrol agents is discussed.