Survey for winter moth, Operophtera brumata L. (Lepidoptera: Geometridae) in northeastern North America with pheromone-baited traps and hybridization with the native Bruce spanworm, Operophtera bruceata (Hulst)

Authors: ELKINTON, J.S - University Of Massachusetts; BOETTNER, G.H. - University Of Massachusetts; SREMAC, M. - University Of Massachusetts; GWIAZDOWSKI, R. - University Of Massachusetts; HUNKINS, R.R. - University Of Massachusetts; CALLAHAN, J. - University Of Massachusetts; SCHEUFELE, S.B. - University Of Massachusetts; DONAHUE, C.P. - Maine Department Of Conservation; PORTER, A.H. - University Of Massachusetts; Khrimian, Ashot; WHITED, B.M. - University Of Massachusetts; CAMPBELL, N.K. - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/4/2009
Publication Date: 3/1/2010
Citation: Elkinton, J., Boettner, G., Sremac, M., Gwiazdowski, R., Hunkins, R., Callahan, J., Scheufele, S., Donahue, C., Porter, A., Khrimian, A., Whited, B., Campbell, N. 2010. Survey for winter moth, Operophtera brumata L. (Lepidoptera: Geometridae) in northeastern North America with pheromone-baited traps and hybridization with the native Bruce spanworm, Operophtera bruceata (Hulst). Annals of the Entomological Society of America. 103(2):135-145.

Interpretive Summary: Insect pests cause significant damage to crops and forest, and monitoring their populations aids greatly to reducing the pesticide use and biological control. Pheromones, or chemicals that trigger a natural behavioral response in another member of the same species, are commonly used as baits for sampling insect populations. The winter moth is an invasive species that attacks a wide variety of hardwoods and conifers. The insect is native to Europe but has become established in at least three areas of North America including southeastern New England. The pheromone of the winter moth is known but it also attracts closely related native species, Bruce spanworm, which is visually indistinguishable from winter moth, thus complicating analysis of pheromone-baited traps. We distinguished between the two species by examining male genitalia and sequencing the genes. We identified six segments of DNA that routinely distinguished winter moth and Bruce spanworm, of which three were always diagnostic. Thus, by conducting DNA analyses we identified the regions were winter moth occurred but we have also been able to identify regions were both species co-existed and even produced hybrids. The results of this study are of interest to entomologists involved in the research of potential pest control compounds, and to State and Federal agencies involved in monitoring and controlling insect pests of agriculture and forest.

Technical Abstract: We used pheromone-baited traps to survey the distribution of winter moth, Operophtera brumata L., a new invasive defoliator from Europe in eastern New England. The traps also attracted Bruce spanworm, Operophtera bruceata (Hulst), native to North America. We used pheromone-baited traps to survey the distribution of winter moth, Operophtera brumata L., a new invasive defoliator from Europe in eastern New England. The traps also attracted Bruce spanworm, Operophtera bruceata (Hulst), native to North America. We distinguished between the two species by examining male genitalia and sequencing the mitochondrial cytochrome oxidase subunit one (COI) gene, the DNA barcoding region. In 2005, we recovered winter moths at sites stretching from eastern Long Island, southeast Connecticut, all of Rhode Island, eastern Massachusetts, coastal New Hampshire, and southern coastal Maine. At sites further west and north we captured only Bruce spanworm. In 2006 we confirmed that both winter moth and Bruce spanworm are present in Nova Scotia and in coastal Maine, but only Bruce spanworm was recovered in coastal New Brunswick, Pennsylvania, Vermont or Quebec City. In 2007 we collected Bruce spanworm, but no winter moths, in New Brunswick and the interior areas of Maine, New Hampshire and New York. Winter moth and Bruce spanworm differed in the COI sequence by 7.45% of their nucleotides. The prevalence of intermediate genitalia in the zone of overlap suggested that hybridization between the two species may be occurring. To confirm the presence of hybrids, we sequenced the nuclear gene, glucose-6-phosphate dehydrogenase (G6PD). We identified six nucleotides that routinely distinguished winter moth and Bruce spanworm, of which three were always diagnostic. We showed that eggs produced by hybridizing the two species in the lab contained copies of both species at these six sites. We found that most of the moths collected in the field with intermediate genitalia had winter moth CO1 and G6PD sequences and thus were not hybrids (or at least F1 hybrids). We found 3 hybrids out of 158 moths with intermediate genitalia in the region where both species were caught. We conclude that hybrids occur in nature, but are not as common as previously reported. Introgression of genes between the two species may still be significant.