Landscape-Level Patterns of Elevated FS1 Asian Allele Frequencies in Populations of Gypsy Moth (Lepidoptera: Erebidae) at a Northern U.S. Boundary.
From a regulatory perspective, Asian gypsy moth is a species complex consisting of three species of Lymantria and two subspecies of Lymantria dispar (L.), differing from the European subspecies, L. dispar dispar (L.), by having consistently flight-capable females. As such, the invasion potential in North America is thought to exceed that of European gypsy moth. USDA-APHIS therefore has a monitoring program to detect Asian gypsy moth at high-risk introduction pathways. Molecular markers are used to improve the diagnosis of Asian gypsy moth. One such marker, which targets the FS1 locus, detects an allele, FS1-A, prevalent in Asian populations but occurring at low frequencies (3-6%) throughout the European gypsy moth's range in North America. However, some locales, such as Minnesota, exhibit elevated FS1-A frequencies. We studied the distribution of the FS1-A allele in northern Minnesota, 2013-2014, assessing spatial patterns in the distribution of the FS1-A allele using Moran's I and using spatial regression techniques to examine if the FS1-A allele was associated with putative movement pathways. We also used time series analysis to discern if temporal patterns in FS1-A or possible introduction events occurred. Our results indicated that FS1-A occurred randomly in space and time. We found no evidence that elevated FS1-A frequencies were associated with movement pathways or possible immigration events into this region over the two years. Elevated frequencies of the FS1-A allele within this region could be due to genetic drift and allelic surfing along the expanding population front, or to selection of physiological or behavioral traits.
Department of Entomology, University of Minnesota, 1980 Folwell Av., St. Paul, MN 55108 (strei154@umn.edu; BrianAukema@umn.edu).
Marissa A
MA
Streifel
School of Environmental and Forest Sciences, University of Washington, 123 Anderson Hall, 4000 15th Ave., NE, Seattle, WA 98195 (pctobin@uw.edu).
Patrick C
PC
Tobin
Minnesota Department of Agriculture, 625 Robert St. N, St. Paul, MN 55155 (Lucia.hunt@state.mn.us).
Lucia
L
Hunt
USDA APHIS PPQ Science and Technology, Center for Plant Health Science and Technology, 1398 W. Truck Rd., Buzzards Bay, MA 02542 (hannah.nadel@aphis.usda.gov; john.j.molongoski@aphis.usda.gov).
Hannah
H
Nadel
USDA APHIS PPQ Science and Technology, Center for Plant Health Science and Technology, 1398 W. Truck Rd., Buzzards Bay, MA 02542 (hannah.nadel@aphis.usda.gov; john.j.molongoski@aphis.usda.gov).
John J
JJ
Molongoski
Department of Entomology, University of Minnesota, 1980 Folwell Av., St. Paul, MN 55108 (strei154@umn.edu; BrianAukema@umn.edu).
Brian H
BH
Aukema
D063147:Animal Distribution; D000818:Animals; D005787:Gene Frequency; D014644:Genetic Variation; D019476:Insect Proteins / Q000235:genetics*; D008297:Male; D008910:Minnesota; D009036:Moths / Q000235:genetics*
D019476:Insect Proteins
Lymantria dispar; allelic surfing; movement pathway; range expansion; spatiotemporal analysis