HR: 11:15h
AN: NB22D-04    [Abstracts]
TI: The Developmental Performance of the Milfoil Weevil, Euhrychiopsis lecontei (Coleoptera: Curculionidae), on Northern Watermilfoil, Eurasian Watermilfoil, and Hybrid (Northern x Eurasian) Watermilfoil
AU: * Roley, S S
EM: role0013@umn.edu
AF: Conservation Biology Program, Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota - Twin Cities, 200 Hodson Hall 1980 Folwell Avenue, Saint Paul, MN 55108 United States
AU: Newman, R M
EM: RNewman@umn.edu
AF: Conservation Biology Program, Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota - Twin Cities, 200 Hodson Hall 1980 Folwell Avenue, Saint Paul, MN 55108 United States
AB: The aquatic milfoil weevil (Euhrychiopsis lecontei) has expanded its range from the native northern watermilfoil (Myriophyllum sibiricum) to the non-native Eurasian watermilfoil (Myriophyllum spicatum). Previous studies show that it prefers M. spicatum over M. sibiricum for feeding and oviposition and that weevils that develop on M. spicatum are larger and have shorter development times. Eurasian and northern watermilfoil have hybridized, and this hybrid has been hypothesized to be more invasive by exhibiting resistance to the milfoil weevil. To test for resistance, we compared development times, mass, and survival of the milfoil weevil on Eurasian, northern and hybrid watermilfoils. Weevil development was followed from egg to adult on individual rooted plants (n = 17 to 20 for each taxa). Mean development times (19.7 to 20.3 d) and mean adult eclosion mass (1.3 to 1.5 mg) were comparable and not significantly different. Weevil survival rates differed significantly among the taxa and were lowest on northern (45%), intermediate on the hybrid (61%), and highest on Eurasian watermilfoil (88%), but stem diameter may account for some of these differences. This study suggests that hybrid watermilfoil is not exceptionally resistant to milfoil weevil herbivory; rather it possesses resistance intermediate between the native and exotic hosts.
DE: 1851 Plant ecology
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly