Developmental Performance of the Milfoil Weevil,Euhrychiopsis lecontei(Coleoptera: Curculionidae), on Northern Watermilfoil, Eurasian Watermilfoil, and Hybrid (Northern × Eurasian) Watermilfoil

Abstract

Abstract Eurasian watermilfoil (Myriophyllum spicatum L.) is a non-native, aquatic, invasive species common throughout North America. The native aquatic milfoil weevil (Euhrychiopsis lecontei Dietz), whose natural host is the native northern watermilfoil (Myriophyllum sibiricum Komarov), has expanded its range to include M. spicatum. Previous studies show that it prefers the non-native Eurasian watermilfoil over native watermilfoils for feeding and oviposition. Previous studies also suggest that milfoil weevils that develop on M. spicatum have shorter development times and a greater mass. Eurasian watermilfoil and northern watermilfoil have hybridized, and hybrids can be more invasive than their parent species. One hypothesized mechanism for increased invasiveness in the hybrid watermilfoil is resistance to the milfoil weevil. To test for resistance, we compared development times, mass, and survival of the milfoil weevil reared on Eurasian, northern, and the Eurasian × northern hybrid watermilfoils. We fo...