Dispersal Behavior of Rhinoncomimus Latipes Korotyaev
University of Delaware
Mile-a-minute weed weevils, (Rhinocomimus latipes Korotyaev) are biological control agents of mile-a-minute weed (Persicaria perfoliata (L.) H. Gross), an invasive Asian plant that has spread throughout much of the Mid-Atlantic United States. I set up two types of experiments: a habitat island experiment to look at dispersal of weevils in response to density and whether or not they prefer dispersing to plants with or without other resident weevils; and two distance dispersal experiments to study how far the weevils would disperse in response to a deteriorating habitat and if there were any differences between male and female dispersal behavior. Weevils did not disperse in response to overcrowding, but rather to a deteriorating habitat. They did not disperse at different rates to plants with or without conspecifics. Females tended to disperse farther away from the deteriorating habitat than males; both sexes were probably maximizing their own reproductive success. Males probably remained close to the deteriorating habitat because there was an established weevil population present. This population would provide females with whom the males could mate. Once females have been mated, they do not need to exist near other weevils. Instead, they flew to farther away locations of healthy mile-a-minute weed so that their young would mature in an optimum habitat and have the best chance of survival.