FEEDING BEHAVIOUR, DISPERSAL, AND COMMUNITY DYNAMICS OF CARABIDAE FOUND IN NOVA SCOTIA LOWBUSH BLUEBERRY FIELDS

Abstract

Carabidae can be important pest control agents in many agricultural systems, and research on lowbush blueberry carabid communities is underdeveloped. In laboratory no-choice test experiments, I showed that Pterostichus mutus (Say) and Poecilus lucublandus (Say) did not feed on weed seeds commonly found in lowbush blueberry fields. I also did two field experiments that explored different aspects of Carabidae ecology. In the first, I measured the diversity and abundance of Carabidae in lowbush blueberry fields with respect to time and distance from field edge by setting up traps in a straight line from the surrounding forest edge to the center of 6 vegetative fields. I showed that carabid diversity did not change with distance from field edge over this summer season, but abundance increased linearly. In the second, I investigated Harpalus rufipes (De Geer) dispersal by measuring how far individuals may move over time by setting up a series of concentric circles and releasing marked individuals in the center. I developed a theoretical framework that estimates how many marked individuals are in the area based on number of beetles detected and probability of detection. I found that H. rufipes moved on average 5.38 (95% CI = 2.46 to 8.30), 14.47 (95% CI = 8.57 to 20.37), and 20.73 (95% CI = 8.98 to 32.48) m at 5, 29, and 53 hours respectively. These values are relatively close to that of other Carabidae and give us insight on how fast the population of H. rufipes may disperse in vegetative lowbush blueberry fields. The theoretical framework I developed provides methodological refinements for Carabidae dispersal research.