The research investigated how the striped cucumber beetle, Acalymma vittatum, detects the presence of a natural predator, the wolf spider Rabidosa rabida. Field observations conducted at night in squash gardens reveal that the presence of a wolf spider within 10 cm of groups of feeding beetles increases by ca 2x the rate at which beetles fly away from the plant. In order to understand how the striped cucumber beetle detects the spider, we conducted experiments in two-chambered laboratory microcosms in which the beetle and the spider were physically separated. In the laboratory microcosm the presence of a wolf spider decreased the time the beetles spent feeding on the squash plant, but the beetles did not respond to the presence of a similarly sized and non-dangerous arthropod, the cricket Achaeta domestica. In two experiments conducted in which tactile or visual cues from the wolf spider were blocked, the beetle continued to display an antipredator response. This surprising result prompted an additional experiment in which possible tactile cues were more completely isolated, and in which visual cues were also blocked as part of a 2x2 factorial design. This experiment will reveal the degree to which visual and tactile cues interact, and whether or not auditory or olfactory signals may reveal the presence of spiders to striped cucumber beetles. Understanding how pests detect and react to predators such as wolf spiders will increase our ability to manipulate predators as biocontrol agents.
Species 1: Coleoptera Chrysomelidae Acalymma vittatum (striped cucumber beetle)
Species 2: Araneae Lycosidae Rabidosa rabida (wolf spider)
Keywords: biocontrol, wolf spider
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA