Predation on the Colorado Potato Beetle (Coleoptera: Chrysomelidae) by Phalangium opilio (Opiliones: Phalangidae)

Abstract

The predatory role of Phalangium opilio (L.) in the population dynamics of Leptinotarsa decemlineata (Say) was evaluated by studying its seasonal occurrence and synchrony with the beetle in fields of cultivated potato, Solanum tuberosum L. Consumption rates of different Colorado potato beetle life stages by P. opilio were estimated in the laboratory and field. Results suggest that P. apilio is not well synchronized temporally with Colorado potato beetle prey. Laboratory studies of P. opilio feeding showed that predation is restricted to Colorado potato beetle eggs and first and second instars; a sigmoid functional response to increasing prey densities is exhibited. Results of a field cage study suggest P. apilio may not be a major source of mortality for the Colorado potato beetle.