Polyphagy complicates conservation biological control that targets generalist predators

Published source details Prasad R.P. & Snyder W.E. (2006) Polyphagy complicates conservation biological control that targets generalist predators. Journal of Applied Ecology, 43, 343-352.
Share Tweet Email

This study is summarised as evidence for the following.

	Action	Category
	Create beetle banks Action Link

Create beetle banks

A replicated, controlled trial study in 2003-2004 at three organic mixed vegetable farms in British Columbia, Canada and Washington, USA and a series of replicated, controlled field cage experiments at a research station in Washington, USA (Prasad & Snyder 2006) found fields with beetle banks had higher beetle (Coleoptera) activity densities than fields without banks (figures not given). However predation rates of housefly Musca domestica eggs were not associated with activity densities of either small beetles (< 1 cm long ground beetles (Carabidae) and rove beetles (Staphylinidae)) or the large ground beetle Pterostichus melanarius. Small beetle activity densities were reduced when P. melanarius individuals were added to 2 x 2 x 2 m caged areas of a radish Rhaphanus sativus field and the number of housefly eggs predated was significantly reduced. The number of housefly eggs predated was lower when alternative aphid (Aphididae) prey were present. Beetle banks 1.5 x 30-60 m (two banks 50 cm high, two field level) sown with orchardgrass Dactylis glomerata were established in April-June 2002. Five housefly eggs were placed on a 1 cm² peat block and covered with 0.5 cm soil at plant bases, five times/field.