Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2007
Publication Date: 1/1/2008
Citation: Sing, S.E., Arbogast, R.T. 2008. Predatory response of Xylocoris flavipes to bruchid pests of stored food legumes. Entomologia Experimentalis et Applicata. 126:107-114. Interpretive Summary: The need to reduce the risk posed by chemical pesticides to human health and the environment, and at the same time to protect food commodities from damage and contamination by insect pests, has prompted a substantial research effort to develop insect control strategies that reduce or eliminate the need for chemical application. Biological control using other insects that feed upon pest species (natural enemies) is one such control strategy that has received much attention and has shown considerable promise. Scientists at Montana State University, in cooperation with ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, have found that the warehouse pirate bug, a natural enemy that preys upon a wide range of stored food pests, offers an especially promising means of controlling a variety of bean weevils. These weevils, which infest dry beans during storage, cause serious economic loss by consuming and contaminating the beans. The warehouse pirate bug was found to be capable of attacking and killing the adults of five different species of bean weevils. The information provided by this study will be used by scientists to develop biological, chemical-free methods that can be used by farmers and warehouse operators for reducing losses caused by these weevils.
Technical Abstract: Biological control may provide an affordable and sustainable option for reducing losses to pest Bruchidae in stored food legumes, a crucial source of dietary protein. Previous investigations have focused primarily on the role of parasitism in bruchid biological control, while the potential of generalist predators has been comparatively unexplored. The anthocorid true bug Xylocoris flavipes (Reuter) (Hemiptera: Anthocoridae) exhibited a Type II functional response to the majority of cosmopolitan bruchid species evaluated when data were fit to Holling's disc equation. A negative correlation was detected between mean pest species body weight and rate of predation. The rate of attack on adult prey was quite low but fairly consistent, with the larger-sized female predators generally more effective. The eggs and neonate larvae of Acanthoscelides obtectus were the only accessible immature stages among all species examined; predation on A. obtectus eggs and larvae was higher than on any adult bruchids. Mean predator kill of A. obtectus immature stages was 40 first instar larvae or 10-20 eggs per 24 h interval. Further investigation of the biological control potential of X. flavipes against pest Bruchidae is merited due to the predator’s ability to kill adult stages of all prey species evaluated.