ARS | Publication request: PATCH EXPLOITATION BY FEMALE RED FLOUR BEETLES, TRIBOLIUM CASTANEUM

Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 21, 2003
Publication Date: July 15, 2003
Citation: m CAMPBELL, J.F., RUNNION, C. PATCH EXPLOITATION BY FEMALE RED FLOUR BEETLES, TRIBOLIUM CASTANEUM. JOURNAL OF INSECT SCIENCE 3:20:1-8. 2003.

Interpretive Summary: The red flour beetle, Tribolium castaneum, has had a long association with human stored food and can be a major pest in buildings used for the processing and storage of grain-based food. In this type of environment food can occur in small discrete patches. Persistence of beetle populations in buildings results from their ability to find and exploit these small patches of food. The size of a food patch influences how many offspring can survive from egg to adult. Thus, for any given amount of food there is an optimal number of eggs that should be laid to maximize offspring production. We determined the number of adult progeny that could be produced from different size flour patches. The number of eggs that female red flour beetles actually laid in patches was also measured. The number of eggs females laid in a patch of flour increased as the size of the patch increased and the number was consistent with the optimal number of eggs for a patch of that size. Our results indicate these beetles have a relatively sophisticated ability to evaluate patch quality when making decisions about where and how many eggs to lay. This work highlights the abilities of this pest to find and exploit small patches of spillage and illustrates the importance of sanitation programs to prevent insect persistence in mills and other food processing and storage facilities.

Technical Abstract: The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera:Tenebrionidae) has had a long association with human stored food and can be a major pest in anthropogenic structures used for the processing and storage of grain-based products. Anthropogenic structures are fragmented landscapes characterized by spatially and temporally patchy resources. Here we investigate the ability of female T. castaneum to evaluate the quality of small patches of food and to adjust the number of eggs they lay per patch (i.e., clutch size) to maximize fitness gains. In multiple choice, paired choice and no choice experiments females tended to lay more eggs in larger amounts of flour. The number of eggs that they lay in a patch of flour was consistent with that predicted to optimize production of adults from that patch (i.e., the Lack clutch size). Progeny size was only significantly impacted in the smallest patch sizes.