Submitted to: Florida Entomologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/15/2008
Publication Date: 12/1/2008
Citation: Rohrig, E.A., Sivinski, J.M., Wharton, R. 2008. Comparison of parasitic hymenoptera captured in malaise traps baited with two flowering plants Lobularia maritima (Brassicales: Brassicaceae) and Spermacoce verticillate (Gentianales:Rubiaceae). Florida Entomologist. 91(4):621-627. Interpretive Summary: Many natural enemies of pest insects rely on flowers, either nectar or pollen, for adult food. However, not all flowers are attractive or useful to all of the many kinds of parasitic wasps. Scientists at the USDA-ARS Center for Medical, Agricultural and Veterinary Entomology in collaboration with colleagues at the University of Florida and Texas A&M University used traps baited with two species of flowering plants to determine which types of parasitoids were attracted to each. One, sweet alyssum, proved to be particularly attractive a subfamily of wasps that are widely used to control fruit flies. In another set of experiments this information was used to isolate the chemical in the floral odor that is responsible for the attraction. This may ultimately lead to a first ever synthetic attractant to monitor the longevity and abundance of mass-released parasitoids.
Technical Abstract: Many adult hymenopterous parasitoids feed on floral nectar, and occasionally pollen. However, flowers differ in both accessibility and attractiveness to these insects. Malaise traps, a type of “passive/interception” trap, were baited with potted flowering plants, Lobularia maritima L. (Brassicaceae) or Spermacocae verticillata L. (Rubiaceae), or left unbaited as controls. These plants have different floral morphologies, but both have been previously used as food-plants for biological control agents. In general, L. maritima captured more Braconidae, particularly Opiinae, than either alternative. Species of this subfamily attack Diptera and certain species are important natural enemies of pest Tephritidae. The roles of plant attractiveness (volatiles) and architecture (trap access) are discussed, as is the possibility of employing L. maritima and/or its products in monitoring or maintaining fruit fly parasitoids.