Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 16, 1998
Publication Date: N/A
Interpretive Summary: Parasitic wasps are important tools for managing house flies and stable flies on livestock and poultry farms. The wasps attack the fly in the pupal stage, and numerous studies have shown that releases of these wasps on farms can help control flies while reducing the need for chemical insecticides. Recently, there has been considerable interest in importing exotic wasps that may be superior to some of our native wasp species. However, many wasp species, are difficult to identify using traditional methods, which makes it difficult to determine whether a species introduction in the field has been successful. Scientists at the Center for Medical, Agricultural, and Veterinary Entomology have found that by analyzing the relative amounts of different hydrocarbons on the exoskeleton of three species of wasps (Muscidifurax spp.), they could identify each wasp species correctly, and that the hydrocarbon patterns within each wasp species did not change from one collection site to another. This chemical approach to wasp identification is reliable, rapid, economical, and is as precise as currently available but more complicated molecular methods. The results of this study can be used in quality assurance programs by commercial producers of parasitic wasps to ensure the purity of their colonies.
Technical Abstract: Gas chromatographic analysis of cuticular hydrocarbons of Muscidifurax spp. adult females revealed species-specific patterns of composition that allowed identification of M. raptor, M. zaraptor and M. raptorellus. A total of 18 components, all C29 - C37 alkanes and methylalkanes, accounted for over 90 percent of the total hydrocarbons for all three species. M. zaraptor was characterized by a high ratio (11.9) of 3-MeC31: internal Me2C35's, whereas this ratio was less than 3 for the other species. M. raptorellus was characterized by a low (less than 1) 3-MeC31: 3,7,15-Me3C37 ratio compared with ratios of 3.1 and 6.3 for these components in M. raptor and M. zaraptor, respectively. Three populations of M. raptorellus could be distinguished from one another based on two other component ratios (5- and 7-MeC31: 3Me32, 5- and 7MeC31:3,7- to 3,15-Me2C33) with either 100 percent (Nebraska population) or 90 percent (Chilean and Peruvian populations) certainty. Comparison of M. raptor colonies established from 5 different locations (Florida, France, Germany, Brazil, Hungary) indicated that the hydrocarbon pattern was highly conserved in this species. A dichotomous key to species based on ratios of cuticular hydrocarbon components unambiguously classified the 50 samples of Muscidifurax spp. used to construct the key, plus 5 additional samples form different geographic locations.