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United States Department of Agriculture

Agricultural Research Service


item Taylor, David - Dave
item Moon, Roger
item Gibson, Gary
item Szalanski, Allen

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2006
Publication Date: 9/12/2006
Citation: Taylor, D.B., Moon, R., Gibson, G., Szalanski, A. 2006. Genetic and morphological comparisons of new and old world populations of spalangia species (hymenoptera: pteromalidae). Annals of the Entomological Society of America. 99(5): 799-808. Available:

Interpretive Summary: Parasitic wasps are among the most important natural controls for flies that breed in livestock wastes. A great deal of effort has been expended to identify and introduce exotic parasites that may be more effective at locating parsitizing flies than our native species. In order to focus foreign exploration, it is important to understand the relationships between native, previously introduced and exotic species. In this study we examine the relationships among three species of wasps with very broad distributions around the world. New and Old World populations of two of those species, Spalangia cameroni and S. endius were very similar. New and Old World populations of Spalangia nigroaenea, the third species, were very different and probably represent distinct species.

Technical Abstract: The genetic similarity of New and Old World samples of three cosmopolitan Spalangia (Hymenoptera: Pteromalidae) species S. cameroni, S. endius and s. nigroaenea was examined using two ribosomal DNA regions. Two additional North American Spalangia species, S. drosophilae and S. nigra as well as the South American S. gemina and two species of Muscidifurax (Hymenoptera: Pteromalidae) were included to provide information on relative levels of divergence among recognized species. The Internal Transcribed Spacer-1 region was highly variable among Spalangia species with many insertions/deletions making alignment of the sequences difficult. The D2-D3 region of the 28s ribosomal gene and the nuclear rDNA 18s gene were more conserved and allowed for phylogentic analysis. No genetic differentiation was observed among S. cameroni and S. endius samples from Kazakhstan, Russia and North America. New and Old World samples of S. nigroaenea were distinct. The intact ITS-1 amplicon was much larger in the New world samples, 920 bp vs 780 bp in the Old World smaples. Kimura 2-parameter genetic distance between the New and Old World samples was 0.015 for the 28s region. The smallest genetic distance among recognized Spalangia species, S. endius and S. nigra was 0.037 whereas the genetic distance between the two Muscidifurax species, M. raptor and M. zaraptor was 0.004. Based upon these results, the status of S. nigroaenea as a single, cosmopolitan species, needs to be re-examined. Further samples will be needed to determine the affinities of African, Pacific and South American populations as well as elsewhere in Europe, Asia and North America. Further phylogenetic analysis of 6 Spalangia species revealed three groupings: S. cameroni and S. gemina; S. endius and S. nigra; and New and Old World populations of S. nigroaenea. The close relationship between S. endius and S. nigra differs from classifications based upon morphological characters.

Last Modified: 06/27/2017
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