Monday, 15 November 2004 - 10:30 AM

Molecular insights into the male genitalia of the Trichogrammatidae (Hymenoptera: Chalcidoidea): Resolutions and prevailing mysteries

Albert Owen, and John D. Pinto, University of California, Riverside, Department of Entomology, 900 University Avenue, Riverside, CA

Members of the family Trichogrammatidae (Hymenoptera: Chalcidoidea) are parasitic on the eggs of other insects, are among the smallest insects, and currently consist of approximately 800 species in ca. 80 genera worldwide. Several classifications of the family have been proposed, though the most commonly used classification is based largely on male genitalia and divides the family into 4 tribes, each with its own genitalic ‘theme’ based on varying levels of simplification. Robustness of the current classification is being tested by molecular investigations focusing on 18S and 28S rRNA. To date, approximately 60% of the currently recognized genera have been sequenced. The molecular phylogeny does not match the relationships predicted by the current classification. Nonetheless, many historically recognized groups have been recovered in our analyses, suggesting that male genitalia are of considerable value for higher level classification. In general, taxa with more plesiomorphic genitalia come out near the base of the phylogeny, while those with more simplified genitalia come out more apical. Even within genera with variable external morphology, their genitalia remain relatively conserved across the genus. The exception to this rule is the genus Ufens Girault which, in spite of its well-conserved external morphology, has genitalic diversity rivaling or surpassing the rest of the family combined. Implications for the family and potential explanations for the diversity of Ufens genitalia will be discussed.

Species 1: Hymenoptera Trichogrammatidae Ufens
Species 2: Hymenoptera Trichogrammatidae Trichogramma
Keywords: morphology, parasitoid

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