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Title: MANDIBULAR TEETH IN CHALCIDOIDEA: FUNCTION AND PHYLOGENY

Author
item HERATY, JOHN - DEPT.OF ENTOM. UNIV. CA.
item Schauff, Michael

Submitted to: Journal of Natural History
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Various species of scale insects and whiteflies cause millions of dollars of damage to U.S. crops annually. The most cost effective way of controlling these insect pests is by biological control using natural enemies. One of the most effective groups of natural enemies is the parasitic wasp family Aphelinidae. This paper reports the discovery of a new morphological character system which has implications for the classification and identification of species of Aphelinidae and characterization of parasitoid species after they have emerged from the host. We also report observations of how this structure is used by the wasp. A better understanding of the relationships of these species to one another will enhance our ability to use biological control to reduce pesticide usage and reduce damage. This information will be of value to taxonomists and regulatory personnel who must identify these insects and to biological control workers.

Technical Abstract: Aphelinidae and Encyrtidae (Hymenoptera: Chalcidoidea) were surveyed for presence of a specialized ventroapical mandibular tooth that is formed through modification of a seta into a stout socketed spine. An almost identical tooth is found in a homologous position in Coccophaginae (Aphelinidae), Calesinae (Aphelinidae or incertae sedis), and Habrolepidini (Encyrtidae), but nowhere else within Chalcidoidea. Although the tooth represents a synapomorphy for genera within each of these higher taxa, it appears to be independently derived on the basis of other morphological and biochemical evidence. Observations of Comperiella bifasciata and Encarsia sp. nr. perniciosi emerging from California Red Scale show that the tooth is used for shearing off pieces of the mummified host remains and the scale cover during formation of the exit hole. The tooth occurs in both sexes, and in taxa with a broad host range such as Encarsia, which attack both hard scales and whiteflies. Problems associated with character homology, function and phylogeny are discussed.