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United States Department of Agriculture

Agricultural Research Service


item Stapel, J
item Ruberson, John
item Gross, Harry
item Lewis, Wallace

Submitted to: Ecological Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Plant feeding insects are costly pests of agricultural crops. Resistance and residue problems with conventional pesticides have caused scientists to seek better ways to use natural enemies for the control of insect pests. Understanding natural enemies and how they interact with crops and crop pests is essential to their dependable use in pest control. ARS scientists at Tifton, GA and their University of Georgia colleagues are seeking to better understand factors that influence the fitness of parasitic flies, which attack the caterpillar stage of Spodoptera exigua (beet armyworm). Studies showed that maximum parasitic fly fitness and, thereby, biological control benefit is derived when females allocate only 1-2 progeny per host caterpillar. This information has important implications for designing mass rearing and release pest control strategies involving the use of this parasitic fly

Technical Abstract: Possible strategies were investigated which may be used by adult females of the tachinid parasitoid, Lespesia archippivora, for improving reproductive fitness. The study contains useful implications for theoretical ecology and biological control. Results showed that L. archippivora was able to successfully parasitize all instars of the host Spodoptera exigua. Puparial weight of the female parasitoid, which was positively correlated to egg load, decreased with increasing brood size but was not influenced by host size. In female biased broods the puparial weight reduction was more dramatic. By consistently allotting small broods to hosts, the adult parasitoid may produce highly fit female offspring. This strategy is confirmed by field observations, which showed that collected S. exigua larvae of all instars produced small brood sizes of L. archippivora

Last Modified: 06/26/2017
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