Sex ratio, pupal parasitism, and predation in two declining populations of the bagworm, Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae) |
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| Authors: | DAVID J. HORN ROGER F. SHEPPARD |
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| Affiliation: | Department of Entomology, The Ohio State University, Columbus, Ohio, and Department of Biology, Concord College, Athens, West Virginia |
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| Abstract: | Abstract. 1. Two populations of bagworms were censused in Ohio for 6 and 5 years respectively, to determine the influence of major pupal mortality factors. Bagworm densities declined from 2.3 bags per 30 cm of terminal branch to zero.
2. No single key mortality factor was identified in population trends. Parasitic Hymenoptera were common but variable in effect. Avian predation may have been important in reducing one population, while the other was exterminated after a drastic change in sex ratio to favour males. |
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