Mass Trapping with Blacklight: Effects on Isolated Populations of Insectsl
Mass Trapping with Blacklight: Effects on Isolated Populations of Insectsl w. W. CANTELO; J. L. GOODENOUGH," A. H. BAUMHOVER,' J. S. SMITH, JR.,' J. M. STANLEY,· AND T. J. HENNEBERRY' USDA ABSTRACT Blacklight traps were operated for 43 months at a density of 3 per square mile on an isolated tropical island, St. Croix, U. S. Virgin Islands, to determine the effect on popu- lations of 25 insect species. Subsequently, the density of traps was reduced to 0.3 per square mile for] 8 months, and changes in the collections were noted. The test species were: Agrius cingulatus (F.), Callionima ramsdeni (Clark), Eumor- pha vitis (L.), Hyles lineata (F.), Manduca rustica harterti (Rothschild), Manduca sexta (L.), Xylophanes pluto (F.), X. tersa (L.), Heliothis virescens (F.), H. zea (Bod- die), Ecpantheria icasia (Cramer), Gryllus assimilis (F.), Microcentrum triangulatum Downloaded from https://academic.oup.com/ee/article/3/3/389/2395318 by guest on 29 September 2021 Brunner, N eoconocephalus triops (L.), Schistocerca pallens (Thunberg), A crosternum marginatum (Palisot De Beauvois), Loxa pilipes Horvath, Nezara viridula (L.), ladera rufofusca Barber, Bothynus cuniculus (F.), Phyllophaga microphylla Moser, P. por- toricensis (Smyth), Calosoma alternans alternans (F.), Conoderus sp. and Lacon sub- costatus (Candeze). Many species had decreased populations as measured by BL trap collections during the 43 months, and within a year after the trap density was reduced most had surges to population levels as high or higher than those recorded during masstrapping. Lepidop- teran population indices were more affected than indices of other orders. Generally, most decreases and increases in populations appeared to be related to the trapping, but the numbers of some species that were removed by the traps were so low that any effect was indirect.
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