Repopulation by Aquatic Insects in Streams Sprayed with DDT

Author： HASTINGS ELLSWORTH KITTAMS WALTER H. PEPPER J. H.

Publisher： Entomological Society of America

ISSN： 1938-2901

Source： Annals of the Entomological Society of America, Vol.54, Iss.3, 1961-05, pp. : 436-437

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Population changes in Ephemerida, Trichoptera, and Plecoptera in two high-gradient mountain streams were studied over a 4-year period, following a large scale spray operation. A drastic and widespread reduction in all forms took place immediately after spraying. Trichopterans in cases of the type constructed by the family Leptoceridae were extremely numerous before spraying. No live specimens of this form were obtained during the succeeding 4-year period. Over this period, increase in numbers of Ephemerida in one stream was linear. Analysis of variance tests showed that, in every other instance, no numerical relationship existed in the repopulation of ephemerids or trichopterans. Population numbers of these two forms did not level off until 3 years after spray application. Populations of plecopterans leveled off the year following the spraying.