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Science 29 May 1964:
Vol. 144. no. 3622, pp. 1148 - 1149
DOI: 10.1126/science.144.3622.1148
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Articles

Daily Rhythm in the Susceptibility of an Insect to a Toxic Agent

Charles L. Cole 1 and Perry L. Adkisson 1

1 Department of Entomology, Texas A&M University, College Station

Adult boll weevils exhibited a daily rhythm in their susceptibility to standardized doses of the insecticide, methyl parathion. The mortality produced by the insecticide was intimately related to the time of day at which the toxicant was applied. The rhythm appeared to be photoperiodically entrained and, regardless of the length of day or "clock time-of-day of treatment," a period of greatest resistance always occurred at dawn and recurred at 6-hour intervals throughout the 24-hour cycle. The greatest difference in response occurred in a photoperiod having 10 hours of light per 24-hour cycle. Here, the same dose of methyl parathion killed approximately 10 percent of the weevils treated at dawn but almost 90 percent of those treated only 3 hours later.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Diurnal Rhythm of Sensitivity of Cotton Seedlings to Herbicides.
J. G. Gosselink and L. C. Standifer (1967)
Science 158, 120-121
   Abstract »    PDF »
Pentobarbital Sodium: Variation in Toxicity.
H. A. Lindsay and V. S. Kullman (1966)
Science 151, 576-577
   Abstract »    PDF »


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