Title: Synergist Ratios, Epn Detoxication, Lipid, and Drug-Induced Changes in Carbaryl Toxicity in Megachile pacifica1
Abstract: Megachile pacifica (Panzer) generally became more susceptible to carbaryl as adults aged. LD 50 values for carbaryl toxicity were 240, 166.5, 109.2, and 51.3 μg/g for the 1, 2, 3, and 4-day-old adult male bees. For the female bees, these values were 245.5, 550.5, 289.4, and 262.4 μ/g. Lipid content and in vitro EPN detoxication decreased in both sexes as the bees aged. Synergist ratios were measured. They are the ratio of the LD 50 of carbaryl alone to the LD 50 of carbaryl applied after the synergist piperonyl butoxide. These ratios, which did not correlate with either decreasing LD 50 values or decreasing EPN detoxication in the males, were 12, 21, 42, and 53 for the 1, 2, 3, and 4-day-old bees. female bees the synergist ratios corresponded more closely. They were 23, 49, 11, and 15 as the females aged from 1 to 4 days. The bees were very susceptible to the organo-phosphates monocrotophos, dicrotophos, or Gardona® [2-chloro-1-(2,4,5-trichloro-phenyl) vinyl dimethyl phosphate], (LD 50 < 2 μg/g), but they were quite tolerant the carbamate Landrin® (3,4,5-trimethylphenyl methylcarbamate; 2,3,5-trimethylphenyl methylcarbamate). The use of enzyme-inducing drugs to protect bees from carbaryl poisoning was studied. Among the 3 drugs used, only chlorcyclizine increased the LD 50 value (to ca. 2-fold) in the 4-day-old male. Aminopyrine increased the male's susceptibility carbaryl while phenobarbital had no effect at all. None of the drugs significantly changed the female's susceptibility to carbaryl except aminopyrine which lowered LD 50 from 262.4 to 75.3 μg/g. Studies with in vitro EPN detoxication indicated that all 3 drugs caused increases in microsomal enzyme activity up to 4 or 5-fold and decreases in lipid content of ca. 20–30%.
Publication Year: 1974
Publication Date: 1974-12-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 11
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot