title: Effect of chlorpyrifos and monocrotophos on locomotor behaviour and acetylcholinesterase activity of subterranean termites, Odontotermes obesus.
abstract: The acute toxicity of chlorpyrifos and monocrotophos to subterranean termites, Odontotermes obesus (Rambur), has been studied by a paper contact method. The LC50 values for chlorpyrifos and monocrotophos were 0.046 and 0.148 microg cm(-2), respectively. Chlorpyrifos was 3.22-fold more toxic than monocrotophos. The effect of the pesticides on locomotor behaviour (velocity) and head acetylcholinesterase (AChE: EC 3.1.1.7) activity was estimated in LC50-exposed termites at intervals of 4, 8, 12, 16, 20 and 24 h. Chlorpyrifos- and monocrotophos-treated termites showed, respectively, 97 and 88% reduction in locomotor behaviour (velocity) after 24 h. At all time intervals the chlorpyrifos-treated termites exhibited more AChE inhibition and showed greater distorted behaviour than those exposed to monocrotophos. In vitro studies indicated that the I50 value (50% inhibition) for chlorpyrifos against AChE was 8.75 times that of monocrotophos.
authors.affiliation: Toxicology Unit, Biology Division, Indian Institute of Chemical Technology, Hyderabad - 500 007, India. jv@iict.res.in
authors.forename: J
authors.initials: J
authors.lastname: Venkateswara Rao
authors.forename: K
authors.initials: K
authors.lastname: Parvathi
authors.forename: P
authors.initials: P
authors.lastname: Kavitha
authors.forename: N M
authors.initials: NM
authors.lastname: Jakka
authors.forename: R
authors.initials: R
authors.lastname: Pallela
mesh_terms: D000818:Animals; D004390:Chlorpyrifos / Q000494:pharmacology*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D007306:Insecticides / Q000494:pharmacology*; D020049:Isoptera / Q000201:enzymology; D007928:Lethal Dose 50; D008999:Monocrotophos / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D013997:Time Factors
chemical_list: D002800:Cholinesterase Inhibitors; D007306:Insecticides; D008999:Monocrotophos; D004390:Chlorpyrifos