Impaired burrowing activity in earthworms (Pheretima posthuma) related to AChE inhibition caused by the carbamate carbaryl was studied by Gupta and Sundararaman (1991). They found that the ability of the earthworm to burrow in soil decreased in a dose-response fashion over the entire range of concentrations of carbaryl that were studied. The activity of AChE and locomotory behaviour in the carabid beetle (Pterostichus cupreus) exposed to dimethoate was studied by Jensen et al. (1997) In the case of males, all locomotory indices (path length, time during which the organism is active, average velocity, stops per walked metre and turning rate) were affected at the lowest dosage. Females were less affected, despite the fact that the degree of inhibition of AChE was similar.