Elevated Copper Levels during Larval Development Cause Altered Locomotor Behavior in the Adult Carabid Beetle Pterostichus cupreus L. (Coleoptera: Carabidae)

Abstract

It is generally believed that copper causes changes in carabid communities indirectly by reducing food availability, because these animals are frequently found to have only slightly elevated metal contents even close to pollution sources. Using computer-centered video tracking, the locomotor behavior of adult Pterostichus cupreus carabid beetles was quantified after being raised on copper-contaminated food and soil during larval development. Copper was found to have an acute toxic effect measured in larval mortality, to cause a slight increase in the developmental period of males, but not to effect the emergence weights of adults of either sex. This toxic effect on the larvae was preserved through pupation to the surviving adults, which were normal in size and appearance, but displayed a dramatically depressed locomotor behavior. Copper analysis of these adults revealed that copper levels were either the same as or only slightly elevated in comparison with controls. The findings suggest that the altered locomotor behavior is associated with copper-induced internal structural damage during larval development and therefore expresses a prolonged or permanent effect. Such changes in locomotor behavior are likely to reduce the fitness of the animal under field conditions.