Effects of pollutants on molting and regeneration in crustacea

Abstract

Many environmental pollutants have toxic effects that can alter normal limb regeneration and molting in Crustacea. The most common effect of heavy metals is that of retardation of regeneration of limbs accompanied by a delay in ecdysis; in some cases regeneration is affected without altering the molt cycle. Chlorophenols and dithiocarbamates caused inhibition of regeneration without affecting molting in shrimp. Organic toxicants such as aromatic hydrocarbonsand dioxins also result in a decrease in the growth increment per molt, while DDT was found to accelerate regeneration and molting. A number of toxicants also produce morphological alterations in the regenerated limbs of crabs. These may be relatively minor, such as reduced number of pigment cells, setae, or tubercles in the regenerated limbs (mercury and cadmium), or may be more major deformities, such as abnormal bending in the limb or claw (tributyltin), or defects inchitin formation in the exoskeleton (diflubenzuron). © 1992 by the American Society of Zoologists.