Dieldrin behavioral effects

Turning now to indirect effects of neurotoxic pollutants, the status of predators and parasites can be affected by reductions in numbers of the species that they feed upon. Thus, the reduction in numbers of a prey species due to a behavioral effect can, if severe enough, cause a reduction in numbers of a predator. Also, as mentioned earlier, behavioral effects upon a prey species may lead to selective bioaccumulation of persistent neurotoxic pollutants such as DDT and dieldrin by predators thus, a behavioral effect may be hazardous for predator and prey alike ... 

Researchers were also able to establish the link between declines of other predatory species such as the European sparrowhawk and the use of organo-chlorine pesticides other than DDT. For instance, the cyclodiene insecticides aldrin, dieldrin, and he-ptachlor used as seed treatments caused massive mortality of both seed-eating species and their predators. All of the insecticides had the following points in common they were highly soluble in fats and refractory to metabolism. The impacts on the predatory species typically take place in periods of food stress when fat soluble residues are released from fat stores and returned into general circulation. In a food-stressed individual, the brain remains as the most lipid rich tissue and this is where contaminants move to. Toxicity results when threshold values in brain tissue are exceeded. At sublethal levels, documented effects of cyclodiene insecticides in birds have included changes in their reproductive, social, and avoidance behaviors. 

Burchfiel, J.L., Duffy, F.H., Sim, V.M., 1976. Persistent effects of sarin and dieldrin upon the primate electroencephalogram. Toxicol. Appl. Pharmacol. 35,365-379. Bushnell, P.J., Padilla, S.S., Ward, T, et al, 1991. Behavioral and neurochemical changes in rats dosed repeatedly with diisopropyl fluorophosphate. J. Pharmacol. Exp. Ther. 256, 741-750. 

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