Smarter baits: The effects of stress on bait aversion and options to avoidthe development of bait aversions

In poisoning operations, sublethal consumption of the toxin, can produce ba it aversion. This decreases the effect of the poisoning and may create prob lems due to the presence of uneaten toxin in the environment. The use of ne w bait additives may prevent aversion development. Here I report the effect s of two bait additives, corticosterone and mifepristone, in altering bait aversion development in rats exposed to the widely used poison, monofluoroa cetate (1080). Corticosterone is a glucocorticoid hormone, released in resp onse to stress. Mifepristone (Ru 38486), inhibits the actions of this hormo ne. Imposed stress as well as administration of corticosterone, decreased c onsumption. Concurrent administration of mifepristone prevented these decre ases. Mifepristone in low doses increased aversion in stressed, but not uns tressed rats. At high doses, mifepristone both increased consumption and de creased aversion in all rats following exposure to 1080. Administration of corticosterone also produced dose-dependent effects on aversion. At low dos es in unstressed rats corticosterone, alone, increased aversion, while at h igh doses in all rats it decreased aversion. Stress, and the hormonal outco me of this state, may thus contribute to aversion by influencing both consu mption and aversion development.