Toxicity
The eastern tent caterpillar has been linked to mare reproductive loss syndrome, but the exact mechanism by which the caterpillar triggers abortion in horses has yet to be determined. Experimental studies have shown that when pregnant mares are fed eastern tent caterpillars, they abort. The caterpillars of this species often feed on the highly cyanogenic black cherry tree (Prunus serotina) and the mares were originally thought to abort in response to the cyanide they consumed along with the caterpillars. However, that hypothesis was disproven. In another study, the necropsy of a mare fed eastern tent caterpillars showed fragments of the caterpillar's setae had embedded in the gut wall, leading investigators to hypothesize these invasive fragments may allow infective agents to pass into the animal's blood stream, then travel to the placenta, initiating an abortive event.
Read more about this topic: Eastern Tent Caterpillar