Olfactorily mediated attack suppression in the southern grasshopper mouse toward an unpalatable prey.

Predatory behavior toward an unpalatable sympatric prey was examined in the southern grasshopper mouse, Onychomy torridus (Coues). Mice preferred the palatable grasshopper Brachystola magna over the unpalatable secretion-producing grasshopper Taeniopoda eques. Consumption of T. eques decreased 35% while consumption of B. magna remained stable during three nights of testing. Olfactorily mediated attack suppression was demonstrated when O. torridus rejected palatable B. magna which had been coated with 5 ul of T. eques defense secretion. These results show that O. torridus discriminates and is capable of rejecting prey at any point in the prey capture sequence. These are adaptive attributes for a predator like O. torridus, which commonly attacks well-defended or dangerous prey.