Aphidiinae wasps use an ovipositor at the rear of their abdomen to lay their eggs inside aphids. Eventually, the development of the parasitoid larva is fatal for the aphid concerned. The authors predicted that the areas littered with exuviae decoys would be seen as poor hunting grounds by the wasps who would move on to other patches. In fact, Muratori describes how, “We found that parasitoid females spent more time in patches that contained exuviae than in patches that contained only aphids, suggesting that these females either did not recognize exuviae as low quality hosts or needed time to correctly identify them”.

The potential gain for the individual aphids comes from the increased time available to escape from the colony while the wasps are investigating the decoys. According to the authors, “Aphids release an alarm pheromone when they are under parasitoid attack, giving other aphids time to escape. In nature this is achieved by dropping off the plant”.