The parasites would lie in wait on the leaves, sometimes for ages.
"In laboratory colonies, mating can occur over many hours," said Laumann, who explained that lengthy copulation is likely a male strategy to ward off competitors in high-density population settings.
Female stink bugs lay eggs right after mating, so the eavesdropping female parasites were then in a prime position to colonize the eggs.
Rex Cocroft, associate professor of biological sciences at the University of Missouri-Columbia, told Discovery News that the study "is a nice piece of work."
"Plant-born vibrational signaling is one of the most widespread forms of communication in the animal kingdom, second only to chemical communication, but is has been seriously under-studied compared to other forms," he said.
Cocroft added, "This paper is exciting because, in a recent review, my colleague Dr. Rafael Rodriguez and I predicted that this form of eavesdropping by predators would be found, so it's nice to see such a prompt confirmation of our prediction!"
Both Cocroft and Laumann think it is likely other mating vibration eavesdroppers exist in nature. These might include spiders, other parasites and certain predators.
The study is published in the current issue of Animal Behavior.
