Cricket mothers are long gone by the time their infants hatch, so one would assume that cricket parents have little effect on their offspring’s behavior. Not so, according to a new study in the American Naturalist which proves that mother crickets have the potential to teach their offspring—while still in their eggs—about the hazards of spiders.
To test how crickets learn to avoid spiders, researchers covered a wolf spiders’ fangs with wax to render it harmless and then placed it into an enclosure with pregnant crickets. The spider could hunt the crickets to its heart’s desire, but couldn’t kill them. A second enclosure was left spider-free.
When the baby crickets hatched, researchers discovered major behavioral differences between the crickets whose mothers had faced stalking spiders and those from the spider-free enclosure. Crickets from spider-exposed mothers proved far more wary of wolf spiders: staying hidden 113 percent longer than crickets whose mothers hadn’t met a spider. The crickets with a spider-exposed mother were also found to be more likely to ‘freeze’ when they ran into spider silk or feces, a behavior that could save them from being eaten. Not surprisingly, crickets whose mothers’ had braved spiders had a higher survival rate when up against the predaotor.
The same results were found in the wild. Collecting pregnant crickets from their natural habitat, the researchers found that the offspring behaved differently toward spiders—i.e. more cautious or less so—in correlation with whether or not spiders were common or scarce in their mothers’ habitat.
The researchers don’t know how this transfer of information from mother to unhatched crickets occurs, but they speculate that anxious encounters with spiders may release a hormone in the mother that influences the development of her embryos.
Citation: Jonathan J. Storm and Steven L. Lima, “Mothers Forewarn Offspring about Predators: A Transgenerational Maternal Effect on Behavior.” American Naturalist 175:3 (March 2010).
Related articles
Researchers catch new cricket species going where no cricket has gone before
(01/13/2010) East of Madagascar, on the small island of Reunion, researchers have made a remarkable discovery: a cricket that pollinates an orchid. The cricket, which is also a species new to science, was caught by a motion sensitive camera pollinating the orchid, Angraecum cadetii. The genus Angraecum orchid is usually pollinated by moths, but cadetti‘s nectar-spur opening is just the right shape for the cricket, known as the ‘raspy cricket’.
Sophisticated flying methods allow insects to hitchhike on fast winds
(02/04/2010) Researchers have long been fascinated by how insects migrate thousands of kilometers, for example from Britain to the Mediterranean. A new study, published in Science shows that although tiny, insects are not at the mercy of winds as expected. Instead they employ sophisticated flight behaviors to use fast winds to their advantage.
Loss in biodiversity may be killing bees
(01/20/2010) A decline in diverse plants species on which to feed may be causing a similar decline in bee survival, according to a new paper in Biology Letters.