A mother's care sometimes knows no boundaries, a new study on crickets and spiders has shown.
Jonathan Storm, a behavioural ecologist now at the University of South Carolina Upstate, in Spartanburg, has shown that crickets manage to forewarn their offspring of lurking spiders, despite the small matter of never actually meeting them, reports New Scientist.
He briefly exposed lab-grown female crickets to wolf spiders whose fangs had been immobilised with wax, then studied the behaviour of their subsequent offspring.
The results showed that their offspring remained motionless for longer in the presence of spider silk or droppings than the offspring of mothers that had not been exposed to spiders. Staying still is one of the ways that crickets avoid becoming spider food.
Exposing the eggs or juvenile crickets themselves to spider cues did not alter their behaviour, suggesting the mothers had influenced this aspect of their young's behaviour during the egg's production.
The maternal heads-up was effective: "forewarned" crickets also knew to make use of a crack in their cage to hide from spiders. They survived three times longer in the presence of spiders than the offspring of naive mothers, on average.
Storm found that wild-caught crickets from spider-rich habitats also produce more cautious offspring than mothers from spider-poor habitat.
However, he doesn't know whether the mother's warning is transmitted to the egg via maternal hormones or some other mechanism.
The study has been published in American Naturalist.