If you can hear or see no weevils, it may be because the small, leaf-eating beetles with elbow-shaped antennae are hiding out in a caterpillar’s house. The invasive Asiatic oak weevil (Cyrtepistomus castaneus, pictured) finds a home away from home inside leaf sandwiches—called leaf ties—that some native caterpillars bind together for a nest. Researchers had thought that weevils fed on only the best leaves, but then noticed them congregating inside leaf ties. To investigate, they fastened two leaves together with a metal hair clip to make artificial ties in six tree species in Cuivre River State Park in Missouri. After several weeks, tied leaves harbored three-and-a-half times as many weevils as single ones across all six species, researchers report online this month in Ecology. They claim that this is the first report of native species inadvertently helping out an invader by creating a shelter from predators and the elements.

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