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APHIDS and caterpillars both like to eat broccoli. Aphids suck the plant’s juices, and caterpillars chew the leaves, but they are still competing to extract the most nutrients. Surprisingly, though, caterpillars can benefit aphids.
Carmen Blubaugh at Clemson University in South Carolina found that when caterpillars also snack on plants infested by aphids, the number of parasitoid wasps that attack the aphids decreases (Ecology, doi.org/ck8v). “The plant uses a different toolkit to defend against a caterpillar,” she says. When set on by aphids, the plant produces chemicals to attract wasps that parasitise the aphid – but if caterpillars join in, the …