ScienceShot: Ladybugs as Bodyguards

This ladybug may look like she's protecting her brood. But the cocoon perched between her legs is actually a parasite taking advantage of a safe space to grow. The parasitic wasp Dinocampus coccinellae is known to lay its eggs in the circulatory system of ladybugs, where larvae feed on ladybug tissues before pushing out of her abdomen. Then, the developing parasite spins a cocoon between the ladybug's legs. A new study, appearing online today in the Journal of the Royal Society Biology Letters, explains why the parasite doesn't kill the ladybug during this whole process. When scientists setup an artificial ecosystem in the lab, complete with ladybugs, parasites, and lacewings, insects that like to make a meal of wasp cocoons, they found that when the cocoons were between the legs of a living ladybug, only 35% were killed by predators, compared with 85% if the cocoon was attached to a dead ladybug, and nearly 100% if it was free from any ladybug. So the ladybug above may not be protecting her offspring—but she is protecting herself.

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