Caterpillars more likely to vomit alone

A type of caterpillar which defends itself by regurgitating on its predators is less likely to do so when in groups than when alone, a new study by researchers from the University of Liverpool and the University of Bristol has found. Such reluctance is sufficient to cancel out the benefits of being in a group. The study, published in Ecology Letters, will help in the design of more sustainable methods for reducing crop losses caused by caterpillars and similar pests. Animals have some unusual ways to defend themselves against enemies. While many rely on nasty stings and dangerous venoms, the caterpillars of the large white butterfly ( Pieris brassicae ) protect themselves by vomiting on their predators. These caterpillars, like many other species that have anti-predator defences, live in groups so that they have safety in numbers. However, many studies have shown that the size of a group does not affect the chance of survival in several different species.