Even though most spiders are harmless to us, many people suffer from a crippling fear of them. Imagine then, what a grasshopper must feel. The threat of venomous fangs isn’t something that the insects can shrug off. It’s a perpetual danger that chemically alters their bodies, triggering changes that ripple through an entire ecosystem.

Now, Dror Hawlena from Yale University has found just how far-reaching these changes can be. In an elegant experiment, he showed that the fear instilled by spiders can extend into the very soil, affecting how quickly leaf litter decays.

Hawlena raised red-legged grasshoppers in outdoor enclosures, half a metre wide. Half the enclosures contained a single nursery-web spider, whose mouthparts had been glued shut, so they