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 couldn’t actually kill any of the hoppers. Their
presence, however, was felt. From past studies, we know that
prey animals build up stress hormones and experience higher
metabolic rates when predators are around. This soaks up a lot
of energy, so stressed animals