I wonder how many children have foregone the school curriculum during lockdown in favour of lessons in nature exploration and specifically, caterpillar husbandry.
From talking to others, I know we are not the only household where any suitable container is intercepted before it gets to the recycling bin and turned into a comfortable abode for butterflies and moths during their often-overlooked larval phase.
Walks in the park are now spent inspecting the underside of foliage for lurking caterpillars or looking for the tell-tale signs of rolled up leaves held together with silk to form a protective bivouac. As gardeners will no doubt attest, once you start looking, the signs of decimated leaves are everywhere. Yet caterpillars themselves are far harder to find. I suspect a part of this is because I’m not the only one looking for them, and the competition is far better at it than me.
The downside of being a hungry caterpillar is that you yourself are an energy rich snack. Although a caterpillar may ultimately consume 27,000 times its own body weight, it still takes a lot of them to feed a growing Blue Tit chick. In fact, nest monitoring has shown that a single chick may consume up to 100 caterpillars a day. This could equate to as many as 20,000 caterpillars to fledge a single brood!
Of course, caterpillars don’t take this onslaught lying down (figuratively speaking). Defences include good old fashioned camouflage, being unpalatably hairy, aposematism (where they use bright colours to alert predators to their toxicity),
Batesian mimicry (where they pretend to look like something more dangerous than they are) and thanatosis (where they play dead and tumble to the ground and safety as soon as they are disturbed).