Читать книгу Extreme Insects - Richard Jones - Страница 25

NAME	bloody-nosed beetle Timarcha tenebricosa
LOCATION	Europe and Central Asia
ABILITY	deliberately spits out its own blood

Insects defend themselves from attack in many different ways. After hiding, possessing a weapon is one of the commonest strategies. The weapon may be biting or stinging an enemy, but it may also be simply tasting foul. Plenty of plants contain noxious chemicals to deter herbivores, and plant-feeding insects can take advantage of this fact by storing the poisons in their bodies.

There is one drawback for the individual with the poisonous body. Although birds (the main insect predators) may soon learn to avoid a particular species because it tastes disgusting, that is a bit late for the individual insect they have picked up, crushed, chewed and swallowed, even if they then vomit it back up again. It would be much better if the insect could warn of fits potential predator by giving it a taste of what might come should the meal be fully consumed.

This is exactly what many beetles do. Rather than wait until their innards are squashed out in the bird’s beak, they defensively squeeze out large droplets of their foul-tasting haemolymph (blood). As soon as the bird tastes the bitter chemicals, it spits out the not-so-tasty morsel more or less unharmed.

The commonest beetles to use this defence, called reflex bleeding, are ladybirds, which exude droplets of their yellow body fluids from special pores in their knee joints. The most spectacular, though, is the aptly named bloody-nosed beetle, Timarcha tenebricosa, which oozes out a great drop of bright-red liquor from its mouthparts.

Ladybirds are brightly coloured to emphasise the warning. Timarcha is a sombre black, but its colouring is equally obvious against the green of its meadow foodplants. This large, lumbering flightless leaf beetle has little to fear from predators and it feeds quite happily in broad daylight.