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• There are about 150’000 caterpillar species worldwide, up to 4’000 of them in Central Europe.
• Caterpillars only eat the leaves of the host plant. Their appetite is so great that they eat entire plants bare in a very short time.
• In some butterflies, the caterpillar stage is the only feeding phase. Butterflies of this species can only reproduce and die shortly after hatching. As the body size of the caterpillars increases greatly, they have to moult several times until they reach their final size.
• Similar to other insects with a complete metamorphosis, the caterpillar of the butterfly consists of evenly arranged segments that form its body. Of the typical 14 segments of the butterfly caterpillar, the last three are fused together. Like moths, caterpillars can also be divided into three sections: Head, thorax and abdomen. The head is usually hardened by chitinous deposits. On the outside of the underside they typically have six dot eyes (stemmata) each. The most important feature, which also determines the appearance of the head, are the mouthparts. Compared to the stubby antennae, they are very easy to recognise.
• Most caterpillars lead a hidden life and camouflage themselves in their environment. They are therefore usually green or brown.
• Caterpillars that live on conifers typically have longitudinal patterns, so they are particularly well camouflaged.
• Venomous animals, such as many species of bear moth (Arctiidae), warn predators with conspicuous colours. These caterpillars do not need to hide on their feeding plants. Other non-poisonous caterpillars with similar colouring (mimicry) benefit from this. Particularly conspicuous and unusual looking are the gypsy moths (Lymantriidae).
• The hawkmoth caterpillars are among the largest caterpillars in Europe. They can reach a length of 15cm. They have two eyespots and can imitate small snakes by their posture. This defence strategy is very effective. In addition, their colouration is such that when they hang upside down on a branch, their outline looks flat like leaves.
• Other caterpillars, such as peepers (Geometridae) are clinging motionless to branches and look like branches themselves. They even form bud-like thickenings.
• In some species, one can even observe social behaviour. For example, processionary moths (Thaumetopoeidae) live together in a large group and move in a long compact column to their next food. This camouflage prevents predators from recognising a single caterpillar.