Cinnabar caterpillar eating ragwort

Description:

Black-and-gold striped caterpillars.

Habitat:

These were found eating ragwort in my front garden. Ragwort, a toxic and unpalatable plant, is not only the primary food source for these caterpillars but also provides them with a defence mechanism: these little guys are not affected by the toxins in the plant, but actually become toxic themselves by eating the plant. Their colourful stripes serve as a warming to potential predators that they taste awful and are toxic.

Notes:

Newly-hatched caterpillars cluster together at the base of the plant and work their way up as they grow bigger and develop their toxic defence. These caterpillars can decimate whole patches of ragwort, leaving many caterpillars starving - this increases competition and the caterpillars become more aggressive as they grow and can also become cannibals when starved. The caterpillars take a month to fully develop. They then descend the plant where they will make cocoons, ready for the metamorphosis into beautiful black and red adult moths.