Pine Processionary Moth

Sibling group of pine processionary caterpillars moving in their characteristic mode forming long head-to-tail processions.
The pine processionary caterpillar is the best known of all the processionaries, studied as early as 1736 by Raumier and later by Fabre (1898) whose essay “ The life of the caterpillar” is among the classics of popular entomological literature. The insect is found in the warmer regions of southern Europe, the Near East, and North Africa. It is the habit of the caterpillars to move over the ground in long head-to-tail processions and to sting with urticating hairs anyone who attempts to molest them that has brought the caterpillars to the attention of the public. It is also one of the most destructive of forest insects, capable of defoliating vast tracts of pines during its episodic population surges. Of interest here, however, is the fact that is among the most social of caterpillars. Sibling groups stay together throughout the larvae stage, often pupating side by side at sites they reach by forming long, over-the-gound, head-to-tail processions.
The insect is active only during the colder times of the year, spending the warm summer months as a pupa buried in the ground. The moths begin to emerge from the soil in August and shortly thereafter mate and seek out pine trees where they place their eggs. Each female produces a single egg mass which it fastens to a needle of a suitable host trees. Egg masses contain up to 300 or so eggs and the caterpillars typically eclose from them four or more weeks after they are laid. The eggs are completely covered with scales that detach from the abdomen of the female.