mass movement of the larvae of Sawflies (Perreyia sp.), Ilha Grande, Rio de Janeiro, Brazil
These “caterpillars” are the larvae of Sawflies, which are in the insect orderHymenoptera (which also includes ants, wasps, and bees). The larvae of some species in this genus sometimes moves along the forest floor as a mass, feeding on fallen leaves. It is not well understood why they do this. They are found in a few countries in the Amazon Basin of South America.
The bees, wasps and ants belong to the Hymenoptera. Hymenoptera means ‘married wings,’ as the hind wings are coupled to the front wings by a line of hooks. This is undoubtedly the most beneficial order of insects and many members are pollinators or important predators or parasitoids of other insects. Hymenopterans have complete metamorphosis illustrated by a sawfly larva and an adult pictured above. Within this group the bees, wasps and ants have characteristic pinched waists, while the sawflies do not. They have chewing mouthparts, but some also have lapping mouthparts (in addition to chewing) for nectar feeding.