The discovery of this caterpillar on a Nothofagus antarctica (southern beech) tree in the alpine garden yesterday provoked some excitement among the staff (and a comment that it has good taste in trees). Eight centimetres long and as thick as my forefinger, this caterpillar is the larval stage for the polyphemus moth. Leaves of deciduous hardwood trees and shrubs form the diet of this caterpillar. It has been observed that the caterpillar cuts the petiole of leaves it has skeletonized, so that (purportedly) no traces of its presence remain on the tree to alert predators.
Antheraea polyphemus belongs to the subfamily of moths known as the saturnids (Saturniidae), or giant silk moths. The Saturniidae, it can be argued, are the most striking of moths. Photographs of moths in this subfamily can be seen here: Saturniidae Moths from Thailand and the What’s That Bug? postings on saturnids.
This entry was Botany Photo of the Day’s contribution to the first-ever Circus of the Spineless, a monthly gathering of online essays and photographs about invertebrates.
Entomology / Botany resource link: Lepidoptera of the Pacific Northwest: Caterpillars and Adults. The life cycles of plants and insects are often intertwined, so knowledge of insects can give depth to understanding of plants; this link provides details on caterpillar morphology and ecology, as well as many photographs.