How exciting! Another hidden gem of planet Earth has revealed itself to the world. The photographed caterpillar produced by photographer Marco Fischer depicts a Saturniidae caterpillar, the larval form of a moth from the Saturniids insect family. It’s been agreed upon that this majestic looking caterpillar doesn’t come anywhere close to looking like the average caterpillar you might find ravaging your garden vegetables.
Saturniids, the largest species of moth are found all around the world, specifically in tropical and sub-tropical regions, with the greatest diversity in the New World tropics and Mexico. However, this most interesting specimen was photographed in Switzerland.
Some saturniids produce more than once a year with the spring and summer broods hatching is just a matter of weeks, while autumn broods enter a state known as diapause and emerge the following spring. Diapause, most often observed in insects, is the delay in development due to adverse environmental conditions; a mechanism used as a means to survive unfavorable environmental conditions, such as extreme temperatures, drought, or reduced food availability. How the pupae know when to hatch early or hibernate is not completely understood yet, though it’s been suggested that the length of the day plays an important role.
Just like every other insect, saturniids go through a life cycle, and depending on the moth, a single female may lay up to 200 eggs on a chosen host plant. Others are laid singly or in small groups. The eggs are round, slightly flattened, smooth, and translucent color.
In larvae form (caterpillar), they can be large, up to 100mm, stout, and cylindrical. Most have tubercules that are often spiny or hairy, and some have stinging hairs. Those of the Lonomia genus contain a poison which may kill a human.
Most saturniids larvae feed on foliage of trees and shrubs, and some even eat grasses. They tend to moult four to six times before entering the pupal stage. Prior to pupation, a wandering stage occurs, and the caterpillar may change color, becoming more cryptic just before this stage.
Most larvae spin a silken cocoon in the leaves of a preferred host plant or in the leaf litter on the ground, or in crevices in rocks and logs. Interestingly, the cocoons of most larger saturniids can be gathered and used to make silk fabric. However, some species burrow and pupate in a small chamber beneath the soil making it harder to harvest. Besides, those that pupate underground do not use much silk in the construction process.
Adult saturniids females will emerge with a complete set of mature ova and “summon” males by emitting pheromones. Males can detect these chemical signals up to a mile away with help from sensitive receptors located on the tips of their feather-like antennae. The males will fly several miles in one night just to locate a female and mate with her.
Since the mouthparts of adult saturniids are vestigial and digestive tracts are absent, adult saturniids behavior is devoted entirely to reproduction but due to lack of feeding the end result is a lifespan of just a week or less once emerged from the pupa.