I seldom get pairings with males in the cages. Once paired, the couple tend to stay paired until the following evening. A single mating will fertilize all of the 200-350 eggs. Males may mate again, but ova may not be viable. Sperm in the female receptacles triggers ovulation responses, but even unmated females begin laying eggs after two or three evenings.
Incubation lasts ten to fourteen days.
Emerging caterpillars chew through one side of the the egg. Photos by David Wilbur. The larvae eat most of their eggshells and spend six to eight weeks passing through five instars as green caterpillars. The large brown heads, typical of polyphemus larvae, are evident even in the first instar. Larvae stop feeding and become quiescent for a day or two before shedding skins to make way for new growth.