My garden recently has had a huge influx of monarch caterpillars. We usually have caterpillars throughout the year, but they seemed to have taken a break this year, as I did not begin to find them again until last month.
There are four stages in the life cycle of a monarch butterfly: the egg, the larvae (caterpillar) the pupa (chrysalis) and the butterfly. I have a few caterpillars left still chomping away from the influx, with more than two dozen chrysalis.
After the butterfly lays a cream colored egg on the bottom of a milkweed leaf, it takes anywhere from three to five days to hatch. The larvae chews a small hole in the egg to wiggle free. Once it emerges it consumes the rest of the egg before moving onto the leaf.
According to “Florida Butterfly Caterpillars and Their Host Plant” (Marc C. Minno, Jerry F. Butler and Donald W. Hall), the milkweed plant has latex within that sticks to the mouthparts of herbivores. The caterpillars will cut the leaves near the base of the milkweed blade to drain out that latex before they begin eating.
As the yellow, black and white stripped caterpillar eats the milkweed leaf it continues to grow and molts its old skin, splitting it in half. The caterpillar often consumes the skin before continuing eating the milkweed leaf. It can grow in length to 2″.
The caterpillar will molt four times, going through “instars” before its last molt.
Once they reach two inches they are ready for their pupa stage. The caterpillar finds the perfect destination to form its chrysalis and weaves a silk mat. The caterpillar grabs the silk with its legs to hang upside down in the “J” form, according to Arizona State University School of Life Sciences.
