The Monarch Butterfly

I was looking back through the archives of this blog and was stunned to discover that I had never written a post about the ubiquitous Monarch butterfly. So now, in the dead of (Florida) winter when almost nothing is green I hereby declare this week to be milkweed week! Milkweed butterflies are hardy enough to survive even these cold months and their bright colors can warm even an entirely brown garden enough to give a gardener hope for Spring.

The Monarch butterfly (Danaus plexippus) starts life as a tiny white egg deposited on a Milkweed (Asclepias spp.) plant. The diminutive larvae develops inside the egg and eventually eats its way through the eggshell, quickly making its first home into its first meal.

Monarch caterpillars go through 5 instars or periods of growth between molting when the caterpillar will shed its skin. At each instar the caterpillar is usually at a particular range of size  and has certain characteristics. These changes in size and coloring allow us to figure out where they are in their development process and then know about how much they will need to eat. Monarch larvae are prolific eaters and can strip milkweed plants bare with remarkable speed.  Rearing monarchs can be a real challenge for this reason and also because they are susceptible to several diseases and many predators.

Once the Monarch larvae has reached its full size it will attach itself in a protected  place using a tiny pad of silk spun from organs called spinnerets. The larvae will slowly shed its skin revealing a green pupa beneath which is called a chrysalis. See video here. The chrysalis of the Monarch is a pale  green and feels waxy to the touch. Tiny spots and lines of iridescent gold mark the surface of the chrysalis making it a truly beautiful sight to behold. As the butterfly inside undergoes metamorphosis, the chrysalis skin begins to thin and become clear, revealing the developing butterfly inside. After about two weeks, the fully formed Monarch ecloses from the chrysalis and will be ready to fly in a few short hours.

The adult Monarch can live up to about a month and spends that time searching for a mate, feeding, or possibly ovipositing (laying eggs). The male Monarch can be distinguished from the female of the species by a raised black spot on the lower wing. This raised area is a pouch on the wing that produces scented scales called androconia that males use to help attract females.

Monarchs in peninsular Florida are non-migratory and have an established year-round population in the Tampa Bay area. Even right after the hard freezes a few weeks ago, Monarchs were out patrolling for food and mates. as soon as the weather warmed up.

Outside of Florida the Monarch is known as one of the best known migratory creatures of the animal kingdom with individuals travelling up to 3,000 miles so that they may overwinter in highlands of Mexico. This annual migration helps to keep the population safe over the winter but also serves to help keep the population more disease free as sick individuals are less likely to be able to make the whole journey. Each Spring these monarchs mate and then begin flying further north with each successive generation.

The Monarch butterfly is a member of the Nymphalidae or brush-foot family. The adult butterfly only appears to have 4 legs as the last 2 insect legs are very small and are located near the butterfly's head. As adults, these butterflies are clever mimics utilizing Mullarian mimicry to reinforce the warning colors and distasteful qualities of several related species, gaining all three species more protection from predators.

Photo credit: Mirrored monarchs photo by Jill Staake