urbpan | 365 Urban Species. #199: Monarch

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urbpan. Location: Olmsted Park, Boston.

Urban species #199: Monarch Danaus plexippus

Of the dozen or so species of migratory butterflies in North America, the monarch is certainly the most well-known and popular. Seven states claim it as the official State Insect, second only to the introduced European honeybee (12 states). It is an uncommonly beautiful insect, even by mainstream tastes. Its bright orange and black colors reminded the colonists of royalty, though they exist to remind birds that they taste bad. Several species of butterfly have bold colors to warn predators away, and some more palatable butterflies have the same bold colors in imitation of the bad tasting ones. Toxic compounds acquired from their exclusive diet of milkweed, as larvae, give both monarch caterpillars and adults their protective taste. There are many species of milkweeds available to them, including many weedy urban species, and many planted by gardeners who wish to attract butterflies. There exists at least one milkweed, black swallow-wort, that monarchs will lay eggs on, but that the caterpillars are unable to feed on. Fortunately, the adult lays a single egg on each individual plant so there are many chances for the correct plant to be chosen. Currently, the greatest threat to monarchs is the loss of trees in their wintering grounds in California, the American south, and Mexico.

Location: Drumlin Farm.

Flat | Top-Level Comments Only

They have six true legs, all on the first three segments behind the head (what will become the adult thorax)

On their abdomen, they may have up to five pairs of prolegs. These aren't really propper legs - just little fleshy protrusions with hooks (called crochets) on the end to help them grip their substrate.

lol @ your icon!

to us ignorant types, those nubs are leggy enough to be legs.

well, they don't have any joints. Prolegs are more like...butt cheeks with permanent velcro.

butt cheeks with permanent velcro

The things I missed not studying entomology in college.

oh, that's horrible.

Ah, thank you professor, I was still in the research phase of that answer when you got to it.

But I did just learn that some butterflies lose one pair of true legs when they metamorphose (?!) (scroll to bottom of linked page for illustrated species)

Yup, there are four families of butterflies that have significantly reduced front legs: Nymphalidae (the brush-footed butterflies), Danaidae (milkweed butterflies), Satyridae (satyrs & wood nymphs) and Libytheidae (snout butterflies). It's unclear what evolutionary advantage this limb reduction serves.

365 Urban Species. #199: Monarch

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