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Weekly Puzzler Answer 251

I know last week’s puzzler was WAY TOO HARD. We’ll do an easier one for this week. The green leaf shape in the vegetation is the chrysalis (also called the pupa) of a black swallowtail. The food plants of black swallowtail caterpillars are dill, fennel, rue, and Queen Anne’s lace. If you want to attract these to your yard, you could plant these or other plants in the carrot family. Here’s what the caterpillar looks like.

The caterpillar of a black swallowtail.
An eastern black swallowtail butterfly.

And here’s the chrysalis:

The green chrysalis from a black swallowtail.
A green chrysalis or pupa

Something I learned that I think is interesting about this is the color change. Sometimes the chrysalis is brown and sometimes it is green. Why the difference I wondered? When I went to do some research I found a blog by a retired Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010.) Of the chrysalis/pupa of black swallowtails, he says, “Caterpillars have photo receptors (stemmata) with pigments that presumably can detect the surrounding color when it starts to pupate. The color triggers or inhibits the release of a hormone that controls pupal coloration. High levels of hormone will produce a brown pupa, low levels produce a green pupa. Injection of caterpillars on a green background with a nerve extract from caterpillars that are on a brown background will produce brown pupae. Adjusting their color so they are harder to detect helps Black Swallowtail pupae avoid predation.”

Mother Nature gives animals so many amazing adaptations to better their chance for survival. Ready for another puzzler? Let’s stay with our small animals theme for a while. We’ll do a butterfly this time, one that is yellow and black, just like the stripes on the eastern black swallowtail. 

4 thoughts on “Weekly Puzzler Answer 251

  1. Nanci Fletcher says:

    a couple of years ago we found a brown one, kept it on the porch ..all winter. we gave up hope that it was viable. But a beautiful swallow tail unexpectedly emerged!

    1. Sharon Mammoser says:

      What a great surprise! Mother Nature never ceases to amaze us, right? Thanks for sharing.

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