Chrysalis

The remains of a pupa, or chrysalis. This was, I think, the temporary home of a specimen of a Monarch, Danaus plexippus, as it underwent metamorphosis from caterpillar to butterfly. The caterpillars themselves were much in evidence here in Brooklyn Bridge Park at the end of August, gobbling up milkweed.

Curiously, the milkweeds contains noxious chemicals that repeal some predators, but Monarch caterpillars are unaffected by them. The chemicals remain in the insects’ bodies through metamorphosis, making the adults unpalatable to predators. Birds learn very quickly that Monarchs taste awful. The bold showiness of both caterpillar and butterfly is an announcement of threat. An unrelated butterfly species, the Viceroy (Limenitis archippus), mimics the Monarch’s appearance to capitalize on this.