Backyard and Beyond

An unusually dark Monarch caterpillar found at that little wonderland of wildness, Brooklyn Bridge Park. The place was full of standard-colored Monarchs about two weeks earlier. This one was the only one seen on a more recent visit. It’s late, but probably not too late. Nearby, I found the remains of a pupa.

Also found on the milkweeds were these tiny orange things.

I wondered at first if they might be eggs. But they moved. They are milkweed aphids, also known as oelander aphids, Aphis nerii.

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.

A passel of monarch butterfly caterpillars, Danaus plexippus, were denuding some milkweed around the waterworks at the Brooklyn Bridge Park recently.

The monarch is probably our most familiar butterfly. The generation we see here may be the one that, come winged adulthood, makes the epic long march of a flight towards the cool cloud forests of central Mexico. For the next couple of weeks, you’ll see the adults along our coasts, being butted about by the winds, getting ready to go. Will you wonder, like me, how, how, how will they ever make it that far?