Pieris rapae rapae

Cabbage White

This Eurasian/N. African immigrant arrived in the United States in the 1860s and is now an established resident even in New Zealand. It can fly year-round, weather permitting, using mustard-family plants including garden varieties. The mustard oils make the adult butterfly distasteful to birds, while the larvae have a fluid on their setae (little hairs) that repels ants. But they are actually quite an attractive, graceful butterfly. Perhaps the lack of gaudy decoration is meant to call attention to the classic shape of the wings.

Female Pieris rapae - Cabbage White
Pieris rapae nectaring in the garden. April 18, 2014.
Female Pieris rapae - Cabbage White
Females have two black dots on the forewing; males just one. La Jolla Canyon in the Santa Monica Mountains, January 12, 2006.
Male Pieris rapae - Cabbage White
Male Pieris rapae in San Gabriel Canyon. March 8, 2006.
Male Pieris rapae - Cabbage White
Some are more yellow than others on the underside; I believe this is due to uric acid. In my garden in Long Beach, October 25, 2005.
Egg of Pieris rapae - Cabbage White
Pieris rapae eggs, the one on the left freshly laid. Both are on nasturtiums, which is a good larval host.
Larva of Pieris rapae - Cabbage White caterpillar
Larva of Pieris rapae on a nasturtium plant in my garden. March 23, 2009.
Larva of Pieris rapae - Cabbage White caterpillar
Up close, you can see the yellow mid-dorsal line, yellow dots along the side, small black spots, and the setae that have a repellent fluid. The white ocelli are ringed in black. Same larva as above.
Larva of Pieris rapae - Cabbage White caterpillar
Late in the year - or early - you can still find Pieris rapae while out for a stroll on a nice day. Another female, this one at the El Dorado Park Nature Center in Long Beach. October 20, 2005.
Larva of Pieris rapae - Cabbage White caterpillar
This butterfly was named by Carl Linnaeus himself. Here's what the reference looks like. It's from the landmark 10th Edition of the Systema Naturae of 1758. The species Rapae was the 59th to be named under the genus Papilio. Linnaeus included subgeneric groups under Papilio; rapae was with the "Danai candidi" group.
Larva of Pieris rapae - Cabbage White caterpillar
So when did Papilio rapae become Pieris rapae? In 1801, Franz von Paula Schrank's Fauna Boica was published in Ingolstadt, Germany. Here we find a new genus: Pieris. In 1836, Boisduval used Pieris for a subset of the species Schrank had used it for, including rapae, and his treatment was widely adopted.
Larva of Pieris rapae - Cabbage White caterpillar
These labels are with the lectotype.
As noted above, Rapae was the 59th species of Papilio in Linnaeus' tome.
Permission of The Linnean Society of London.

©Dennis Walker