White Peacocks and an Explorer Scientist

They have finally returned! I posted back in August about the complete absence of a normally common butterfly: The White Peacock. Normally common on the MOSI campus, this species had been unobserved here this season after the dramatic cold of last winter. As of this week, they have returned. Two individuals were spotted in the MOSI gardens this week so we are hopeful that a resident population will be soon to follow.

Found throughout the Southern United States, the White Peacock Butterfly (Anartia jatrophaeis) a fast and erratic flying tropical butterfly. Adults of this species can often be found in open weedy areas, especially those near to retention ponds or waterways where the host plants become abundant. It is not uncommon to find small populations of this butterfly cruising the margins of a pond, all quite happy to live their whole life cycle out around that singular source of water and larval food. Males are very territorial and will fly off any intruders that happen into their several square feet of territory.

Females deposit their tiny green eggs on the undersides of larval hosts like Water Hyssop (Bacopa monnieri). The caterpillars are a dark charcoal grey to black in color with tiny dots of silvery white and are covered in branching spines. When threatened by a predator (or a keeper trying to move them to fresh food) the caterpillars arch sharply backward and often throw themselves from their host plant. If they land on muddy ground they are nearly impossible to see. If they land on water the branching spines on the larvae help them to float. The caterpillars will ride along the surface of the water until they can climb out on a bit of plant or at the water's edge.

The chrysalis are either bright green or black in color and blend almost perfectly into their surroundings. The pupae are sometimes made very close to the ground so at the adult butterflies emerge they may have to climb to a higher vantage point to begin pumping fluids through the veins in their wings, bringing their wings to full size.

A little history and and incredible scientist: The species was first described in 1763 by Carl Linnaeus as Papilio jatrophae. Linnaeus cites a 1705 illustration by Maria Sibylla Merian (1647-1717) of the various life stages of the species. Maria Sibylla was a German scientific illustrator and naturalist who directly observed the lives of insects and gathered evidence to contradict the popular ‘modern’ theory that insects were “born of mud” through spontaneous genesis. Through observation and careful recording of data, Maria Sibylla helped people to understand the process of metamorphosis.

Maria Sibylla traveled to Suriname in 1699 to collect insects and some of her engravings can be seen here. Her scientific endeavors and travels in South America were sponsored by the city of Amsterdam in which her scientific observations had gained her much renown. After two years of travels, Maria Sibylla was forced to return to Amsterdam due to malaria. Her observations and engravings from Suriname were published in Metamorphosis insectorum surinamensium (Transformations of the insects of Surinam). The White Peacock butterfly is resident in sub-tropical North America but can also be found throughout Central and portions of South America.