A Blizzard of Butterflies

How lovely to go for a walk accompanied by a magical fluttering of yellowish-white butterflies. It is enough to make anyone feel like a Disney princess, or like Bambi exploring a technicolor forest.

In other years there have sometimes been sudden butterfly hatchings, but I have never seen so many, or for so long. It seems that when the heavy November rains broke our six month drought and trees were able to grow new leaves, that in turn created unusually favorable conditions for butterfly eggs to develop into caterpillars that could grow and thrive and produce an abundance of butterflies.     

Cluster of Great Southern White butterflies in Fish Bay  Photo Gail Karlsson
 Although there are several similar types of butterflies around, the ones I have been seeing the most are Great Southern Whites. You can tell because they have distinctive turquoise tips on their antennas. 

Close-up of Great Southern White on a branch
Photo Gail Karlsson

The Great Southern Whites are not special to the Virgin Islands. They are also common throughout the southern United States, South America and the Caribbean. Other Caribbean islands have reported mass hatchings this season as well.   

In the Virgin Islands, the Great Southern Whites tend to use the numerous, local limber caper trees as hosts. The females attach clusters of about 20 tiny torpedo-shaped eggs to the leaves of the tree – potentially producing up to 500 eggs each. When conditions are right, the eggs develop into caterpillars with black spots, dark hairs, and yellow stripes running lengthwise along their backs - much smaller than the well-known frangipani caterpillar. After two or three weeks of feeding on leaves, the caterpillar will transform into a chrysalis with a hard shell, usually hanging inconspicuously on the tree. After a week or so the chrysalis bursts open and the butterfly emerges. All in all, it is an amazingly complex process.   

Butterflies mostly suck nectar from flowers, using a long proboscis that they can extend and insert into the flowers. They are important pollinators for many plants, transferring pollen from one flower to another as they flit about.

The Great Southern Whites also seem to be social drinkers. I have often seen them gathering in groups along on our dirt road, apparently getting together to drink and draw minerals from the wet spots – an activity known as ‘puddling’.
Great Southern Whites puddling in the dirt road
Photo Gail Karlsson

Unfortunately these butterflies have a short life span. While they are here, they bring great joy to people on St. John, and we can hope for another big batch of them again – if all the eggs these ones lay are able to hatch, and there are enough leaves for the hungry caterpillars to eat, as well as nectar-filled flowers for the next generation of emerging butterflies.