Will the Baltimore checkerspot stay in Baltimore?

What’s black and orange and flies all over? It’s not a monarch—although it does have a royal name. Named after George Calvert, the first Lord Baltimore, the Baltimore checkerspot (Euphydryas phaeton) is a symbol of pride for Baltimore and the entire Chesapeake Bay region. It was even named the official insect of Maryland in 1973 and was once seen flying all over the state.

However, recent monitoring has revealed that Baltimore checkerspots can only be found in less than eleven sites over seven Maryland counties. The Maryland Department of Natural Resources lists the butterfly as rare, which means that the population is vulnerable to becoming extinct in the state. This recent vulnerability is due, in part, to climate change.

One of the impacts of climate change has been a shift of temperature and rain patterns, which can directly affect the environment in which Baltimore checkerspots live and grow. For example, the Chesapeake Bay region has been experiencing warmer and shorter winters. This causes the host plant of the Baltimore checkerspot, the white turtlehead, to bloom earlier, before the caterpillars hatch. Baltimore checkerspots lay their eggs exclusively on white turtleheads and the caterpillars feed mainly from the flower’s nectar. If these flowers bloom earlier, it could cut off Baltimore checkerspots from finding a place to lay their eggs and the young from obtaining the nutrients they need.

A unique aspect of the Baltimore checkerspot life cycle is that the caterpillars hibernate over the winter. After hatching from their eggs, Baltimore checkerspot caterpillars spend the fall eating, growing and molting, before hibernating under dead leaves and grass on the ground. This leaves them vulnerable to extreme changes in winter weather, like the occurrence of heat-waves and warmer days caused by climate change. A recent study by Georgetown University found that Baltimore checkerspot caterpillars exposed to winter heat waves resulted in a 75 to 100 percent mortality rate. The number and severity of these heat waves and warm winter days has increased in the last century, heightening the risk of exposure for Baltimore checkerspots.

What does this mean for the Baltimore checkerspot? It means that Maryland’s official insect might not be able to survive in its home state for much longer. Sites that previously housed Baltimore checkerspot populations are no longer viable, with only a few sites remaining, mostly in the western part of the state.

Luckily, there is something we can do to help these beautiful butterflies: plant our own butterfly gardens. By planting more white turtleheads, we can help supply these vulnerable butterflies with nectar and places to lay their eggs. The Maryland Department of Natural Resource’s Baltimore Checkerspot Recovery Team lists more ways you can help restore the Baltimore checkerspot.