Firefly or lightening bug — what do you call the insects that put on a nightly light show during the summer? Most of the people that attended the July 12 “Who Doesn’t Love Fireflies?” program call them lightening bugs.
Contrary to their common name, fireflies are not flies nor are they true bugs, they are beetles. Also, there is no fire or lightning involved in the glow these insects display. Program presenter, Ariel Firebaugh of Blandy Experimental Farm, told us the light produced by fireflies is the result of a chemical reaction that takes place within the insect’s abdomen. The chemical is luciferase and people use it to detect the presence of bacteria. Prior to the 1980s, we were not able to produce luciferase in a lab so lightening bugs were the only source.
Other interesting things we learned from Ariel included:
- There are 2000 species of fireflies worldwide, 150 species in North America and Virginia is home to 20 species of fireflies.
- In the United States, fireflies live east of the Mississippi River with a few random patches of them in the western states.
- These insects light up to attract mates and each species has its own flash pattern. The Common Eastern Firefly flashes in a J-like pattern while the Predator Firefly flashes quickly like a laser gun.
- During the day, they hang out in cool shady places like the underside of leaves.
- There are species of fireflies that are active during the day. Rather than flashing light to attract a mate, they have pheromones.
- Lightening bugs live in the larval stage for one to two years and, as adults, only live for two months.
- Adults do not eat, but in the larval stage they are fierce predators that have venom they inject into worms, grubs, and snails.
- Larval stage fireflies live in areas of really moist soil (like near creeks) and can be seen on the ground in fall due to their faint glow. They overwinter in leaf litter and around fallen logs.
- Lightening bug predators include: frogs, mice, raccoons, and spiders. The have a bad taste, and when eaten, the chemicals in fireflies can affect the predators heart muscles.
- Fireflies, Glow-worms and Lightening Bugs by Lynn Faust is the only field guide for identifying fireflies.
- There are only 100 firefly scientists worldwide so there is a lot that is unknown. Populations may be decreasing due to:
- Landscape practices like mowing, pesticide use, and removal of leaves and fallen trees and branches
- Habitat destruction of low-lying moist areas
- Light pollution may hinder reproduction because some fireflies stop flashing
- We can help scientist through the Firefly Watch Community Science Projects
Ariel Firebaugh’s “Who Doesn’t Love Fireflies?” Program was a fun, interactive program for adults and kids alike, especially when we drew what we thought lightening bug larvae looked like (before seeing what they really looked like) and learned a lot about them. We finished the program by heading into the lawn area of the mansion at Morven Park to catch and release lightening bugs.