The Summer of the Firefly

There are around two-thousand species of fireflies worldwide

Friday, July 26, 2013, 7:55 PM -

There's nothing like that unexpected moment. Something catches your peripheral vision, a brief light in the still night air as crickets chorus endlessly. A firefly blinks momentarily, giving only a hint as to where it's flying. They're not only fun to watch, but a challenge to catch, bioluminescence on the wing. 

There's been no shortage of rain is southern Ontario this summer. Gardens and meadows are lush, lending themselves to what fireflies like most, a habitat luxuriant with trees and tall grasses. 

There are more than 120 species in North America. Each has its own distinctive sequence used by the male to attract a mate, like visual morse code in the dark. Fireflies also use their cold light to attract prey and discourage predators. It's produced by the chemical reaction between two compounds, a substrate Luciferin and Luciferase, an enzyme. Oxygen keeps the reaction going. One theory suggests the insect can control that reaction by adjusting the oxygen supply to its abdomen. 

Fireflies belong to a family of beetles called lampyridae, they're typically active from late June through early August. There are around two thousand species worldwide. Most give off a yellow or green light, but some glow red. The intensity of the light varies from one species to the next. Cyphonocerus ruficollis is an Asian species with a weak glow. 

Despite it being a relatively good summer for fireflies in North America, many species are under threat from human encroachment on habitat, and light pollution from cities and traffic. You can help bolster local populations by turning off outdoor lights, planting trees and long grasses on your property, and avoiding the use of pesticides.