Why fireflies light up the night - JuniperCivic.com
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Originally published in the June 2019 Juniper Berry Magazine

Why fireflies light up the night

My birthday is at the end of June and when I was a kid there were 2 things my brain associated that special day with ‒ the end of the school year and the beginning of firefly season.

Fireflies are usually one of the first natural phenomena to excite children. While playing outside at dusk, they become mesmerized by tiny mobile flashes of light. Many a child has captured lightning bugs in a jar to watch the spectacle up close.

What is not usually apparent to kids is that the fireflies are flashing to attract mates. They do this via a process called bioluminescence, where light energy is produced via a chemical reaction. Different species use this in different ways – in one species, females emit light from their abdomens to attract males; in the other, flying males emit signals to which the females respond.

There are more than 2,000 species of fireflies worldwide and they are found on every continent except Antarctica. In the United States, there are no fireflies west of the Rocky Mountains. The most common species in New York City is the Big Dipper Firefly; the males of this species light up our yards and parks at night in search of receptive females who emit dimmer signals in return.

Although we call them fireflies or lightning bugs, in reality, they are members of the beetle family. Their larvae, which also flash, are alternatively known as glowworms. They live underground from 1-2 years before maturing. Larvae thrive in moisture, and after the rainy spring we had, they are likely to be out in good numbers this year. They mainly feed on pill bugs, snails and slugs, so if your yard has an abundance of these crawlers, it will also likely host many fireflies. Keeping pesticide use to a minimum will also help bring more fireflies to your property.

Interestingly, adult fireflies, if they do eat, stick to nectar and pollen, but because their lifespan is so short, some do not eat at all! Once they reach adulthood, the firefly lifespan is only 3-4 weeks, which is why their numbers noticeably dwindle by mid-July. So, enjoy them while you can, because they'll soon be gone ‒ in a flash!

June 2019 Juniper Berry Magazine

June 2019 Table of Contents