What are fireflies? Maybe you call them fireflies or maybe you call them lightning bugs, but these insects are actually beetles, just like ladybugs. Like all beetles, a firefly’s life cycle has four stages: egg, larva, pupa, and adult. Adult females will lay their eggs in mid-summer in the ground, preferably in moist places near ponds and streams and in leaf litter. After about 3 weeks, larvae emerge. After a year or two as a larva, the firefly will go underground for about 3 weeks. In Maryland, adult fireflies only emerge in late June to early July, spending 3-4 weeks attracting potential mates. Most adult fireflies can reach up to one inch in length, but the biggest fireflies are huge. Females of the Lamprigera firefly can grow to be the size of your palm.
Why do fireflies glow? The larva and adult fireflies produce a chemical reaction inside their bodies that allows them to light up to attract mates and ward off predators. This type of light production is called bioluminescence. Each species has its own pattern—a code that lets individuals find mates.
What can we do to help fireflies? There are more than 2,000 species of fireflies worldwide but only six species found in Maryland. The most common fireflies we see are the Eastern firefly, the black firefly, and the winter firefly. Firefly numbers are declining globally due to habitat loss, pesticide use, and light pollution. But there are ways that you can help the fireflies:
· Turn off outside lights at night: Human light pollution can disrupt the glowing and flashes, making it harder for fireflies to find mates and breed.
· Create water features in your yard: Fireflies love standing water and marshy areas where the soil is soft and moist.
· Avoid using pesticides or herbicides on your property: Pesticides and herbicides may kill adults and larvae.
· Do not over-mow your lawn: While it looks nice to mow your grass short, fireflies like to rest in long grasses during the day.
You can also help track fireflies by participating in the Firefly Watch Community Project! All you need to do is spend 10 minutes once a week observing fireflies in one location. Charlotte’s Quest would be a great spot to track fireflies. More information is available here:
Is it safe to catch fireflies? Many of us have childhood memories of catching fireflies and keeping them in jars. We can all still safely catch fireflies if we treat them gently and release them into the wild. If you want to catch fireflies the Firefly Conservation & Research organization provides these tips:
1) Turn off exterior lights
2) Mimic a firefly by using a flashlight
3) Catch fireflies with a net
4) Place fireflies in a clear jar with a pierced lid and a damp unbleached coffee filter inside to keep the air in the jar humid
5) Fireflies will readily drink the juice from a fresh apple, so keep an apple slice in your jar.
6) Don’t keep fireflies for longer than a day or two. Let them go at night because that’s when they’re most active and able to avoid predators.
You can find more guidance on how to catch fireflies online here: