Go native! Native plants benefit birds, bees, and butterflies

What is more magical than catching fireflies on a warm summer night? This treasured childhood memory is becoming more and more elusive as this humble beetle’s numbers decline worldwide, due to habitat loss, light pollution, and pesticide use.

There are many ways to welcome them to your own backyard and ensure that they will continue to delight children of all ages! Of the 120 species of firefly in Ohio, the Common Eastern Firefly (Photinus pyralis) is the one most of us will find in our backyards.

Firefly adults live 3-4 weeks; eggs take about 3 weeks to hatch, but the larvae live spend 1-2 years as larvae, hibernating underground or under tree bark. The pupae take another 3 weeks to mature. Because of this long period as larvae, the use of insecticides on lawns and landscaping can have long lasting effects on the firefly population.

Many firefly larvae, like this one, also produce light!

Don’t spray broad spectrum pesticides or use lawn chemicals! Mosquito spraying can not only kill adult fireflies directly (since they are most active when this spraying is commonly done), but sprays and lawn treatments can kill them by poisoning the insects the larvae pray upon. Neonicotinoid insecticides, that persist in the soil for years, are a danger to firefly larvae and their food supply.
Provide hiding spots (don’t over-mow) – long grasses, leaf litter and rotting logs in your yard will give the larvae places to complete their life cycle. Even a small wild corner of the yard will provide habitat.
Moisture – moist soil is needed for their eggs and larvae; trees and leaf litter will provide moist areas; if you can provide a natural pond, the larvae will eat the insects, grubs and snails from the pond. (And lest we romanticize these insects too much, some species eat each other as well!)
Lower your lights – outside lighting can significantly disrupt the males’ flashes, and prevent females from responding, keeping them from finding a mate. Turn lights down or off when you aren’t outside, or use shielded motion-sensing lights, especially during mating season.
Plant native trees and shrubs, for the shade and leaf litter. They especially like pine trees.
Don’t rake and dispose of leaves – you are throwing out firefly larvae. Leave the leaves under trees, or bag the leaves and use for garden compost in the spring.

While some species have eggs and larvae that glow, you likely are most familiar with the flashes used by the adults. Males fly around flashing, while the females wait in trees, shrubs or grass; when she sees a male she likes, she will flash at him. It’s not well known what, if anything, the adults eat. They may consume pollen or nectar, and a few species are known to use their flashes to lure other species to become their dinner rather than their mate.

Some species have synchronous flashes – they flash and go dark in unison. Firefly.org has links to several places to view this beautiful phenomena – generally in May and June. When’s the best time to view fireflies in Ohio? It really depends on the weather. They are most active in warm, humid weather; the warmer the night, the brighter the display. An early warm spring can bring them out as early as April, but in general they start in early June and peak about the 4^th of July.

The light of the firefly is very efficient – 100% of the energy used to create the light goes into light. Since no heat is produced, it’s called “cold light”. The substances used to produce the glow (luciferase and luciferin) were at one time used for medical research, significantly lowering their insects’ numbers, but now they are produced synthetically.

What preys on fireflies? Not much – when attacked, fireflies shed drops of blood that are bitter, and poisonous to some animals; it’s called “reflex bleeding”. Most animals learn not to eat fireflies!

Mosquito control
The same conditions that support fireflies also support mosquitos. However, it is possible to be good firefly host without being overwhelmed by mosquitos.

Eliminate or clean any standing water in your yard – empty out any containers that collect water, add screens to your gutters so leaves don’t hold water in the gutters; add mosquito dunks to your rain barrels; replace the water in bird baths every day or so.
A fan will keep mosquitos away when you are sitting out – mosquitos are “weak flyers” and can’t compete with the moving air
Wear repellent; apply it after sunscreen for best results. While DEET based repellents work well, there are many organic products available, and you can even make your own with some essential oils
Doug Tallamy’s procedure for stopping the mosquito life cycle is easy and safe:
- Fill a bucket with water.
- Add straw or hay and let it ferment for a few days in a sunny spot. The resulting brew will be irresistible to female mosquitos.
- After a few days the mosquitos have laid their eggs, drop in a mosquito dunk tablet. Mosquito dunk tablets can be purchased at most hardware stores, and contain Bacillus-thuringiensis (Bt), a natural larvicide. The eggs will hatch and the larvae will die. This way you control the mosquitos and only the mosquitos, without the use of harmful insecticides. The pyrethroid-based insecticides used by mosquito foggers indiscriminately kill all insects, not just mosquitos. Ironically, targeting adult mosquitos is the worst and by far the most expensive approach to mosquito control, because mosquitos are best controlled in the larval stage. Fogging kills about 10% of the adult mosquitos.¹

Citizen science
Firefly lovers are encouraged to help scientists by recording and submitting observations to iNaturalist. Firefly.org has some guidelines here for recording and submitting your observations. While basic observations are helpful, they are interested in seeing both dorsal and ventral photos, flash pattern and color, date and time of night, location and type of habitat. You might be the one to discover a species thought to be lost in Ohio! BugGuide.net and the Boston Museum of Science’s MassAudubon project also welcome citizen observations.

https://www.firefly.org/

^1-Source for Mosquito trapping procedure

Thanks to Firefly Conservation & Research at Firefly.org for adult firefly photo. All others are stock images.