Firefly FAQs and General Ecology
First and foremost, let’s clarify something: fireflies = lightning bugs. These terms are interchangeable! We are all referring to the beautiful beetles that we see in the summer months.
Lifecycle of a firefly
The life cycle of a firefly consists of 4 stages: egg, larva, pupa, and adult. We are accustomed to seeing the adult form of a firefly, but this is a short-lived stage for them. Most of their lives are spent as larvae. As larvae, they live in the soil and leaf litter. Most firefly species overwinter as larvae, however, the winter firefly overwinters in their adult form!
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What makes a firefly a firefly? They glow at some point in their life cycle! This rule is how you can get diurnal fireflies that don’t flash as adults (winter fireflies, woodland lucys, and more), but because these species glowed during some stage of their lives, they are therefore a firefly!
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Fun fact: adult fireflies do not need to eat! They do eat during their larval stage, but as adults, most of their time is spent searching for mates and mating! It is still good practice to place an apple slice in a jar if you have caught a firefly; this is not because they need to eat the apple, rather because it contains moisture, and this is something they need!
Looking at fireflies: what am I seeing?
Most fireflies that you see displaying will be males. We can use male flash patterns to identify species, since these patterns are specific to each firefly species. Females do flash, but their flashing is more discreet and usually comes while they are perched on vegetation. The flashes of females are not as recognizable as male flash patterns, so we don't use female flashes for flash-based species ID.
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To figure out what species you may be seeing, you should consider where you are (in terms of habitat) and when you are making your observations. Certain species are associated with certain habitats. Some habitat examples are wetlands, forests, and fields. Considering when you are making your observations is helpful because different species of fireflies come out at different times of the night and different times of the season.
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You can also look at flash color! Yes, there are different colors of firefly flashes! These colors are yellow, green, and orange. As a very general rule of thumb, fireflies with yellow flashes are seen earlier in the evening and dusk, while fireflies that have green flashes are out later in the evening, after dark or late dusk. Fireflies that have orange flashes are oftentimes seen later in the night.
Biology basics
All fireflies are beetles (the scientific name for this order of insects is Coleoptera). This order makes up the largest group of all the insects! Most insects possess two pairs of wings, and in the case of beetles, one pair of wings acts more as a protective cover to their flight wings. These sheath wings are called “elytra.”
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Fireflies glow from their lanterns, which are organs located in their lower abdominal segments. Within these organs, luciferin (a chemical compound that fireflies possess) combines with oxygen to produce the light that we see!
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Looking at firefly lanterns can help us tell firefly sexes apart, at least in flashing species. Male fireflies will have lanterns on two lower abdominal segments, while females will have only one and it is smaller in size.
Femme Fatales
Some fireflies eat other fireflies! There is a genus of fireflies called “Photuris” and many of the species in this genera have predatory females. These females imitate flashes of other species of fireflies to lure in “mates.”
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You may be wondering why they do this. To answer this, we need to consider lucibufagins (yes, this is a real word!) This is a chemical that fireflies possess that is toxic to predators. Most fireflies have this chemical, however, Photuris do not make this chemical on their own. Because Photuris don’t have their own, they take it from the fireflies that do! This helps Photuris to protect their offspring from predation.
Fireflies in West Virginia
We can’t say for sure how many species of fireflies we have in West Virginia, because we are always finding more! There are at least 25. One common species we have in our state is the big dipper firefly (Photinus pyralis). These fireflies are commonly seen in yards and lawns.
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West Virginia also has synchronous fireflies! These fireflies are well-known for their coordinated display throughout the region; many people gather each year in the Great Smoky Mountains National Park to observe these famous displays.