The firefly, an insect that emits light


The firefly is distinguished by its ability to emit a bright light. Portrait of an insect that uses its tealight abdomen to find a mate and repel predators.

What do fireflies look like?

Fireflies (Lampyridae) form a family of beetles which has the particularity of being able to emit light. There are more than 2,000 species, including the famous glowworm. Their head is hidden under a large flat pronotum forming part of the thorax. Only the last two or three segments to the‘end of the abdomen can light up and sport a light tint when they are “off”. The elytra of the firefly – which protect them from external aggressions – are usually brown or black in color and are frequently marked with yellow or orange. A second pair ofwings, folded under the elytra, they are used to fly. Namely, females of some species are wingless. Fireflies having no lungs, they use special tubes (tracheoles) to carry oxygen around their body. These insects are between 5 and 25 mm in length and the female is usually a little more big than the male.

How do fireflies shine?

The light scattered by the firefly comes from a chemical reaction produced inside his abdomen. The two ways of emitting light are incandescence (the production of heat creates the luminous phenomenon) and luminescence (production of a photon, particle cold). This is the second technique used by this beetle. Its abdomen has a tealight organ that contains two types of molecules: a protein (luciferin) and an enzyme (luciferase). At will, the firefly causes the contact of these two molecules which, in the presence oxygen, will react by lighting up. The glow, usually yellow or green, can emit continuously or by alternation. In addition, the insect can control the strength of the light and the frequency of flashes at will.

Why do fireflies glow?

The bioluminescence of fireflies is a mode of communication mainly used to find a partner in times of reproduction. Each species has its own emission code (light intensity, frequency of flashes), the males can thus recognize the females of their family. At the same time, the brightness also has a function of defense. Indeed, fireflies make steroids called lucibufagins which tastes extremely unpleasant. The action of shining allows it to cause and signal the appearance of this substance to possible predators who prefer to turn back

Where do fireflies live?

Fireflies are found in North America, Asia and Europe where the most frequently observed species is the glowworm (Lampyris noctiluca). The insect is seen at night in deciduous forests, clearings or meadows, often near areas aquatic like ponds and marshes. During the day, the adults stand on vegetation, in crevices in bark or in wood. decomposition (old stumps). As for the larvae, they live at ground level, under the bark and in damp places.

What do fireflies eat?

Fireflies fall under the category of insects useful because their larvae and some adults feed on parasites of the garden. The diet of the beetle includes spiders, ants, worms, snails, slugs and various small invertebrates. The beetle injects digestive acids in its prey in order to paralyze it then sucks the contents of its victim. While some species of fireflies are herbivores – consuming nectar and pollen – other adults do not eat at all, a phenomenon which is explained by their very short lifespan.

How do fireflies reproduce?

A few days after mating, the female lays her eggs in a humid place and the couple dies shortly after. The eggs, which hatch about a month later, give larvae having a long, flat body. These settle in a shelter that they have dug a few centimeters below the surface of the ground. The main activity fireflies – which spend most of their lives in the larval stage – consists of feed. A series of molts, the number of which varies according to the species, will then transform the larva into nymph. After ten days in the spring, the insect splits the cuticle covering its body and becomes a adult for whom life will begin with the search for a partner. The majority of firefly species have a life cycle lasting two years.