Firefly (Lampyris noctiluca) of the genus Lampyris; is a invertebrate animal which is known to emit a bright green / yellow light at the end of its tail.

Firefly seen up close


It belongs to the lamprey family (Lampyridae) where there are also other insects such as: light bugs, curucusíes, isondúes, cucuyos and light worms. They are characterized by the ability to emit light (bioluminescence).


The firefly is a hard-shelled beetle that closes over the wings when not in use. It measures between 5 - 25 mm in length.

There is a notable sexual dimorphism between the sexes. Males are winged, with brown elytra, a lighter pronotum, and a large brown spot in the center. Females are larvae, wingless and often twice the size of males.

Light production

The production of light is vital for the development of the species. The insect regulates production by controlling the supply of oxygen that goes to the emitting membranes that contain luciferin. When oxygen comes into contact with lucferin, a chemical reaction occurs that produces light. This is catalyzed by luciferase, whose chemical structure is determined by individual genetics, which produces differences in light between individuals. All the energy produced is light, only 2% is heat.

They emit yellowish-green light from the translucent underside of their last three abdominal segments to attract smaller males, who have the ability to fly. To achieve this, they emit light for a couple of hours to retreat to their hiding place and continue the next night. They will continue to do so until they find their match, but they will not be able to extend much more than 10 consecutive nights.

The light can be seen by males up to 45 meters away. The light is emitted constantly, although the female will move the abdomen from one side to the other which produces the effect of on and off.

The larvae can glow as well and are able to turn off their light faster than females, especially when stressed.


Firefly It is a nocturnal animal, therefore, it is active at night, which is when you can see its bright behinds. The busiest period occurs between June and July.

Light is used to attract mates during mating season, although they can shine at any time of year. Males use light as an indicator of female fertility, so they will be more likely to approach brighter females, as they will be larger and will lay a greater number of eggs. They can also be attracted to artificial lights.

Field full of fireflies
Field full of fireflies


The firefly is found in slow-growing grasslands, swamps, or forests. They prefer humid environments and temperate climates, so it is possible to find them near rivers or other areas where there is a great abundance of water.


The firefly is distributed from Portugal to Great Britain in its western part, through Europe and Asia to eastern China. It also survives far north, skimming the Arctic Circle.

It cannot be found in North America, South America, South Asia, Africa, Australia, and Antarctica.


The firefly is an omnivorous animal, although the diet varies by species. Many species do not eat, while others feed exclusively on pollen and nectar. In other species, the females feed on other species of fireflies.


The firefly various predators due to its size and the light it emits. Their predators are: spiders, large insects, birds, reptiles and centipede.


The female firefly, unlike most animals, is the one who initiates mating. For the search for a mate, the female will attract the males with her bright light.

Once they have mated, the female lays 50-100 eggs in fairly humid areas such as grass stalks or under moss. It will take about three days for all the eggs to be laid. After laying eggs it will die.

The eggs are tiny in size, 1mm in diameter. They are pale yellow in color and take 3-6 weeks to hatch. Although this period depends on the weather, the warmer it is, the faster the eggs will hatch.

The larvae and females have a similar appearance, but the larvae have bright spots in each of the 12 segments, while the female lacks it, and only has a black color.

Larval stage

Once they hatch, the larvae become predatory animals and for two or three years they feed on slugs and snails that they kill by injecting them with a brown, toxic and digestive liquid that is supplied by bites. This poison takes a while to take effect, during this time the larva must be careful not to be caught by the prey, by some defensive reaction.

The prey is gradually paralyzed and the digestive fluid turns it into a brown liquid that the larva can absorb. During this process the prey is still alive and cases have been seen where some partially eaten ones crawl after being eaten.

They shed their skin four to five times in their life. Winter is spent under logs, stones, holes in wood or hajarasca, hibernating as food becomes scarce. When spring comes they wake up and repeat the cycle for two or three years.

They become adults during the months of May to July, surviving from the reserves accumulated during their larval stage, and dying after reproducing.

State of conservation

The firefly is in danger of extinction, due to its population decreasing dramatically. The main reason is the decline in populations due to the expansion of human civilization.

It is highly vulnerable to changes in its environment, where we include habitat destruction, habitat fragmentation, pollution, distraction from artificial lights, insufficient grazing, and climate change.

Relationship with humans

Legend has it that the first humans used to use them to mark paths and provide light to the huts.

Popular culture

In the past, various cultures believed that fireflies had some kind of magical power, which is why they were constantly used in medicines.

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