Fireflies in Portugal

by Central Magazine

In the park in the dark

Article Cover Photo

I wondered if these amazing creatures were found in Portugal (I will get back to my discovery later) and stumbled on Parque Biológico de Gaia, a nature reserve in Avintes, around 17km south east of Porto. The park itself is the country’s first permanent Environmental Education centre, and consists of an agro-forestry area measuring 35 hectares, where hundreds of species of animals and plants live in the wild. 


The night of the Fireflies

Getting back to fireflies - one of the highlights of this park are the firefly walk nights that take place in June, something perhaps that you already knew about but haven’t seen yet. It’s well known locally so you need to book in advance, but they say it’s quite a show. For 20 years, Parque Biológico de Gaia has hosted a June firefly event that attracts more than 1,000 visitors over a 2-week span.

Credits: Unsplash; Author: evan-leith;

Fireflies themselves

Luciola lusitanica is the species of firefly that occurs in Portugal and also in the north of Italy, France, Corsica and Sardinia. However, their preferred habitat will be moist areas along the banks of rivers, streams and swampy forests, and therefore won’t be seen in the dryer areas of south Portugal.

Fireflies are found on almost every continent except Antarctica, and there are more than 2,000 species worldwide. Many species will share one habitat, and need a moist environment to survive, being found around wet or damp areas that retain moisture. They thrive in forests, fields and marshes near lakes, rivers and streams. Some species of firefly larvae live in trees while others are aquatic, even having gills.

Credits: Unsplash; Author: jerry-zhang;

Female fireflies lay eggs in the ground and the larvae will spend up to two years in this stage until they change or metamorphose into adult fireflies. They, like adults, emit a glow, but as a defence mechanism. The larvae are grub-like and vicious predators. They feed on worms, slugs, and snails by injecting them with a numbing fluid. Adult fireflies only live a few weeks and some feed on nectar or pollen, but most don’t eat at all. They just mate, lay eggs, and then die.

Credits: Unsplash; Author: krzysztof-maksimiuk;


The flashing ones are males looking for females, and flash a specific pattern when they fly in the hope that a female will reply. If she likes what she sees, she will respond with a flash of her own. They will have this ‘conversation’ until the male locates the female for their ‘get-together’. Each species of firefly has its own pattern, and allows the fireflies to find the right mates of the same species.

Credits: envato elements;

The Bad News - Fireflies are Disappearing

Yes, you guessed it, firefly populations all over the world are dwindling, and although no one knows for sure why, the main causes appear to be habitat loss, climate change, excessive light pollution and the use of pesticides – and it should be noted that biocides aften target snails, one of the fireflies’ main prey.  Light pollution is believed to interrupt firefly flash patterns, and artificial light from cars, street lights, etc may also make it difficult for fireflies to signal each other during mating, meaning fewer firefly larvae will be born every season.  

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