Special ability helps fireflies 'show light' at night

Every summer, fireflies 'pop' the night sky in bizarre bioluminescent displays, in all colors - green, yellow, orange and even blue.

Science knows of more than 2,000 species of fireflies, each with its own unique flashing pattern and differently shaped light-emitting organs.

But have you ever wondered how these glowing insects do it? Scientists certainly have – and they've discovered two key genes that give fireflies their special 'powers' .

(Source: National Geographic).

'There are 'two gems' in firefly research ,' said Xinhua Fu, a biologist at Huazhong Agricultural University in China.

1. The first is how firefly larvae rapidly develop their light-emitting organs into a completely different physical structure as adults.
2. The second is how adult fireflies can manipulate these organs – often called 'lanterns' – so precisely, for example flashing in Morse code-like 'patterns' when their attractive mates are nearby.

In a study published in the journal Nature Communications, Fu and co-author Xinlei Zhu sequenced the genome of a water firefly, Aquatica leii , found in rice fields in China.

They focused on two key genes responsible for the formation, activation and positioning of this firefly light organ : Alabd-B and AlUnc-4.

This was a surprise, as these genes were already known to support firefly development, but had never been linked to bioluminescence.

Fu said the discovery could eventually help scientists understand how these beetles evolved the ability to glow like fireworks.

Fu said the work is also important because firefly populations are in 'free fall' globally. Eighteen species are currently facing extinction in the United States, and many others around the world are at similar risk, due to light pollution, pesticide use, habitat loss and other factors.

The secret of the 'flickering' light

As it turns out, the firefly species involved in this study is one that Fu loves: "He discovered the species and has been studying it since 2000, even keeping a colony of them in the lab — which produces up to 600,000 fireflies a year."

This population allowed him to further his research into the precise 24-hour period immediately after pupation, when their adult light organs develop.

(Source: The New York Times).

In an experiment this year, Fu and Zhu began editing the genomes of these insects to see what effects were produced by 'turning off' or removing certain genes.

They found that during pupation , fireflies activate the genes Alabd-B and AlUnc-4, causing the adult 'lanterns' to develop in the correct position in their abdomens.

Jing-Ke Weng, a biochemist and director of the Plant-Human Interface Institute at Northeastern University in Boston, said the study was "impressive" because it used cutting-edge tools and genomic analysis.

Weng said the research lays the groundwork for understanding how the common ancestor of fireflies combined these two genes to produce light.

However, there are still many challenges ahead in expanding evolutionary research – partly due to their complex 'courtship' process . Raising fireflies is much more difficult than raising mice, fruit flies or other common research animals.

Furthermore, this study was limited to males of one species, A. leii, meaning the pathway remains unexplored in the other half of the population—the females. Fu plans to remedy this in a follow-up study.