Bat signal: Fireflies' glow tells bats they taste awful

August 22, 2018 by Seth Borenstein

Fireflies flash not just for sex, but survival, a new study suggests.

Scientists wanted to find out if there's more to the lightning bug's signature blinking glow than finding a mate. Some experts had speculated it was a glaring signal to predators, like bats, that fireflies taste bad.

To test out whether the glow acted like a flashing bad Yelp review, researchers at Boise State University put bats and fireflies in front of high-speed cameras. They published their results in Wednesday's journal Science Advances .

The painstaking experiment required researchers to introduce western bats, which had never seen lightning bugs before, to the insects. Later, they hand-painted firefly bellies black, essentially turning off their night lights, avoiding the holes the critters breathe through.

When the bats first saw the unfamiliar lit-up fireflies, they swooped in and munched on them, only to get a bad taste in their mouths.

"They shake their heads, salivate and spit and generally despise their caretakers for giving such a rude meal," said study author Jesse Barber, a Boise State biology professor.

After a few tries, the bats then avoided the glowing fireflies. (Despite the popular misconception, bats aren't blind, a study author noted.)

Once the fireflies essentially taught bats that they taste bad, Barber and colleagues introduced the darkened fireflies. About 40 percent of the painted ones were munched, while none of the normal fireflies were eaten.

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Firefly sex success: the secret is in the gift-giving

Male fireflies, known for attracting mates with a flash of light, also seduce with a gift, say scientists.

This gifts comes in the form of a spermatophore: a package containing sperm and nourishment for the female.

Researchers from Tufts University in Boston, US, found that females preferred males that had the largest, most nourishing gift.

The team presented their findings at the First Joint Congress on Evolutionary Biology in Ottawa, Canada.

With supervision from his colleague Sara Lewis, who has been studying fireflies for 20 years, Dr Adam South used LED lights to mimic the flashes of amorous male fireflies.

They showed one group of females artificial male flashes in patterns and durations that had been proven attractive in previous studies. Another group of females saw "unattractive" flashes.

In the wild, females are very picky about what males they reveal themselves to during this part of the courtship routine. Females will only "flash back" to males they are attracted to.

But in this experimental set-up, after several minutes of the courtship flashing, males and females were paired together in miniature chambers. The Tufts biologists filmed the encounters under infrared illumination to see what was happening when the lights went out.

Continued:  http://www.bbc.co.uk/nature/18736948

How 'bioluminescent' trees that glow like fireflies could one day replace our streetlights

By Niall Firth


Scientists are developing ways of making trees glow so they can be used as natural streetlights without the need for electricity.

A team of researchers are experimenting with genes to allow the trait that causes fireflies to glow -bioluminescence - to be implanted into a variety of different organisms.

As well as replacing traditional streetlights, bioluminescent plants would be useful for people who are not hooked up to the electricity grid.

And if more lights were ever required, they could simply be grown.

The scientists at Cambridge University used genes from fireflies and a special form of glowing sea bacteria to create ‘BioBricks’ – genetic building blocks that can be inserted into a genome.


After inserting the modified genes into a sample of e-coli bacteria they were able to produce a range of colours – and created a living light that was bright enough to read by.

The scientists created the glowing effect by creating a substance known as oxyluciferin which is naturally in a high-energy state at first. However it quickly settles into a more stable, lower-energy state, and when it does so it emits a single photon of light.

Geneticist Theo Sanderson, one of the members of the team, told New Scientist: ‘We didn't end up making bioluminescent trees, which was the inspiration for the project.

‘But we decided to make a set of parts that would allow future researchers to use bioluminescence more effectively.’

The research was presented at the annual International Genetically Engineered Machines competition (iGEM), held at the Massachusetts Institute of Technology.

The technology could even be used to make glowing signs that do not need to be wired up

The team say that there is huge commercial potential in replacing the street with natural bioluminescent systems.

The idea is also extremely environmentally friendly as no electricity would be required and the process which produces the photons of light is extremely energy-efficient.

The scientists have also considered the possibility that the fuel to fire the chemical reaction in the trees could come from human waste or food waste.

And if the plant species used was a form of algae then energy could be harnessed from sunlight.

The team say on their website: ‘We might imagine a system where a bioreactor in the roof of a house - supplied with leftover foodstuffs - could pipe glowing algae through the rooms of the house during the night and across the roof during the day.’

In separate research, Taiwanese scientists have found that inserting gold nanoparticles into the leaves of trees helped the chlorophyll to glow red.

Under ultraviolet light the nanoparticles glowed with blue light, causing the surrounding chlorophyll to glow red.