This can lead male fireflies into thinking they have found a colony of brightly glowing females. Artificial light in night environments is increasing, even in countryside areas. Their glow may be being used to signal that they wouldn't be a pleasant meal for predators.įireflies' lives revolve around light. In species of firefly where the larvae glow prominently, this is probably for defence. The females mimic the light patterns of other species, attracting males to kill and eat them. This is one of the main ways for fireflies to tell if they're receiving a message from the same species.įireflies in the genus Photuris, found in North America, are often called femme fatale lightning bugs. In non-glow-worm fireflies, males and females communicate by both flashing their lights in specific patterns and tempos to identify themselves. Instead they produce a sustained stream of light. A chemical reaction with the light-emitting enzyme luciferase produces their illuminations.īut glow-worms can't easily control the supply of oxygen, so they can't flash their lights on and off like some other firefly species. You can’t get them to do what you want … so it involves a bit of cajoling to get the protein happy in the lab.In glow-worms, a molecule called luciferin is combined with oxygen to create oxyluciferin. Because protein molecules, I think, are a lot like cats.
“The biggest challenge is making the protein happy. This process can be time-consuming and frustrating. Then we use protein crystallography to generate enough data to allow us to do the structure of all the atoms of the enzyme.
“Then we have to purify it, and grow crystals of it - which look like mineral crystals but are crystals of proteins. “We have to figure the best way to get a lot of the enzyme,” says her collaborator Kurt Krause. To try and produce more squid protein crystals to work with, Miriam has gone back to the tried and true technique she has been using with the glow worms - growing crystals in the lab. The proteins in the crystals are enzymes which catalyse, or speed up, the chemical reactions that produce light.
That’s because squid and fireflies are not closely related – and their bioluminescent abilities have evolved independently. “The crazy thing,” says Miriam, “is there are three proteins in the crystals … and it turns out they are in the same super-family of proteins as the bioluminescent proteins you find in fireflies, which is entirely unexpected.” As well as sequencing the RNA, which identifies the genes that encode each protein, she’s used mass spectrometry to sort the proteins by size. But what she has managed to do is identify the proteins, using two different techniques. Efforts to study the crystals with a giant microscope known as the Diamond Light Source synchotron have come up short, so Miriam is trying to devise new methods.
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