Long before humans figured out that sporting glowy lights could make you look really cool at dance parties, animals large and small had already figured out that light could be an advantage. Organisms that make their own light through bioluminescence use their flashy accessories to lure prey, attract mates, warn off predators, and perform a host of other functions.
Most bioluminescent organisms reside in the ocean, but landlubbers find ways to make good use of light too. Just recently, scientists discovered that bioluminescent mushrooms glow green in order to attract insects that help them disperse their spores, and while we’ve known of fireflies’ flashing abilities for a long time, late last year scientists learned how they actually add oxygen to their light-producing cells.
Science has taken advantage of natural glowing for its own ends—the Aequoria victoria jellyfish shown above was the source for the isolation of green fluorescent protein (GFP), which is used throughout biological experiments to measure gene expression. GFP, which earned its discoverers the 2008 Nobel Prize in Chemistry, lights up green when exposed to ultraviolet or blue light—the latter being produced by the jellyfish using the protein aequorin. Researchers have even isolated bioluminescent proteins from bacteria to create glow-in-the-dark plants. But equally beautiful specimens can be found out in nature. Here are some glowing examples.
While fireflies tend to glow on the green-yellow-red side of the spectrum, sea creatures tend to favor blue and green light since those shorter wavelengths are easier to see underwater. Here, three sea squirts give off a lovely fluorescent blue glow. Those two openings you see are conduits for water—one orifice sucks it in, the other expels it.
An exception to the rule, the stoplight loosejaw is the rare sea creature that deviates from a preference for blue-green light, producing a red bioluminescent glow from small organs called photophores underneath its eyes (it has another set of photophores that produces blue-green light). Because most other sea creatures can’t see red light, the loosejaw can search for meals without the illumination alerting their prey.
The marine worm Tomopteris is another uniquely accented bioluminescent creature. If something annoys this worm, it emits yellow sparks from the little paddle-like structures coming off of its body.
The species of mushroom known as Panellus stipticus is just one of many kinds of bioluminescent fungi. Glowing mushrooms are thought to use some form of luciferase to produce their light, which is sometimes called “foxfire.”
Bioluminescent microorganisms can create wonderful glowing tides. Often, these tiny plankton will squirt bioluminescent material out of their bodies to distract predators, which will chase after the glowing stuff instead of the plankton themselves.
The vampire squid may not be able to suck blood or turn into a bat, but it does have the eerie ability to eject a cloud of blue-glowing mucus to confuse predators. This camouflage process is called counter illumination.
Several groups of insects can create light in their larval stages and are usually referred to as “glowworms” (which are not actually worms but insects).
The lure that female anglerfish sport on their heads is lit not by the fish itself, but by the symbiotic bioluminescent bacteria that live inside it. Read more on anglerfish.
The feather-like sea pen lights up green when disturbed, probably to startle predators like the sea star.
The greenish light given off by the Antarctic krill may be a way for these tiny, shrimp-like creatures to mask their shadow from predators lurking beneath them; or bioluminescence might possibly help krill communicate with each other.
The bobtail squid plays host to the bioluminescent Vibrio fischeri. The symbiosis is so finely tuned that the bacteria will adjust how much light they emit depending on the amount of sunlight or moonlight streaming down from above.
Image: istock / GaryKavanagh, Wiki CC / art farmer, istock / singularone, Wiki CC / Rafael Bañón, Wiki CC / Ylem, istock / watcherFF, Carl Chun, David Evans, New Zealand-American Submarine Ring of Fire 2005 Exploration, Wiki CC / Nick Hobgood, Wiki CC / Uwe Kils
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