Image of the Day: Light Show
Image of the Day: Light Show

Image of the Day: Light Show

Sea fireflies spew a mucus with a chemical glow to lure mates and avoid being eaten.

Carolyn Wilke
Feb 7, 2019

ABOVE: An ostracod leaves a swirling trail of light. In the top-left of this photo, the ostracod is trapped in a fish’s mouth and the bioluminescence moves through the fish’s gills and into the water.

Cypridinid ostracods, also known as sea fireflies, leave a trail of light in their wake as they swim. The bioluminescence of these tiny crustaceans attracts mates and helps protect them from predators. But unlike unrelated winged fireflies, these seafarers create light outside of their bodies by spewing a trail of mucus containing an enzyme and substrate that react with each other to produce the glow. A new report illuminates how ostracod species produce different lengths of flashes through various combinations of enzymes and different amounts of substrates, researchers reported January 16 in Proceedings of the Royal Society B.

N.M. Hensley et al., “Phenotypic evolution shaped by current enzyme function in the bioluminescent courtship signals of sea fireflies,” P Roy Soc B, doi:10.1098/rspb.2018.2621, 2019.