Fluorescence Is Widespread in Fish, Study Finds

It was the green eel that did it. Scientists from the American Museum of Natural History had been exploring a reef off Little Cayman Island, investigating fluorescent coral and gathering photos for an exhibition.

In reviewing images taken during the team’s dives, the researchers spotted a glowing, apparently fluorescent, green eel.

So began four more expeditions to the Bahamas and the Solomon Islands with scuba divers and submersibles, leading to the discovery that biofluorescence is actually widespread in fish, present in at least 180 species and 16 orders.

The findings, reported in the journal PLoS One on Wednesday, have implications for the evolution and behavior of these fishes. They may also provide new chemicals for laboratory research, according to the authors, including John S. Sparks of the American Museum of Natural History and David Gruber of the museum and the City University of New York.

Bioluminescent organisms like fish and fireflies produce their own light. Biofluorescent fish and corals do something different, absorbing blue light, which is relatively high-energy, and transforming it into relatively lower green, orange and red light. Some organisms do both.

The proteins involved in fluorescence are prized by researchers, who adapt them to light up different biological processes. In 2008 the Nobel Prize was awarded to three scientists for the discovery in jellyfish, and adaptation for research, of what is usually called G.F.P., for green fluorescent protein.

The findings also have evolutionary significance, as the authors of the paper point out.

Most of the fish species they identified are camouflaged, so they are usually nearly invisible, at least to humans. But they need to find each other, including during mating. The researchers say they think that these species can probably see fluorescence easily.

Human divers can see it, but not very well unless they shine an intense blue light on the organisms, producing higher levels of fluorescence, as the divers did on the reef off Little Cayman.

The traveling exhibit they were working on at the time, “Creatures of Light: Nature’s Bioluminescence,” will open in May at the Canadian Museum of Nature in Ottawa. It ended its run in New York at the American Museum of Natural History in 2013.

Links:

Original article in PLOSone:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0083259;jsessionid=6039AD94E1E8460D142B38305665373B

NY Times article (with great video) http://www.nytimes.com/2014/01/09/science/fluorescence-is-widespread-in-fish-study-finds.html?_r=0

Nature News:

http://www.nature.com/news/fish-flaunt-neon-glow-1.14488

ScienceNow:

http://news.sciencemag.org/evolution/2014/01/fish-put-light-show

National Geographic News:

http://news.nationalgeographic.com/news/2014/01/140108-coral-reef-fish-biofluorescence-ocean-animal-science/

World Science Festival blog:

http://worldsciencefestival.com/blog/researchers_unveil_rich_world_of_fish_biofluorescence

National Geographic:

http://news.nationalgeographic.com/news/2014/01/140108-coral-reef-fish-biofluorescence-ocean-animal-science/

Research sheds light onto the debut of insect life on Earth

LAWRENCE — “Insects dominate our world,” according to University of Kansas researcher Michael Engel. Thus, anything scientists can learn about the evolution of insects leads to a better grasp of how biology in general has changed over time.

“More than half of all known species on the planet are insects, and they rule virtually all terrestrial and freshwater ecosystems,” said Engel, a professor of ecology and evolutionary biology. “Many insect lineages are ecologically ubiquitous — such as bees, ants, termites — and they impact our daily lives in a big way. They pollinate our crops; they are the sources of many of our medicines or other chemicals; and some are tied to the spread of disease.”

Understanding the factors that led to insect origins and fueled their successes, as well as what pushed particular groups to extinction, such as the influence of climate change, is vital to human health and security.
Engel has just co-authored a paper in the prestigious journal Nature that sheds new light on the evolution of the Eumetabola, a scientific term for the group of organisms that includes most insect species.
“Beetles, bees, ants, wasps, flies, butterflies, moths, fleas, lacewings, lice, thrips, aphids, true bugs and all of their close relatives are eumetabolous insects,” said Engel. “If you are talking about insects, then you are likely talking about a eumetabolan insect.”

The researcher, who also serves as a senior curator at KU’s Biodiversity Institute, said that in spite of the importance of this group of insects, their earliest origins have been difficult to pin down.
“There’s been a lack of identifiable fossils from the Carboniferous Period or earlier deposits,” Engel said. “Until now, the first definitive specimens assignable to the Holometabola, the big chunk of the already massive Eumetabola, were from the early Permian — but those aren’t the most primitive of their kind, except in a few cases, and pointed to much earlier diversification events. From the Carboniferous, the immediately preceding time period, we only had specimens of much more primitive insect lineages. “

The size of the fossils makes them difficult to detect, according to Engel.

“They’re tiny, so unless you are hunting for them, they would be easy to overlook,” he said. “Also, fossils from these deposits aren’t preserved with a strong contrast between them and the surrounding rock. Thus, it takes specialized lighting to get them to easily pop out.”

Nevertheless, Engel and his co-authors in Nature describe newly discovered specimens and fragments that can be confidently tied to holometabolan lineages. More significant, the specimens are not of the typical orders but are far more primitive.

“For example, there’s a species related to the lineage that eventually would give rise to the wasps in Triassic,” he said. “It wasn’t a wasp itself and instead would look more like some kind of generalized primitive group, but it already had a few of the evolutionary novelties that would later be part of the order of wasps, ants and bees.”
Among the other five species Engel and his colleagues describe in Nature, one is an early relative of true bugs and their relatives; one is an early relative of barklice, and then ultimately true lice; and one is an early relative of the lineage that would give rise to the beetles in the Permian.

KU is a leader in paleontology generally, and Engel’s lab is one of a few worldwide with expertise in the fossil record of insects — and, among those labs, an even smaller subset have sufficient expertise in the Paleozoic.

Engel said an understanding of ancient development and origins of insects is vital for an understanding of our modern world.

“Our own evolution — biotic and cultural — is inextricably woven into the lives of insects,” he said. “Insects have been on the planet for at least 410 million years and were first to fly, first to develop agriculture and first to form complex societies. We like to talk about the ‘Age of Dinosaurs’ or the ‘Age of Mammals,’ but all of these are greatly dwarfed by an overarching ‘Age of Insects.’ If humans vanished from the Earth it would have only a beneficial effect on the greater biota. If insects disappeared, then life itself would struggle to persist.”


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