#biofluorescence

MILLIPEDES GLOW IN THE DARK

A threatened cherry millipede coils into a defensive posture. This one looks entirely different in the beam of a regular flashlight (l) compared to the fluorescence displayed under a UV (ultraviolet) blacklight.

Read more: https://whitgibbons.com/millipedes

From the article:

Birds-of-paradise have some of the most famous mating displays in the world, but there's more to their colorful rhythmic gymnastics than initially meets the human eye. For the first time, scientists have discovered these spectacular avians absolutely glowing with gorgeousness in a dark room. Researchers at the American Museum of Natural History (AMNH) combed through the available archives and found that all 37 core bird-of-paradise species in Australia, New Guinea, and Indonesia are biofluorescent. Only a few fringe family members fail to glow under ambient UV or blue light.

Most male birds tested possess brightly fluorescent heads, napes, bills, and plumes that glimmer with green or greenish-yellow hues. Some even have fluorescent legs, feet, tails, and rings around their eyes. Many of these mysteriously colorful patches are starkly bordered by dark feathers with no fluorescence, and these parts of the body are often used in mating displays, when males flap, flutter, sway, bop, hang, and pose in an elaborate, attention-seeking dance that varies from species to species.

Note that this is different than bioluminescence. This is like those glow-in-the-dark stickers. They mention puffin beaks glowing under UV light.

(Check out the glasses they gave them in the second article!)

@todaysbird @alithographica

Research alert! In the past decade, Museum researchers have illuminated biofluorescence in more than 500 species across the tree of life, with a particular focus on fishes and other marine animals. Now, a new study reveals that birds-of-paradise—known for their dramatic plumage and elaborate courtship displays—can be added to that list. The study, published in The Royal Society Open Science, was led by Rene Martin, an assistant professor at the University of Nebraska-Lincoln who conducted this work when she was a Gerstner postdoctoral scholar at the Museum. The project began about a decade ago, when Curator John Sparks, an ichthyologist, conducted a rapid survey of the Museum’s vast Ornithology collection for biofluorescence in birds, which revealed bright green-yellow fluorescence in birds-of-paradise. Sparks’ initial work was continued recently by Martin and Emily Carr, a Ph.D. student in the Richard Gilder Graduate School. Using a specialized photography setup with ultraviolet and blue lights and emission filters, the team returned to the collection and found that biofluorescence is especially prominent in male birds-of-paradise. The researchers note that despite there being more than 10,000 described species, very few scientists have investigated the presence and use of biofluorescence broadly across birds. Read more about the findings in our latest blog post.

🎃 ~ Ascarium ~ 🎃 (itsalyssatime93)

“The Magic Rat and His Slick Machine”

“In Tasmania's southwest wilderness, many creatures stalk the night. Eastern quolls (Dasyurus viverrinus) are among them, harboring a very neat trick from us. Where their fur is normally fawn or black, under certain wavelengths of light, they exhibit a process referred to as biofluorescence – like nature's version of a white shirt glowing at a disco. All of the light and color in this image is the subject's natural glow in response to invisible UV light, exploding from its natural sandy colouration. This is the first documentation of the species glowing in the wild and forms part of ongoing research into the impacts of light pollution.”

Ben Alldridge

Pachydactylus rangei, commonly known as the Namib sand gecko, is a unique type of lizard that can be found only in the Namib Desert, which stretches across Namibia, Angola, and South Africa. This species is especially common along the arid coastal region known as the Skeleton Coast.

Above: Pachydactylus rangei

This is one of the only geckos in the world that is known to have fully-webbed feet; the unique morphology allows the gecko to run atop the sand and dig beneath the dunes, and it's able to escape from the blistering heat of the desert by burrowing down into the sand during the day and then emerging only at night, when the temperature finally drops.

Above: a close-up of the gecko's webbed foot

Namib sand geckos are covered in translucent scales, but their bodies often have a strangely colorful appearance, because their circulatory system, spinal column, internal organs, and optical membranes are partially visible through their skin. Those underlying structures produce various shades of pink, blue, purple, orange, and yellow.

Above: the colorful appearance of Pachydactylus rangei

These geckos also have very distinctive markings that fluoresce when exposed to UV light (including moonlight) which causes them to emit a bright, neon-green glow. The fluorescent dermal markings are unique to this species, and Pachydactylus rangei is the only terrestrial vertebrate that is known to have an iridophore-based form of biofluorescence.

Above: the patterns glowing under UV light

Researchers believe that the biofluorescent markings might allow the geckos to locate one another in the vast, desolate expanse of the desert, as this article explains:

The fluorescent areas of Pachydactylus rangei are concentrated around the eyes and along the lower flanks. This positioning is practically invisible to predators with a higher perspective (e.g. birds and jackals) but highly conspicuous from a gecko’s perspective. As Pachydactylus rangei is sociable but generally solitary, and occurs at low population densities, such a signal might serve to locate conspecifics over greater distances.

Above: a Namib sand gecko licking drops of condensation from its face and eyes

These lizards obtain moisture by licking the condensation that forms on their own bodies and on the bodies of other geckos, and they've been known to engage in social behavior with other members of the same species:

Encounters in Pachydactylus rangei might serve purposes beyond mating opportunities: as the Namib desert has extremely low precipitation, fog is a key water source for its flora and fauna. Fog condenses on the bodies of the geckos, and they lick it from their faces. In husbandry, we have observed individuals licking water from conspecifics, taking advantage of a much greater available surface area.

Additionally, after short periods of isolation, the geckos run to meet each other. The combination of vital hydration with socialisation might reinforce signals that enable such meetings, and the cost of visibility to predators with higher vantage points, might constrain the signals to regions best visible from eye-level and below.

Above: the photo at the top shows a Namib sand gecko emerging from its egg, while the photo on the bottom shows a freshly-hatched gecko screaming at the universe

Namib sand geckos can produce complex vocalizations, including squeaks, clicks, croaks, and barks, especially when they're startled, threatened, or attempting to attract a mate.

Above: close-up of Pachydactylus rangei

This species is also known as the web-footed gecko, Namib dune gecko, or palmatogecko.

Sources & More Info:

National Geographic: The Web-Footed Gecko

Animal Diversity Web: Pachydactylus rangei

Scientific Reports: Neon-Green Fluorescence in the Desert Gecko Pachydactylus rangei Caused by Iridophores

Tropical Zoology: Substrate Excavation in the Namibian Web-Footed Gecko and its Ecological Significance

Journal of Arid Environments: The Lizard with Kaleidoscope Eyes: Population Characteristics of the Namib Web-Footed Gecko, Pachydactylus rangei

Snakes and Other Reptiles and Amphibians: Web-Footed Gecko

Dr. Mark D. Scherz: A Neon-Green Glowing Gecko