David Fleetham / Blue-spotted Sea Urchin (Astropyga radiata) expelling waste from the sac in the center of it's body. Maui, Hawaii.

Constantinos Petrinos / Yellow stripe clingfish (Diademichthys lineatus) living in association with the Fire Urchin (Astropyga radiata) Lembeh Strait, North Sulawesi, Indonesia.

Floris van Breugel / Various fluorescent minerals : 1Willemite, New Jersey, 2: Willemite and Calcite, New Jersey, 3: Fluorite, Ohio, 4: Willemite and Calcite, New Jersey. 5: Fluorite, California. 6: Scheelite, California....

Juergen Freund / Fluorescent corals (Trachyphyllia geoffroyi) Great Barrier Reef, Australia

Juergen Freund / Fluorescent corals (Favia sp) Great Barrier Reef, Australia

Georgette Douwma / False fire urchin (Astropyga radiata) grouped on sandy bottom. Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Radiant sea urchin {Astropyga radiata} with Cardinal fish Sulawesi Indonesia

Heather Angel / Voodoo lily (Amorphophallus bulbifer), female flowers fluroescing in UV light, male flowers above. Native to Yunnan, China.

Heather Angel / Love-in-a-mist (Nigella damascena) stamens fluroescing in UV light. Ring of nectaries are dark red with blue UV reflective hairs.

Heather Angel / Flannel bush (Fremontodendron 'California Glory') exposed and overflowing nectaries fluorescuing in UV light. Native to southwest USA.

Heather Angel / Christmas rose (Helleborus niger) flower, pollen on dehisced anthers and on petals fluorescing in UV light. Nectar ring appearing red. Focus stacked.

Heather Angel / Goat willow (Salix caprea) female catkin in UV light, fine hairs and nectar fluroescing. Surrey, England, UK. Focus stacked.

Heather Angel / Geraldton wax flower (Chamelaucium uncinatum), nectar fluorescing in UV light. Western Australia. Controlled conditions, focus stacked. Series 1/2.

Heather Angel / Seville orange (Citrus aurantium) flower fluorescing in UV light, colour attractive to pollinators. Cultivated in glasshouse, Surrey, England, UK. Focus stacked. Sequence 2/2.

Heather Angel / Winter aconite (Eranthis hymenalis) in UV light, pollen on outer stamens that have dehisced fluorescing. Focus stacked.

Heather Angel / Common rue (Ruta graveolens) flower in UV light, pollen and nectar at base of petals fluorescing. Insect pollinators are able to see position of rewards on offer. Surrey, England, UK. Native to Balkan...

Heather Angel / Tulip tree (Liriodendron tulipifera) flower, pollen and nectar fluorescing in UV light. Surrey, England, UK. Native to USA. Focus stacked. Sequence 2/2.

Heather Angel / Porcelain orchid (Chloraea magellanica) with osmophores on lip fluorescing in UV light. Chile. Controlled conditions, focus stacked. Sequence 2/2.

Alex Mustard / Mushroom coral (Fungia sp.) fluoresces a bright orange at depth. At this depth underwater there is no orange light left, pigments within the coral absorb blue light and emit it as orange light (the re...

Joao Burini / Fluorescent mushrooms glowing in ultraviolet light. South-east Atlantic forest, Sao Miguel Arcanjo, Sao Paulo, Brazil.

David Fleetham / Detail of Blue-spotted Sea Urchin (Astropyga radiata). A rare visitor to Hawaii.

David Fleetham / Adam's urchin / Zebra crab (Zebrida adamsii) carrying eggs under its body on a venomous Radiant sea urchin (Astropyga radiata). Rinca island, Komodo National Park, Indonesia.

Constantinos Petrinos / Aggregation of Blue-spotted urchins (Astropyga radiata) Lembeh Strait, North Sulawesi, Indonesia.

Constantinos Petrinos / Aggregation of Blue-spotted urchins (Astropyga radiata) Lembeh Strait, North Sulawesi, Indonesia.

Constantinos Petrinos / Fire urchin (Astropyga radiata) close up, Lembeh Strait, North Sulawesi, Indonesia.

Constantinos Petrinos / Yellow stripe clingfish (Diademichthys lineatus) living in association with the Fire Urchin (Astropyga radiata) Lembeh Strait, North Sulawesi, Indonesia.

Alex Mustard / Banggai cardinalfish (Pterapogon kaudemi) swimming over a long-spined sea urchin (Astropyga radiata) Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Radiant sea urchins (Astropyga radiata) home toZebra urchin crab (Zebrida adamsii) and banggai cardinalfish (Pterapogon kaudemi) with schooling silversides behind, in shallow water. Bitung, North Sul...

Solvin Zankl / Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Bearded fireworm (Hermodice carunculata) photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Bearded fireworm (Hermodice carunculata) photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Bearded fireworm (Hermodice carunculata) photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Solvin Zankl / Fluorescent coral photographed with ultraviolet / UV light, Bonaire, Leeward Antilles, Caribbean region, Netherlands Antilles

Adrian Davies / Scorpion (Heterometrus sp) fluorescing in ultraviolet light at night on forest floor, Danum Valley, Sabah, Borneo

Georgette Douwma / Flamboyant cuttlefish (Metasepia pfefferi) walking across the sand past a Long spined sea urching (Astropyga radiata) Lembeh Strait, Sulawesi, Indonesia.

Constantinos Petrinos / Urchin carrier crab (Dorippe frascone) carrying a Fire Urchin (Astropyga radiata) for camouflage and protection. Lembeh Strait, North Sulawesi, Indonesia.

Jack Dykinga / Glowing gases rising from Halemaumau Crater, Kilauea Caldera, in evening with Milky Way in the sky above. Hawaii Volcanoes National Park, Hawaii, August 2010.

Floris van Breugel / Green fluorescent proteins, naturally produced by sea anemones, emit green visible light under ultraviolet light seen here in their natural habitat under the stars on the coast of Olympic National Par...

MYN / Carsten Krieger / Sea Lettuce (Ulva lactuca) from tide pool, County Clare, Republic of Ireland, December. Meetyourneighbours.net project

Norbert Wu / Sea Urchin Cardinalfish (Siphamia versicolor) juveniles hiding in venomous spines of Radiant Sea Urchin (Astropyga radiata), Bali, Indonesia

Birgitte Wilms / Radiant Sea Urchin (Astropyga radiata) on Decorator Crab (Camposcia retusa), Indonesia

Juergen Freund / Radient sea urchins (Astropyga radiata) on the sandy bottom. Lembeh Strait, North Sulawesi, Indonesia

Sue Daly / False fire / Radiant sea urchin (Astropyga radiata) Lembeh Straits, Sulawesi, Indonesia

Sue Daly / Close up of spines of False fire / Radiant sea urchin (Astropyga radiata) Lembeh Straits, Sulawesi, Indonesia

GEORGETTE DOUWMA / False fire urchin (Astropyga radiata) grouped on sandy bottom. Lembeh Strait, North Sulawesi, Indonesia

GEORGETTE DOUWMA / Radiant sea urchin {Astropyga radiata} carried on the back of a Dorippid crab (Dorippe frascone). Lembeh Strait, North Sulawesi, Indonesia.

GEORGETTE DOUWMA / Juvenile Red emperor fish {Lutjanus sebae} seeking shelter amongst Radiant sea / False fire urchins {Astropyga radiata}, Lembeh Strait, North Sulawesi, Indonesia

GEORGETTE DOUWMA / Juvenile Red emperor fish {Lutjanus sebae} seeking shelter amongst Radiant sea / False fire urchins {Astropyga radiata}, Lembeh Strait, North Sulawesi, Indonesia

Chris Newbert / Radiant Sea Urchin (Astropyga radiata) detail, 80 feet deep, Papua New Guinea

GEORGETTE DOUWMA / Radiant sea urchin / False fire urchin (Astropyga radiata) Lembeh Strait, North Sulawesi, Indonesia

GEORGETTE DOUWMA / Radiant sea urchin / False fire urchin (Astropyga radiata) Lembeh Strait, North Sulawesi, Indonesia

Michio Hoshino / Bearberry (Arctostaphylos uva ursi), Blueberry (Vaccinium sp), and Horsetail (Equisetum sp) in trundra, Alaska

Tim Fitzharris / Bearberry (Arctostaphylos uva ursi) on forest floor in autumn, Yukon Territory, Canada

Michael Quinton / Tundra Vole (Microtus oeconomus) hiding in autumn colored Bearberry (Arctostaphylos uva ursi) leaves

Michio Hoshino / Bearberry (Arctostaphylos uva ursi) close up, Alaska

Michio Hoshino / Bearberry (Arctostaphylos uva ursi) and Cup Lichen (Cladonia sp) in tundra, Alaska

Constantinos Petrinos / Sea urchin {Astropyga radiata} on crab, Sulawesi, Indonesia

GEORGETTE DOUWMA / Radiant sea urchins (Astropyga radiata). Sulawesi, Indonesia

Constantinos Petrinos / Radiant sea urchins grouped on sea floor {Astropyga radiata} Sulawesi Indonesia - small fish find safety amongst their spines. Indo Pacific

Constantinos Petrinos / Radiant sea urchins {Astropyga radiata} stick close together in defence on sea floor Sulawesi Indonesia, providing shelter / mini habitat for fish and crabs

Gary Bell/ Oceanwide / Cardinalfish (Apogonidae) juveniles sheltering amongst Radiant Sea Urchin (Astropyga radiata) spine, Bali, Indonesia

David Fleetham / Blue-spotted sea urchin (Astropyga radiata), Hawaii.

David Fleetham / Radiant / Blue spotted sea urchin (Astropyga radiata), on a coral head, with two (male and female) resident shrimp (Stegopontonia commensalis), with diver behind, Hawaii.

Birgitte Wilms / Radiant Sea Urchin (Astropyga radiata) on Decorator Crab (Camposcia retusa), Indonesia

GEORGETTE DOUWMA / Radiant sea urchin {Astropyga radiata} with small urchin crab {Becrida adamsii} Indonesia

Adrian Davies / Mould on Satsuma under visible light (top) and fluorescing under UV light (bottom).

Joel Sartore / Photo Ark / Thick-pincer scorpion (Vachoniolus globimanus) under UV light showing fluorescence, portrait, Fujairah Wildlife, UAE. Captive.

Joel Sartore / Photo Ark / Shield-tailed scorpion (Apistobuthus pterygocercus) under UV light showing fluorescence, portrait, Fujairah Wildlife, UAE. Captive.

Joel Sartore / Photo Ark / Star sea urchin (Astropyga radiata) portrait, National Aquarium, Abu Dhabi. Captive, occurs in Indo-Pacific.

Alex Mustard / Coral fluorescence (Acropora sp.) at night, with lights from Misool Resort in background, Misool, Raja Ampat, West Papua, Ceram Sea, Pacific Ocean.

Alex Mustard / Coral fluorescence (Isopora sp.) at dusk, with lights of Misool Resort in background, Misool, Raja Ampat, West Papua, Ceram Sea, Pacific Ocean.

Alex Mustard / Coral fluorescence (Acropora sp.) at night, photographed under blue light, Raja Ampat, West Papua, Ceram Sea, Pacific Ocean.

Alex Mustard / Coral fluorescence (Acropora sp.) at night, photographed under blue light, Raja Ampat, West Papua, Ceram Sea, Pacific Ocean.

Alex Mustard / Coral fluorescence (Acropora sp.) at night, photographed under blue light, Raja Ampat, West Papua, Ceram Sea, Pacific Ocean.

Solvin Zankl / Scorpion (Pandinus sp.) fluorescing under ultraviolet light.

Adrian Davies / Sulphur tuft fungi (Hypholoma fasciculare) in visible light (top) and fluorescing in UV light (bottom), Surrey, UK.

Adrian Davies / Bowl of fruit in UV light showing mould on Satsuma (Citrus sp.). See 1729463.

Adrian Davies / Minerals in visible light on left and fluorescing in UV light on right. Top: Autunite; Centre: Wernerite; Bottom: Willemite.

Tony Wu / Female Pfeiffer's top shell (Tegula pfeifferi) broadcast spawning, from elevated spot in raised vertical position, by ejecting clusters of green eggs. East China Sea, Kagoshima Prefecture, Japan...

Tony Wu / Veliger, planktonic larva about 5mm, of Oregon hairy triton (Fusitriton oregonensis) in its shell suggesting that it is reaching maturity. Pacific Ocean, Hokkaido, Japan.

Tony Wu / Veliger, planktonic larva about 5mm, of Oregon hairy triton (Fusitriton oregonensis) in its shell, suggesting that it is reaching maturity. Pacific Ocean, Hokkaido, Japan.

Tony Wu / Sequence of veliger, planktonic larva about 5mm, of Oregon hairy triton (Fusitriton oregonensis) emerging from its shell. Pacific Ocean, Hokkaido, Japan. Composite image.

Tony Wu / Female Bivalve mollusc (Bivalvia) of indeterminate species, embedded in coral reef, broadcast spawning orange strands of tiny eggs, with Nagasaki damsel (Pomacentrus nagasakiensis) rushing to feed on...

Tony Wu / Female Bivalve mollusc (Bivalvia) of indeterminate species, embedded in coral reef, broadcast spawning orange strands of tiny eggs, with Nagasaki damsel (Pomacentrus nagasakiensis) rushing to feed on...

Tony Wu / Close-up view of polyps of coral (Alveopora japonica). Sea of Japan, Yamaguchi Prefecture, Japan.

Tony Wu / Close-up view of polyps of coral (Alveopora japonica) with two planulas, larval corals, emerging from coral mouth. Sea of Japan, Yamaguchi Prefecture, Japan.