As the UN pressures Australia to better protect the Great Barrier Reef, here are some images of the spectacular wildlife harboured by this vast stretch of coral. From a manta ray cruising over a shipwreck to the effervescent ribbon eel, it’s a reminder of what is at stake.

Photograph: Reinhard Dirscherl/Corbis

Caterpillars create ‘avenue of ghosts’ in Cambridge park

A historic tree-lined path on Jesus Green in Cambridge has become shrouded in spectacular cobweb-like nests created by an infestation of bird cherry ermine moth caterpillars (Yponomeuta evonymella). The larvae make large communal webs for protection then feast on the leaves, sometimes stripping the trees bare.

The clearest lake in the world: Blue Lake, on New Zealand’s South Island

The visibility of distilled water is about 80 metres. Blue Lake, on New Zealand’s South Island, clocks in at 76 metres. Here are the first-ever photos of this newly discovered natural wonder, taken by Klaus Thymann of Project Pressure and supported by New Zealand Department of Conservation and New Zealand Tourism.

Photograph: Klaus Thymann /Project Pressure

White lion breeding at UK wildlife parks linked to ‘canned hunting’.

They are a rare and beautiful variant of an ordinary lion, a big cat with a recessive gene that gives it striking white fur. But two British wildlife parks have been accused of unethical practices for breeding white lions taken from a farm linked to “canned hunting” in South Africa and allowing cubs to be petted for £250 a time.

Photograph: Rhian Grey/Paradise Wildlife Park

Eastern Screech owlets in a tree in Okefenokee Swamp in Georgia, US. From picture desk live: the day’s best news images

Photograph: Graham McGeorge/Barcroft Media

Crop rotation: an aerial view of a field lieing at rest near Eisenhuettenstadt, Germany from picture desk live - the day’s news in pictures

Photograph: Patrick Pleul/Corbis

Pronghorns range over a vast area, from Canada to northern Mexico, seen here on their annual migration, the only time the males and females come together in a mixed-sex herd. From our gallery: Discovery Channel’s North America

Photograph: Discovery Channel

A new species of fairyfly, Tinkerbella nana, has been described by John T Huber of Natural Resources Canada and John S Noyes of London’s Natural History Museum. They named a new genus for the species after the fairy Tinker Bell from JM Barrie’s Peter Pan, while the specific epithet they chose is derived from the name of the children’s dog, Nana, in the same play.

Photograph: Dr John T Huber

A bear stands in front of a steaming geyser in the Valley of the Geysers of Kronotsky Zapovednik, Russia. From this week’s wildlife - in pictures Photograph: Igor Shpilenok/Barcroft Media

Scientists say it is possible that there have never been fewer butterflies in Britain since it was first inhabited by humans due, in part, to the miserable weather of 2012. The orange-tip population (above) dropped by 34%. Habit loss and agricultural intensification mean that many species live in isolated colonies in small nature reserves, making them particularly vulnerable to extinction after adverse weather. Photograph: Butterfly Conservation