Sizing Up, Behaviour: cold-blooded animals (commended)
A scattering of gecko droppings on the sunny veranda of Klaus’s holiday apartment near Etang-Sale-les- Hauts, on the French island of Réunion, had attracted some unusual-looking insects. They were neriid longlegged flies. Klaus settled down with his camera to watch as they interacted.
“Every so often, a couple of males would take a break from feeding and engage in a kind of combat dance that involved spinning around each other,” he says. “They would finish by stretching up to their full one and a half centimetres, then pushing with their mouthparts, shoulders and forelegs until one gained height, before flying away or mating with nearby females. I was so impressed by the harmony in the combat dance that I ended up photographing them for several hours.”
Photograph by Martin Oeggerli, National Geographic
Dryas iulia
Perched on the tendril of a Passiflora plant, the egg of the Julia heliconian butterfly may be safe from hungry ants. This species lays its eggs almost exclusively on this plant’s twisted vines.
“The sun had just come out after a brief shower of rain and caught the water droplets on this golden orb spider web at just the right angle to make her look even more spectacular as usual,” says Brad Warland.
Photo Credit: Brad Warland
There is obviously no love in the jumping spider species world, and competition for food is top priority. This one a female Green Jumping Spider. The poor little spider in her mouth, I had shot earlier, and watched in horror as he was consumed by the bigger spider, leading me to conclude that the larger is a ‘Big Meanie’.” Photograph by Flickr user AdamNoosa.
THOUGH SPIDERS MAY SEEM safe in their nets, they can often fall prey to marauding ants. But thegolden orb web spider (Nephila antipodiana) has a secret weapon: a chemical repellent to ward off ant attackers.
Researchers from the University of Melbourne and National University of Singapore (NUS) have discovered the chemical, which is spun into the spiders’ silk, is a type of natural insect repellent. The find could pave the way for a new insect repellent for humans.
“This study is among the first to show animals incorporating a chemical defence as a response to the threat of predation,” says Professor Mark Elgar of the University of Melbourne’s department of zoology. “It is particularly interesting that this only occurs in spiders that are large enough, and therefore spin silk that is thick enough, to expose them to this risk of ant invasion.”
Adelaide museum
A century old mystery has been solved by a new study showing how butterflies mimic the wing patterns of other species to escape being eaten by birds. The study is published today in the international journal Nature.
Dr Siu Fai (Ronald) Lee from the Department of Genetics and Bio21 Institute, University of Melbourne, travelled to the UK to join the research team, led by scientists at CNRS (Muséum National d’Histoire Naturelle, Paris) and the University of Exeter (UK).
Researchers studied the Amazonian butterfly Heliconius numata to understand how it imitates other species with an equally unpleasant taste. This trick is known as Müllerian mimicry; a predator that has learned to avoid an organism with certain markings, will avoid all similar-looking species.
