Poor Mojo's Newswire

Cyprian honeybees will swarm together around a threatening hornet, forming a tightly-packed ball that kills the would-be-invader, but exactly how this happened was unknown. Now – by a process of elimination – a study suggests that the honeybees kill by depriving their enemy of oxygen.

Hornets are particularly nasty predators and will chop off the head of a bee before carrying it back to their nest to eat. Often greedy hornets will go so far as to invade the honeybee hive to obtain food such as larvae. "They can slaughter whole colonies in a few hours," says Alexandros Papachristoforou of the Aristotle University of Thessaloniki in Greece.

One plausible reason is that early hominins suddenly stumbled on a new, rich food source capable of fuelling a large, energetically expensive brain. For many years, anthropologists presumed the crucial food source was meat, which became more accessible as our ancestors began to use stone tools for hunting or cutting. More recently, however, others have proposed an alternative - starchy tubers. Proponents of this view argue that early hominins had teeth better suited to grinding plant matter than tearing flesh. Recent studies of isotope ratios in hominin fossils also suggest a plant-rich diet.

The males advertise their prowess and impress potential mates by stealing papaya from local farms, researchers found.

Edinburgh University's Royal Dick Vet School staff have carried out extensive research into the disease, which kills about 55,000 people per year.

If enough domestic dogs are vaccinated, worldwide the disease cycle could be broken leaving no threat to humans.

Pulling a fist-sized kidney through the tiny, semicircular hole involves a mixture of compressing the organ and distending the incision, says Jeffrey Cadeddu of Southwestern Medical Center in Dallas, Texas, who carried out the operation. "We place the kidney in a plastic sack like a ziplock, which is compressed as we pull it through the incision," he says. "Also, the skin stretches quite a bit."

So far Cadeddu has performed the procedure on three people: two with kidney infections and one with a cancerous kidney.

The icy coatings could help make diamond-toughened medical implants more biocompatible, according to the Harvard University team who carried out the work.

Thin diamond coatings are found in a growing number of wear-resistant medical implants, such as prosthetics, artificial heart valves and joint replacements. However, diamond can causes clotting by attracting coagulating proteins. Also, its hardness often results in more tissue abrasion than with other implant materials. Ice could lessen these effects by offering a biocompatible interface of water molecules.