biology

Slippery Coating Makes Snake Bellies Slither

Fatty layer covering snakeskin protects animal’s underside against scrapes and wear.

Snakes can slither smoothly over almost any surface, from jungle branches to desert sands, without damaging their skin – an ability that has fascinated researchers.

“How can snakes move across very harsh and abrasive environments and still have belly skin that is shiny and smooth?” asked Stanislav Gorb, who studies biomechanics at the University of Kiel in Germany. “Is it the material the scales are made of? The tiny microstructures on them? The molecules they are coated with?”

Gorb and his collaborators have performed research exploring many of these questions. They are presenting it this week at a meeting known as the AVS International Symposium and Exhibition in San Jose, California. Read more in Inside Science.

Fungi borrowed bacterial gene again and again

Multiple independent gene transfers gave fungi ability to colonize plant roots.

A single gene from bacteria has been donated to fungi on at least 15 occasions. The discovery shows that an evolutionary shortcut once thought to be restricted to bacteria is surprisingly common in more complex, eukaryotic life.

Bacteria frequently trade genes back and forth with their neighbours, gaining abilities and traits that enable them to adapt quickly to new environments. More complex organisms, by contrast, generally have to make do with the slow process of gene duplication and mutation. Read more in Nature.

Male scent stimulates female goats’ fertility

Current Biology, Murata et al.

Current Biology, Murata et al.

Single pheromone found to induce ovulation.

The distinctive aroma of goats does more than just make barnyards extra fragrant. Male goats can use their heady scent to make female goats ovulate simply by being near them.

Researchers had ascribed this ‘male effect’ to chemicals known as primer pheromones — a chemical signal that can cause long-lasting physiological responses in the recipient. Examples of primer pheromones are rare in mammals; the male effect in goats and sheep, and a similar effect in mice and rats, where the presence of males can speed up puberty in females, are the only known cases. But exactly what substances are at work and how has remained a mystery. Read more in Nature.

Why fruitflies know their beer

Competing neuronal pathways help adults to choose locations with just the right amount of alcohol for their offspring to thrive.

Fruitflies know exactly how much alcohol will be good for their young. Larvae living on a food source with the right concentration of ethanol will grow into heavy, healthy adults and will be protected against parasites — which explains why the insects are attracted to rotting fruit or the crate of empty beer bottles in your kitchen but not to the vodka or gin.

Now researchers have uncovered the neural mechanism that allows the fruitfly Drosophila melanogaster to choose the best place to lay its eggs. Read more in Nature.

Pesticide makes invading ants suicidally aggressive

Neonicotinoids change behaviour in ways that could affect spread of invasive species.

Neonicotinoid insecticides have developed a bad reputation for their unintended and potentially harmful effects on pollinating insects such as bees. A study in New Zealand now shows that the chemical can also change how native and invasive ants interact.

New Zealand is facing an invasion of Argentine ants (Linepithema humile), which compete with native southern ants (Monomorium antarcticum). The insects often meet in urban or agricultural areas, where neonicotinoids are in use. So ecologist Rafael Barbieri, a graduate student in the lab of Philip Lester at Victoria University of Wellington, wondered whether the behavioural changes that have been associated with sublethal neonicotinoid exposure in other insects affect how the two species interact. Read more in Nature.

Cultured follicles offer hope for beating baldness

Old cell-growth method moves hair restoration technique from mice to humans.

Life seemed to be unfair to balding people. More than four decades ago, scientists found a way grow hair follicles in hairless rodents by cultivating skin cells in a dish and implanting them under the skin. But when they tried the same thing in humans, it never worked. Now, a simple tweak to the culturing technique shows that there might be hope for countering baldness. Read more in Nature.

Bats use ear trumpets for social calls

Mammals roost in megaphone-shaped leaves that amplify calls from friends.

Bats that nest inside curled-up leaves may be getting an extra benefit from their homes: the tubular roosts act as acoustic horns, amplifying the social calls that the mammals use to keep their close-knit family groups together.

South American Spix’s disc-winged bats (Thyroptera tricolor) roost in groups of five or six inside unfurling Heliconia and Calathea leaves. The leaves remain curled up for only about 24 hours, so the bats have to find new homes almost every day, and have highly specialized social calls to help groups stay together. When out flying, they emit a simple inquiry call. Bats inside leaves answer with a more complex response call to let group members know where the roost is. Read more in Nature.

Amorous insects predict the weather

Changes in atmospheric pressure reduce mating in beetles, moths and aphids.

People have long claimed that animals can predict the weather, for examply by curtailing their activity when rain threatens. Such theories have had little evidence to support them, but now, a team of scientists has found a concrete example: insects shy away from sex in response to the drop in atmospheric pressure that presages rain. Read more in Nature.

Silver makes antibiotics thousands of times more effective

Ancient antimicrobial treatment could help to solve modern bacterial resistance.

Like werewolves and vampires, bacteria have a weakness: silver. The precious metal has been used to fight infection for thousands of years — Hippocrates first described its antimicrobial properties in 400 bc — but how it works has been a mystery. Now, a team led by James Collins, a biomedical engineer at Boston University in Massachusetts, has described how silver can disrupt bacteria, and shown that the ancient treatment could help to deal with the thoroughly modern scourge of antibiotic resistance. The work is published today in Science Translational MedicineRead more in Nature.