GEN-ERIC News

Worker ants accurately gauge their life expectancy, regardless of their actual age, and take on riskier tasks as they feel their days ebbing away. In social insects such as ants, bees and wasps, workers change tasks depending on their age. Older workers do the relatively risky foraging outside the nest, while younger ones engage in safer maintenance tasks within it. By extending the workers’ average life span, this fine-tuning helps to maximise the fitness of the colony. However, no one knew whether the division of labour in ants was activated by age-related physiological changes or through some other mechanism.

A plant-like micro-organism mostly found in oceans could make the manufacture of products, from iridescent cosmetics, paints and fabrics to credit card holograms, cheaper and ‘greener’. The tiny single-celled ‘diatom’, which first evolved hundreds of millions of years ago, has a hard silica shell which is iridescent – in other words, the shell displays vivid colours that change depending on the angle at which it is observed. This effect is caused by a complex network of tiny holes in the shell which interfere with light waves. UK scientists have now found an extremely effective way of growing diatoms in controlled laboratory conditions, with potential for scale-up to industrial level. This would enable diatom shells to be mass-produced, harvested and mixed into paints, cosmetics and clothing to create stunning colour-changing effects, or embedded into polymers to produce difficult-to-forge holograms. Manufacturing consumer products with these properties currently requires energy-intensive, high-temperature, high-pressure industrial processes that create tiny artificial reflectors. But farming diatom shells, which essentially harnesses a natural growth process, could provide an alternative that takes place at normal room temperature and pressure, dramatically reducing energy needs and so cutting carbon dioxide emissions. The process is also extremely rapid – in the right conditions, one diatom can give rise to 100 million descendants in a month.

Many herbal plants such as strawberry, clover, reed and ground elder naturally form networks. Individual plants remain connected with each other for a certain period of time by means of runners. These connections enable the plants to share information with each other via internal channels. They are therefore very similar to computer networks. But what do plants want to chat to each other about? Recently Stuefer and his colleagues were the first to demonstrate that clover plants warn each other via the network links if enemies are nearby. If one of the plants is attacked by caterpillars, the other members of the network are warned via an internal signal. Once warned, the intact plants strengthen their chemical and mechanical resistance so that they are less attractive for advancing caterpillars. Thanks to this early warning system, the plants can stay one step ahead of their attackers. Experimental research has revealed that this significantly limits the damage to the plants.

Twice as many girls as boys are being born in some Arctic villages because of high levels of man-made chemicals in the blood of pregnant women, according to scientists from the Arctic Monitoring and Assessment Programme (Amap). The scientists, who say the findings could explain the recent excess of girl babies across much of the northern hemisphere, are widening their investigation across the most acutely affected communities in Russia, Greenland and Canada to try to discover the size of the imbalance in Inuit communities of the far north. In the communities of Greenland and eastern Russia monitored so far, the ratio was found to be two girls to one boy. In one village in Greenland only girls have been born. The scientists measured the man-made chemicals in women’s blood that mimic human hormones and concluded that they were capable of triggering changes in the sex of unborn children in the first three weeks of gestation. The chemicals are carried in the mother’s bloodstream through the placenta to the foetus, switching hormones to create girl children. Lars-Otto Reierson, executive secretary for Amap, said: “We knew that the levels of man-made chemicals were accumulating in the food chain, and that seals, whales and particularly polar bears were getting a dose a million times higher than that existing in plankton, and that this could be toxic to humans who ate these higher animals. What was shocking was that they were also able to change the sex of children before birth.”

Global warming may carry a higher risk of flooding than previously thought, according to a study released on Wednesday by the British science journal Nature. It says efforts to calculate flooding risk from climate change do not take into account the effect that carbon dioxide (CO2) — the principal greenhouse gas — has on vegetation. Plants suck water out of the ground and “breathe” out the excess through tiny pores, called stomata, in their leaves. Stomata are highly sensitive to CO2. The higher the level of atmospheric CO2, the more the pores tighten up or open for shorter periods. As a result, less water passes through the plant and into the air in the form of evaporation. And, in turn, this means that more water stays on the land, eventually running off into rivers when the soil becomes saturated.