THE ARRANGEMENT of blood vessels in our heads may act as a heat exchanger to cool blood before it enters the brain, and a failure of this system may be a cause of cot death, according to British scientists. A team at the Institute of Neurology in London investigated the temperature of monkeys' carotid artery blood. This was lower than brain tissue temperatures, suggesting that incoming blood helps cool the active brain.
If that function fails in a baby, the team suggests, cot death may follow. But the work was described as "far from proven" by other researchers.
PROMISCUITY IS healthy if you are a queen bee, say scientists who believe they have discovered why female bees may mate with up to 20 males in their nuptial dance. A study into the mating habits of the bumblebee found that sex with multiple partners improves the ability of subsequent generations to ward of parasites and infectious diseases.
The researchers artificially inseminated queen bumblebees with sperm of either high or low genetic diversity - to mimic the effects of mating with many males - and exposed the resulting colonies to parasites. They found that colonies from highly diverse sperm were less likely to suffer parasitic attack, which supports the general view that genetic diversity is a way of keeping pace with the continual arms race between parasites and their host organisms.
Two Swiss scientists at ETH Zurich concluded that sex with multiple partners strengthens offspring against parasites and disease. Writing in the journal Nature, they said: "Colonies headed by queens inseminated by highly diverse sperm had lower intensities of infection and lower prevalence of infection, as compared with colonies with low genetic diversity, by both of the major parasites seen in our area of Switzerland."
Charles ArthurReuse content