Why do darkling beetles do so well in the Namib Desert?
The Namib – a coastal desert that stretches for 2,000km along the south-west coast of Africa – is one of the driest habitats on Earth. Survival here depends on finding and retaining water.
Water loss is a key ecological constraint for many small insects, which rapidly lose vapour through the breathing tubes on each body segment, particularly during flight. Beetles, however, equipped with tight-fitting wingcases, are better able to combat this. In any case, many Namibian darklings have given up on flying – their wingcases are fused together, further improving vapour insulation.
Darklings have also adapted their behaviour to life in the desert. They avoid the heat of the day by scavenging on dead animal and plant material after sunset, and are adept at finding moisture via a strategy known as ‘fogbasking’. Scaling the dunes in the early morning, the beetles tip their tails into the air to harness the mist blowing onshore from the Atlantic, which condenses on their bodies. When a droplet is large enough, it trickles down water-repellent grooves towards