New sex drug turns locusts solo

Insect specialists have isolated a pheromone that locusts emit when they want to be left alone to mate, which could prove an effective new weapon against this destructive species.

Whilst the pheromone is clearly useful to the species when they are in their winged mature state, its impact on adolescent wingless ‘hopper’ locusts makes them vulnerable, says the International Centre for Insect Physiology and Ecology (ICIPE). It says that spraying the pheromone (phenylacetonitrile, or PAN), in tiny quantities of 10 millilitres per hectare can stop marauding armies of hoppers.These pests march in bands five kilometres wide given the right conditions – eating their own body-weight in vegetation daily.Tests showed that PAN caused the insects to resume a solitary behaviour common to non-swarming locusts.A UN Food & Agriculture Organisation note said: “Confused and disoriented, some lost their appetite altogether, while others turned cannibal and ate one another. Any survivors were easy prey for predators.”