Scientists discover what makes locusts swarm
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CTA. 1996. Scientists discover what makes locusts swarm. Spore 62. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/47305
A chemical sometimes found in the foam that surrounds locust eggs could provide a key to locust control. The chemical is responsible for the young turning into gregarious locusts: when the chemical is not present, locusts will hatch as solitary...
A chemical sometimes found in the foam that surrounds locust eggs could provide a key to locust control. The chemical is responsible for the young turning into gregarious locusts: when the chemical is not present, locusts will hatch as solitary insects. This finding comes from recent research at Oxford University, UK. Dr Stephen Simpson and his colleagues have found that the stimulus to producing this chemical is crowding. After rains, a flush of vegetation will attract the solitary locusts, which are living in the locality and, as the vegetation is devoured, the locusts tend to crowd closer and closer together. Once they start rubbing up against each other, the females are stimulated to produce a chemical which they add to the foam that is produced to protect the eggs as they are laid into the soil. The chemical acts on the embryos as they develop in the eggs and switches on the genes which are responsible for turning a locust from being solitary into a gregarious insect. All the young hatch as gregarious locusts which is the key to the locust's importance as a pest: if it did not make that change then it would not become a pest. The researchers at Oxford found that just four hours crowding was sufficient to stimulate the females into producing the chemical. The work at Oxford complements the findings from ICIPE, the International Centre for Insect Physiology and Ecology in Nairobi, Kenya (see Spore 61 p12). The Oxford scientists have found the crucial factor that triggers mass swarming, while the ICIPE work has identified the pheromones that maintain mass egg laying and keep the swarms together. With that knowledge the two research establishments can move forward to develop ways to disrupt these crucial phases of the life cycle, leading to the development of a long term control strategy against this age-old pest. Department of Zoology University of Oxford South Parks Road, Oxford OX1 UPS, UK