Research Fellows Directory
Dr Swidbert Ott
University of Leicester
Locust swarms are notorious for the periodic devastation they wreak on agriculture in a region stretching from West Africa to India. The key to this problem is that they can change between two dramatically different forms, only one of which is configured for a life in migratory swarms. When population densities are low, locusts occur as inconspicuous and well-camouflaged solitary animals that actively avoid one another. Hunger may, however, force them together in the search for food, and the very proximity to other locusts triggers a radical makeover. After only a few hours, the locusts behave much more actively and, critically, their usual aversion for one another gives way to attraction. Thus, they aggregate into ever bigger mobile groups — the beginnings of a swarm. The constant crowding then drives slower changes in many other characters including colour and body shape. The end result of this Jekyll-to-Hyde process is a brightly coloured pest that was mistaken for a separate species until the 1920s.
My aim is to identify the mechanisms by which this remarkable transformation occurs. In a recent breakthrough, we have discovered that the switch to gregarious behaviour is caused by a surge in serotonin in the brain. In humans, serotonin plays an important role in controlling our mood and interactions with the world. Like anxiety or depression in humans, phase change in locusts is a syndrome that affects many aspects of behaviour; builds on a genetic predisposition but is triggered by the environment; and affects social interactions that in turn feed back on the individual. Locusts have much simpler brains, but these follow the same principles as those of higher animals. Understanding these principles in locusts thus sheds light on how very different behavioural types arise from the interplay between the genome (“nature”) and the environment (“nurture”). Ultimately, this will help develop more targeted control methods that prevent the formation of swarms.