Biologists identify nerve cells that make locusts form gangs

Posted by ap507 at Dec 17, 2014 12:50 PM |
Biologists from Universities of Leicester and Sydney reveal behavioural changes in locusts through serotonin-producing cells
Biologists identify nerve cells that make locusts form gangs

Portrait of a Desert locust, with a view of the brain (yellow) within the head; the brain image was obtained by computer-assisted laser scanning microscopy. © University of Leicester

A team of biologists has identified a set of nerve cells in desert locusts that bring about ‘gang-like’ gregarious behaviour when they are forced into a crowd.

Dr Swidbert Ott from the Department of Biology, working with Dr Steve Rogers at the University of Sydney, Australia, has published a study that reveals how newly identified nerve cells in locusts produce the neurochemical serotonin to initiate changes in their behaviour and lifestyle.

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Computer reconstruction of nerve cells in a desert locust that produce the neurochemical serotonin. The yellow cells increase their serotonin content within an hour of exposing a locust to any of the social stimuli that induce gregarious behaviour. © University of Leicester
Locusts are normally shy, solitary animals that actively avoid the company of other locusts. But when they are forced into contact with other locusts, they undergo a radical change in behaviour – they enter a ‘bolder’ gregarious state where they are attracted to the company of other locusts. This is the critical first step towards the formation of the notorious locust swarms.

Dr Ott said: “Locusts only have a small number of nerve cells that can synthesise serotonin.  Now we have found that of these, a very select few respond specifically when a locust is first forced to be with other locusts. Within an hour, they produce more serotonin.

“It is these few cells that we think are responsible for the transformation of a loner into a gang member. In the long run, however, many of the other serotonin-cells also change, albeit towards making less serotonin.” 

Serotonin has important roles in the brains of all animals that include the regulation of moods and social interactions. 

In humans, there are strong links between changes in serotonin and mental disorders such as depression and anxiety.

The paper, ‘Differential activation of serotonergic neurons during short- and long-term gregarization of desert locusts’, published in the academic journal Proceedings of the Royal Society B: Biological Sciences, can be found here.

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