To Cope With the Chaos of Swarming, Locusts Enlarge Their Brains

By Andrew Moseman | May 26, 2010 9:58 am

locustsThe single-mindedness that drives a swarm of locusts to rampage through the countryside and devour everything in its path might not seem like it would require a great deal of brainpower. However, biologists in Britain have found that the brain of a swarming locust swells up to 30 percent larger than the brain of its solitary counterparts.

These crazed grasshoppers aren’t geniuses, says lead researcher Swidbert Ott. According to his study forthcoming in the Proceedings of the Royal Society B, swarming locusts simply need enlarged brains to cope with the assault on their senses that comes with being caught up in an insect mob:

Locust brains are quite simple: on each side of the head is an optic lobe taking in information from the eyes and performing basic processing, and these lobes feed into the central midbrain, which carries out higher-level processing.

In swarming locusts, the midbrain grew more than the optic lobes. This, and other subtle changes, suggest that because swarming locusts are constantly surrounded by wild activity, they do not need to worry about having particularly sensitive vision. However, they do need extra high-level processing power to cope with the extremely complex patterns of motion that they see [New Scientist].

Locusts need this improved brainpower to survive, because despite the fact that they travel in these legendary hordes like a plague ordered from on high, the truth is that they don’t much care for each other. In good times, locusts are solitary; they gather into swarms when they need to seek out new vegetation to survive. Says Ott:

”Their bigger and profoundly different brains may help swarming locusts to survive in the cut-throat environment of a locust swarm…. Who gets to the food first wins, and if they don’t watch out, they themselves become food for other locusts” [The Telegraph].

The suddenness with which locusts change behavior and even appearance when they go on the march has long fascinated Ott and his team.

Dr Ott and his team had previously shown that a signalling chemical in the brain, called serotonin, was crucial in this sudden change in the insects’ behaviour – causing a solitary creature to become part of this frenzied swarm. When this sudden behavioural change happens, the locusts also (much more gradually) change in colour and even body shape [BBC News].

Related Content:
DISCOVER: Cannibalism: The Animal Kingdom’s Dirty Little Secret (photo gallery)
DISCOVER: Locust Plague Sweeps Across Africa
DISCOVER: Hunger on the Wing
80beats: Serotonin Changes Locusts from Shy Loners to Swarming Pests

Image: Tom Fayle

  • john eastman

    after recently watching a show on locust swarms i became intrigued by a possible solution to this profound menace. the scientist quoted stated the current eradication efforts, eg: arial pesticides, are ineffective and may do more harm thangood to the enviroment. there may be a technical solution to this problem. in the iraq war the u.s. army deployed a device called an ” active denial system” its a nonlethal millimeter wave weapon. it funtions basically like a microwave oven with the ability to be focused at a given area. its used as crowd control to slightly boil skin and induce hostile crowds to disperse. it has also been deployed at international summits. its very powerfull and can actually boil internal organs. perhaps this device can be adapted to be used against insect swarms and mounted to helicopter to cook these pest. it could be tested against the ” mormon cricket” in utah. we could also offer our help in mexico to eradicate locust swarms before they cause billions of dollars in agriculture losses in the u.s. i think mexico would welcome and benefit from such assistance. we could also deploy the device wherever these insects are hatching.


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