沙漠蝗蟲平時喜歡單獨生活,，但有時也會成群結隊地遷徙,，形成遮天蔽日的蝗災,。
英國一項最新研究發(fā)現(xiàn),，成群結隊的蝗蟲與單獨生活的蝗蟲相比大腦要大出很多,，這說明群體生活方式會對生物的腦結構產(chǎn)生顯著影響。研究人員抓捕了一些群聚的蝗蟲,，將它們分開單獨飼養(yǎng)并培育到第三代,，然后對群聚和獨居兩種狀態(tài)下蝗蟲的大腦進行成像分析。結果顯示,，群聚蝗蟲的大腦比獨居蝗蟲的大腦要大出30％,。
分析還顯示，雖然是同一物種,，但兩種狀態(tài)下蝗蟲大腦中不同功能部位的比例也發(fā)生了變化,。獨居蝗蟲大腦中有關視覺和嗅覺部位的比例相對較大，這有利于它們探測環(huán)境信息；而群聚蝗蟲的大腦中與學習和處理復雜信息相關的部位較大,。
進行這項研究的奧特博士說,，群聚狀態(tài)下蝗蟲大腦發(fā)生的顯著變化與其生存環(huán)境有關，蝗蟲通常在缺乏食物的情況下才成群結隊地遷徙,，其中的單個蝗蟲處于高度競爭性的環(huán)境中,，在搶占食物的同時還需要提防自己成為其他蝗蟲的口中餐。他說,，這種群體生活帶來的挑戰(zhàn)也許可以幫助解釋為什么許多群居的脊椎動物都進化出特別大的大腦,。
研究報告發(fā)表在新一期英國《皇家學會學報B》上。（生物谷Bioon.com）
生物谷推薦原文出處：
Proceedings of the Royal Society B:Biological Sciences doi: 10.1098/rspb.2010.0694
Gregarious desert locusts have substantially larger brains with altered proportions compared with the solitarious phase
Swidbert R. Ott* and Stephen M. Rogers
Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
The behavioural demands of group living and foraging have been implicated in both evolutionary and plastic changes in brain size. Desert locusts show extreme phenotypic plasticity, allowing brain morphology to be related to very different lifestyles in one species. At low population densities, locusts occur in a solitarious phase that avoids other locusts and is cryptic in appearance and behaviour. Crowding triggers the transformation into the highly active gregarious phase, which aggregates into dense migratory swarms. We found that the brains of gregarious locusts have very different proportions and are also 30 per cent larger overall than in solitarious locusts. To address whether brain proportions change with size through nonlinear scaling (allometry), we conducted the first comprehensive major axis regression analysis of scaling relations in an insect brain. This revealed that phase differences in brain proportions arise from a combination of allometric effects and deviations from the allometric expectation (grade shifts). In consequence, gregarious locusts had a larger midbrain∶optic lobe ratio, a larger central complex and a 50 per cent larger ratio of the olfactory primary calyx to the first olfactory neuropile. Solitarious locusts invest more in low-level sensory processing, having disproportionally larger primary visual and olfactory neuropiles, possibly to gain sensitivity. The larger brains of gregarious locusts prioritize higher integration, which may support the behavioural demands of generalist foraging and living in dense and highly mobile swarms dominated by intense intraspecific competition.
