据国外媒体报道,最新研究表明蜘蛛是世界上对振动最敏感的生物之一,仅次于蟑螂。处于饥饿之中的蜘蛛对振动的敏感性更为强烈,可以探察到最安静的移动和气流变化,以及接近无法探测到的振动。
这项最新研究发表在英国皇家学会《界面》期刊上,事实上蜘蛛的整个身体是一个敏感体,可以探测到所在路径的任何事物。世界知名蜘蛛研究专家弗列德里-巴斯是该研究合著作者,他说:“蜘蛛身体上不同区域内嵌着超过3000个应变传感器,但多数位于腿部和复合器官上,例如邻近腿部关节的振动接收体。”
巴斯和研究负责人奥地利维也纳大学神经生物学家克莱门斯-沙伯,以及基尔大学同事斯坦尼斯拉夫-古珀共同完成这项研究工作,他们使用白光干涉法来首次测试蜘蛛复杂的微力学变化,这一过程结合了光学仪器的光波,从而能够探测到这种小动物非常精确的移动变化,例如蜘蛛应变传感器上的作用力。蜘蛛的应变传感器上包含着可接收本地移动的琴形器官微型分叉,科学家能够以纳米等级测量分叉的敏感性,发现伴随着振动减弱,分叉的敏感性也相应减弱。
沙伯和研究同事是对一只成年雌性大型中美流浪蛛进行研究的,它的体积和令人印象深刻的捕猎才能,非常适合于科学家研究蜘蛛的习性,并且此前也曾对该物种研究过。沙伯说:“我们的蜘蛛通过植物叶片接受振动,通过植物和蜘蛛网传递的振动,如果是生物等级活动特征,蜘蛛就会发动攻击。如果振动源显示不是猎物参数信息,蜘蛛就会不发动攻击或者逃跑。”
因此蜘蛛可能探测到人类或者其它动物的存在,但除非这些侵入者活动类似于典型的猎物,蜘蛛是不会发起攻击的。基于这样敏感的探测能力,蜘蛛经常将时间用于没有意义的狩猎中,这与它们的敏感接受信息信息不相符合。近期美国辛辛那提大学生物学家乔治-尤兹和同事希拉-戈登研究蜘蛛习性发现,当一些蜘蛛物种想要交配时,会发出一种独特的性吸引振动,通常是在落叶上发出振动来吸引异性关注。蜘蛛的敏感探测能力并不受喧闹环境的干扰影响。
如果一只蜘蛛未“探测”到你的存在,事实上它可能是已从视觉、嗅觉或者味觉上察觉到你。沙伯解释称,蜘蛛拥有很好的视力,且对低亮度物体保持敏感性,但除了低瞬间分辨率条件下。在蜘蛛触须上一种叫做“须肢”的微型化学感应毛发传感器还可接收气体,雌性蜘蛛可释放一种特殊的费洛蒙香味来吸引雄性。蜘蛛还有更多的奇特习性,通过这些独特功能可以帮助科学家来研制新型装置,用于医学、军事、商业和其它潜在产业应用。(生物谷 Bioon)
doi:10.1098/rsif.2011.0565
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Force transformation in spider strain sensors: white light interferometry
Schaber, Clemens F.; Gorb, Stanislav N.; Barth, Friedrich G.
Scanning white light interferometry and micro-force measurements were applied to analyse stimulus transformation in strainsensors in the spider exoskeleton. Two compound or ‘lyriform’ organs consisting of arrays of closely neighbouring, roughlyparallel sensory slits of different lengths were examined. Forces applied to the exoskeleton entail strains in the cuticle,which compress and thereby stimulate the individual slits of the lyriform organs. (i) For the proprioreceptive lyriform organHS-8 close to the distal joint of the tibia, the compression of the slits at the sensory threshold was as small as 1.4 nmand hardly more than 30 nm, depending on the slit in the array. The corresponding stimulus forces were as small as 0.01 mN.The linearity of the loading curve seems reasonable considering the sensor's relatively narrow biological intensity rangeof operation. The slits' mechanical sensitivity (slit compression/force) ranged from 106 down to 13 nm mN?1, and gradually decreased with decreasing slit length. (ii) Remarkably, in the vibration-sensitive lyriform organ HS-10 onthe metatarsus, the loading curve was exponential. The organ is thus adapted to the detection of a wide range of vibrationamplitudes, as they are found under natural conditions. The mechanical sensitivities of the two slits examined in this organin detail differed roughly threefold (522 and 195 nm mN?1) in the biologically most relevant range, again reflecting stimulus range fractionation among the slits composing the array.