National Institute for Material Science, Hybrid Materials Center, Functional Interconnection Group, Tsukuba, Ibaraki, Japan.
Proc Biol Sci. 2011 Jun 7;278(1712):1748-52. doi: 10.1098/rspb.2010.1772. Epub 2010 Nov 10.
In insects, cleaning (grooming) of tarsal attachment devices is essential for maintaining their adhesive ability, necessary for walking on a complex terrain of plant surfaces. How insects obtain information on the degree of contamination of their feet has remained, until recently, unclear. We carried out friction force measurements on walking beetles Gastrophysa viridula (Coleoptera, Chrysomelidae) and counted grooming occurrence on stiff polymer substrata with different degrees of nanoroughness (root mean square: 28-288 nm). Since nanoscopically, rough surfaces strongly reduced friction and adhesion without contaminating feet, we were able to demonstrate, for the first time to our knowledge, that friction force between tarsal attachment pads and the substrate provides an insect with information on the degree of contamination of its attachment structures. We have shown that foot grooming occurrence correlates not only with the degree of contamination but also with the decrease of friction force. This result indicates that insects obtain information about the degree of contamination, not statically but rather dynamically and, presumably, use mechanoreceptors monitoring either tensile/compressive forces in the cuticle or tensile forces between leg segments.
在昆虫中，跗节附着装置的清洁（梳理）对于维持其粘性能力至关重要，这对于在植物表面的复杂地形上行走是必要的。直到最近，昆虫如何获得关于其脚部污染程度的信息仍然不清楚。我们对行走甲虫 Gastrophysa viridula（鞘翅目，叶甲科）进行了摩擦力测量，并在具有不同纳米粗糙度（均方根：28-288nm）的硬聚合物衬底上计算了梳理发生的次数。由于从纳米尺度上看，粗糙表面强烈降低了摩擦力和附着力，而不会污染脚部，因此我们首次能够证明，就我们所知，跗节附着垫与基质之间的摩擦力为昆虫提供了关于其附着结构污染程度的信息。我们已经表明，脚部梳理发生的次数不仅与污染程度相关，还与摩擦力的降低相关。这一结果表明，昆虫不是静态地而是动态地获取关于污染程度的信息，大概是通过监测表皮中的拉伸/压缩力或腿节之间的拉伸力的机械感受器来获取信息。
