An inspiration from crawl behavior of the earthworm

The target of this research is to obtain valuable inspiration for tissue engineering in nerve regeneration. The effect of topographic feature of plate material surface on the crawl behavior of earthworm was studied. A total of 278 earthworms, with weight 1.2–5.1 g and diameter 2.5–7.0 mm, were divided into three groups (A, B, C) according to their weight. Earthworms always crawl straightly to a certain direction on ground or plate material. When earthworm crawled on the ground surface with regular grooves (straight line or curve with different curvature, depth and width of 3.0–6.0 mm), it was found that (1) earthworm crawled faster on surface with less grooves curvature, fastest on surface with straight grooves and that (2) the earthworm got into grooves easier with less the acute angle between the crawl direction and the grooves. When the earthworm crawled on the plate with different roughness, it was also found that the earthworm crawled much slower on smooth surface, such as glass, than on rough surface, such as cement plate, without calendering. We thought that, in point of the effect of the surface topographic feature of contacting materials, there may be some analogy between crawl behavior of the earthworm and the nerve growth of mammal.