Effect of Asymmetry in the Wing Vein Network

Abstract

A wing vein network of a fore wing of a Drosophila fly has asymmetry. One vein breaking symmetry of the wing vein network was found via application of our topological transformation. This asymmetry-creating wing vein can be a strategy to improve functionality of the wing veins. As one of multiple functions of the wing veins, they are pipes to transport blood according to the entomological knowledge. However, there have been no engineering attention to the function of vein network as pipe network for blood transportation and are no understandings of how blood circulation is achieved in such a network consisting of extremely narrow pipes based on physics. In this study, we revealed the effect of the asymmetric vein network structure on the blood circulation via comparison with symmetric vein network without the asymmetry-creating vein. A numerical simulation based on the Hardy-Cross method allowed us to demonstrate how addition of this vein influences blood circulation in the wing. The result of that showed the asymmetrical structure improves blood flow distribution in the posterior region of the wing and energy consumption by pumping organ for circulation. Our results interpreted importance of the asymmetry caused by one irregularly positioned vein for the efficient maintenance of the wing via circulation.