Laboratory of Bio-Design, Department of Agricultural Innovation for Sustainable Society, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa, 243-0034, Japan.
NanoSuit Inc., 1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192, Japan.
Sci Rep. 2023 Aug 31;13(1):14335. doi: 10.1038/s41598-023-41474-x.
Numerous studies have focussed on the mechanisms of entry of pesticides into insect body parts such as oral intake, penetration through the integument of the body wall, and inhalation through spiracles. However, little is known about how insecticides spread to the points of entry or the paths on the body surface that are used to reach the target sites. In this study, elemental signals of pesticide-mimicking test solutions were tracked and their routes of spreading in experimental insects (Blattella germanica L.) were investigated using NanoSuit (a method of surface modification) and energy dispersive X-ray spectroscopy, combined with high-resolution scanning electron microscopy. When the test solution initially adhered to the dorsal and/or ventral body surface, it tended to spread horizontally to reach lateral plates. Whereas, when the solution directly adhered to the anterior side of the lateral plates, it spread to posterior segments. In this case, however, spreading in the opposite direction (i.e., the solution directly adhered to the posterior side of the lateral plates) was interrupted at a boundary erected by different groups of fine structures; each protrusion was large, and the arrangement was rather dense in the posterior segments. Morphological features of these fine structures and chemical characteristics of the hydrophobic surface substances potentially regulate the strength of the capillary force, which determines pesticide spreading.
许多研究都集中在杀虫剂进入昆虫身体部位的机制上，如口服摄入、穿透体壁的表皮和通过气门吸入。然而，对于杀虫剂如何传播到进入点或用于到达靶位的体表路径，人们知之甚少。在这项研究中，使用 NanoSuit（一种表面修饰方法）和能量色散 X 射线光谱结合高分辨率扫描电子显微镜，跟踪了模拟农药测试溶液的元素信号，并研究了其在实验昆虫（德国小蠊）中的传播路径。当测试溶液最初附着在虫体的背部和/或腹部表面时，它往往会横向扩散以到达侧板。然而，当溶液直接附着在侧板的前侧时，它会扩散到后段。然而，在这种情况下，在相反方向上的扩散（即，溶液直接附着在侧板的后侧）在由不同组的精细结构竖立的边界处被中断；每个突起都很大，在后段的排列相当密集。这些精细结构的形态特征和疏水性表面物质的化学特性可能调节着决定杀虫剂扩散的毛细作用力的强度。
