Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA.
Department of Energy Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, 53726, USA.
Nat Commun. 2020 Nov 24;11(1):5792. doi: 10.1038/s41467-020-19566-3.
Although calcareous anatomical structures have evolved in diverse animal groups, such structures have been unknown in insects. Here, we report the discovery of high-magnesium calcite [CaMg(CO)] armor overlaying the exoskeletons of major workers of the leaf-cutter ant Acromyrmex echinatior. Live-rearing and in vitro synthesis experiments indicate that the biomineral layer accumulates rapidly as ant workers mature, that the layer is continuously distributed, covering nearly the entire integument, and that the ant epicuticle catalyzes biomineral nucleation and growth. In situ nanoindentation demonstrates that the biomineral layer significantly hardens the exoskeleton. Increased survival of ant workers with biomineralized exoskeletons during aggressive encounters with other ants and reduced infection by entomopathogenic fungi demonstrate the protective role of the biomineral layer. The discovery of biogenic high-magnesium calcite in the relatively well-studied leaf-cutting ants suggests that calcareous biominerals enriched in magnesium may be more common in metazoans than previously recognized.
虽然钙质解剖结构已经在不同的动物群体中进化，但在昆虫中尚未发现此类结构。在这里，我们报告了在切叶蚁 Acromyrmex echinatior 的主要工蚁的外骨骼上发现了高镁方解石 [CaMg(CO)] 盔甲的发现。活体饲养和体外合成实验表明，随着蚂蚁工蚁的成熟，生物矿化层迅速积累，该层连续分布，几乎覆盖整个表皮，并且蚂蚁表皮外膜催化生物矿化核的形成和生长。原位纳米压痕表明生物矿化层显著增强了外骨骼的硬度。在与其他蚂蚁的激烈交锋中，具有生物矿化外骨骼的蚂蚁工蚁的存活率增加，并且感染昆虫病原真菌的风险降低，这证明了生物矿化层的保护作用。在相对研究充分的切叶蚁中发现了生物成因的高镁方解石表明，富含镁的钙质生物矿化可能比以前认为的更为普遍。
