Mechanical properties of the antlion larva Euroleon nostras (Neuroptera, Myrmeleontidae) jaws correlate with the amount of inorganic content

Abstract

AbstractThe diversity of insects can be explained by their ability to establish various ecological niches, which includes the foraging from diverse sources. The cuticle-based feeding structures interact with the food and show adaptations in shape, material composition and mechanical properties to it. Some predatory species are extremely specialised to a very narrow spectrum of prey. In this study, we focus on the mouthparts of a very prominent ambush predator, the antlion larvae ofEuroleon nostras. By nanoindentation, we tested the hardness and the Young’s modulus of the mouthparts, which are significantly harder and stiffer than other insect cuticle structures. To gain insight into the origins of the high values, we studied the degree of tanning using confocal laser scanning microscopy and determined the content of inorganic elements by energy dispersive spectroscopy. We could correlate the proportions of the transition metals and alkaline earth metals with the mechanical property values. We also conducted experiments on the breaking stress, the puncturing and biomechanical behaviour of the jaws, which highlighted their extraordinary strength. These findings are not only valuable for biologists, but also for material scientists, as they contribute to our understanding of the origins of mechanical property heterogeneities in insect cuticle.