Material composition of the endophytic ovipositor in the damselfly Calopteryx splendens (Odonata, Calopterygidae)

Matushkina, N., Gorb, S. N., & Krings, W. (2025). Material composition of the endophytic ovipositor in the damselfly, Calopteryx splendens (Odonata, Calopterygidae). Journal of Insect Physiology, 163, 104813. https://doi.org/10.1016/j.jinsphys.2025.104813

Natural selection has favoured the incorporation of ions, including transition metals, in materials of various 
biological structures susceptible to mechanical fracture to enhance their failure and wear resistance. With 
regards to insects, only a few taxa have been investigated. The objective of this study was to analyse the 
biomechanical properties of the ovipositor in the damselfly Calopteryx splendens (Harris, 1780) (Odonata, 
Zygoptera, Calopterygidae) through nanoindentation and to ascertain the elemental composition gradient within 
the cuticle using energy-dispersive X-ray spectroscopy. This research represents the first report indicating that 
the damselfly ovipositor exhibits a gradient in the mechanical properties of the cuticle, with Young’s modulus 
ranging from approximately 3.0 to 7.0 GPa and hardness from 0.1 to 0.3 GPa. These properties highly correlate 
with the contents of copper and magnesium, both of which increase in the distal direction. The results also 
suggests that the mechanical properties of the cuticle are significantly influenced by the degree of sclerotization 
revealed by confocal laser scanning microscopy. These findings propose that the material properties of the 
ovipositor cuticle in C. splendens may have adapted to enhance piercing capability and to reduce the risk of 
structural failure during insertion of eggs in plant substrates.

© 2025 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/).