Are centipedes heavy metal? Investigation of cuticular components and metals in the centipede forcipule


Simon Züger

MSc Student
Advisors: Andy Sombke, Harald Krenn

Unit for Integrative Zoology, Department of Evolutionary Biology
University of Vienna


Centipedes are known for their fearsome appearance due to their peculiar forcipules that are used in grabbing, restraining, and poisoning their prey. As their active use exposes them to strong mechanical forces, we hypothesise that especially the distal cuticular components are reinforced. It is known from many arthropods that they incorporate heavy metals into the cuticle of piercing or biting structures, thus increasing their hardness and elasticity. In the mouthparts of different insects, metals like zinc, manganese, iron, and calcium are present in the biting edges of mandibles. In spider chelicerae, or the scorpion stinger, zinc and calcium are embedded to withstand wearing off. Centipede forcipules are evolutionary transformed locomotory legs which have venom glands with an opening at the pointed tip. However, not much is known about the metals and other cuticular components that strengthen these structures. To investigate these properties, we used energy-dispersive X-ray (EDX) to examine elemental components in the cuticle of representative species of all five centipede orders (Scutigeromorpha, Craterostigmomorpha, Lithobiomorpha, Scolopendromorpha, and Geophilomorpha). Furthermore, cuticular hardness gradients were analysed using confocal laser-scanning microscopy (cLSM) based on autofluorescence properties. Additionally, we compared the forcipules with the serial homologous locomotory legs, to test whether this reinforcement only occurs in the weaponized forcipules or is a general feature in the distal structures of these appendages. Finally, our results for individual species and higher taxonomic groups are compared to gain a deeper understanding in taxon-specific modifications and environmental interactions.