[xipho]

And various other wasps have heavy metals concentrated near the apex of their mandibles.

There's also resilin, an elastic-like compound(?) that concentrates energy at certain parts of insect joins, used during jumping, or other fast movements.

[throwanem]

Which wasps?

[xipho]

https://link.springer.com/article/10.1007/s13127-020-00448-x

See references therein for metals numerous other orders of not just insects but arthropods.

"metal mandible Hymenoptera" as a search.