There's also resilin, an elastic-like compound(?) that concentrates energy at certain parts of insect joins, used during jumping, or other fast movements.
See references therein for metals numerous other orders of not just insects but arthropods.
"metal mandible Hymenoptera" as a search.
There's also resilin, an elastic-like compound(?) that concentrates energy at certain parts of insect joins, used during jumping, or other fast movements.