|D. irritator female Tom Murray|
|Long ovipositor- eeob.iastate.edu|
In a study in 1998, Donald L. J. Quicke and colleagues found that many genera of hymenoptera (sawflies, wasps, bees and ants)) incorporate metal in the cuticle of their ovipositors and jaws which reduces abrasive wear. The ovipositors are adaptations of what we would call "stingers," used to position the egg on an unsuspecting larvae of beetles, lepidoptera (butterflies and moths) and even other hymenoptera. The metal can make up to 10% of the ovipositor's weight. Many of these same species have metal deposition in the adult's jaws. This is necessary to chew its way out of the host plant once it emerges from the pupa. In general, no metal is found in the ovipositors of hymenoptera which penetrate soft materials or don't penetrate in egg laying.
|"Stump stabber"-Adrian D. Thysse|
Hymenoptera are not alone in their use of metal. The teeth of some caterpillars have been shown to be hardened by zinc deposition.* How do you determine metal without tedious drilling after asking the cat to "open wide?" Scanning electron micrograph images detect the presence and distribution of zinc in both the jaws and the tarsi of some forest caterpillars that chew into the hardened lignin of living trees. Details of the 1999 study are at livingwithinsects.
|Zinc deposition in caterpillar mandible *|
*A. R. FONTAINE, N. OLSEN, R. A. RING & C. L. SINGLA. 1991. Cuticular metal hardening of mouthparts and claws of some forest insects of British Columbia. J. ENTOMOL. Soc. BRIT. COLUMBIA 88: 45-55.