The Specific Location of Zinc in Insect Mandibles

Abstract

The cutting edges of the mandibles in the locust have been shown to be twice as hard as the rest of the mandible (Hillerton, Reynolds & Vincent, 1982) and this was related to the cutting action employed by the insect. We have investigated the elemental composition of the mandibles of insects from several taxa to see if the hardness is due to ‘mineralization’ as in the ‘teeth’ of several other invertebrates e.g. the radular teeth of Patella, which contain iron and silica (Runham et al. 1969). For the first time we report the specific location, in the cutting edges (incisors) of insect mandibles, of large quantities of two transition elements, zinc and manganese. Metals have been found previously in only a few types of insect cuticle-in exceptional dipteran puparia and some phasmid eggs (Neville, 1975)-but their presence has not been related to any of the mechanical properties of the cuticle.