Cuticular Metals: Quantification and Mapping by Complementary Techniques

Abstract

Metal-replete cuticle was characterised by back-scattered electron imaging, secondary ion mass spectrometry, proton induced X-ray emission and SEM-X-ray microanalysis. Each technique was found to have singular advantages and limitations for localising and quantifying metal content. Manganese and zinc were found coincident at the mandibular cutting edge of the leaf-cutting ant Atta sexdens; these two metals were found in different zones within jaws of the ragworm, Nereis virens; while only manganese was found in the jaws of the termite C. cumulans. Copyright 1997 Academic Press

Biomechanics of substrate boring by fig wasps

“…Pollinator fig wasps have a spoon-like structure in contrast to the sharp and long ovipositors with teeth-like projections at the parasitoid ovipositor tip that are probably adapted for oviposition. Earlier studies examined the ovipositor morphology in various parasitic Hymenoptera and suggested that many morphological features in ovipositor structures are matched to specific host types (Quicke et al, 1999;Rahman et al, 1998;Fawke et al, 1997;Broad and Quicke, 2000;LeRalec et al, 1996). These studies also showed the presence of transition metals, such as zinc, manganese and calcium, in the tips of the ovipositors using X-ray microanalysis.…”

“…The ovipositors of wood-boring wasps show little evidence of wear and tear of their cutting parts . It is hypothesized that the presence of zinc and manganese hardens the insect cuticle and permits it to cut through hard substrates such as wood Hillerton and Vincent, 1982;Fawke et al, 1997). However, the distribution of metals in insect ovipositors and their direct correlation with local material properties has not been explored to date.…”

“…Similarly, the presence of transition metals in larvae mandibles of Stegobium paniceum and Gibbium aequinoctiale species of beetles aids in boring into hard seeds as oppposed to others without metals, which are incapable of seed boring (Morgan et al, 2003). The presence of transition metals in insect cuticle and mandible is hypothesized to increase material hardness to permit cutting through hard substrates with minimal wear (Schofield et al, 2002;Schofield et al, 2003;Lichtenegger, 2003;Quicke et al, 1998;Hillerton and Vincent, 1982;Fawke et al, 1997). Although repeated use of the ovipositor when boring through stiff substrates is expected to cause increased wear in the interacting surfaces, the ovipositors of wood-boring wasps show little evidence of wear and tear of their cutting parts .…”

Heavy Metals in the Jaws of Invertebrates

“…Arthropod jaw tissues may also contain impressive metal levels, in particular Zn or Mn as first shown by Hillerton and Vincent [48]; published metal contents are summarized in Table 1. The leaf-cutter ant is one of the best studied systems [49,50] with mandibles exhibiting a range of serrations at the cutting edge enriched in Zn (Figure 8b) [49]. The Zn content gradually decreases from the cutting edge towards the trailing part ( Figure 8c).…”

“…In arthropod mandibles and ovipositors, Zn and Mn appear to be separate in most cases even in species that contain both elements. One exception is given by the mandibular teeth of the leaf-cutter ant, where secondary ion mass spectrometry (SIMS) data show at least partial co-localization event though the Mn concentration is 20 times smaller than that of Zn [50]. The separate use of Zn [49].…”