The parasitic fig wasp pierces the tough outer layer of figs with a zinc-toothed ovipositor that is as hard as dental cement.

Scientists have discovered that the parasitic fig wasp uses a zinc-hardened ovipositor to penetrate tough, unripe figs. Understanding the mechanics of the fig wasp ovipositor could lead too the development of biomimetic medical tools such as tissue probes and needle biopsies.

Like many other insects, the parasitic fig wasp (Apocryta westwoodi grandi) lays its eggs in a substrate that protects the developing larvae and provides them with nutrition. However, the unripe figs that the wasp targets are protected by a tough protective layer. Namrata Gundiah from the Indian Institute of Science, Bangalore, was fascinated by how the thin, hollow and flexible ovipositor, used to deliver eggs, was able the penetrate the tough figs.

Using scanning electron microscopy, Gundiah and her PhD student Laksminath Kundanati first compared the ovipositors of parasitic fig wasps with the closely related pollinating fig wasps. They found that unlike the ovipositor of pollinating wasps which were spoon-shaped at the tip, parasitic wasp ovipositors had teeth-like projections. Furthermore, energy dispersive X-ray analysis (EDS) showed that these teeth were enriched with zinc.
“Zinc mainly increases the hardness, which will affect the wear resistance of the drill bits”, explained Gundiah.

The researchers also went on to quantify the hardness of the ovipositors with atomic force microscopy. Their results showed that the zinc-enriched teeth had a hardness of 0.5 GPa, almost as hard as acrylic cement used for dental implants.

Gundiah hopes that their research on parasitic fig wasps will facilitate the design of new medical drills that are both hard and flexible, enabling the delivery of drugs or gene therapy without the need for invasive surgery.

The article can be found at: Kundanati et al. (2014) Biomechanics of Substrate Boring by Fig Wasps.

Copyright: Asian Scientist Magazine; Photo: James Niland/Flickr/CC.

Read More: http://www.asianscientist.com/in-the-lab/parasitic-fig-wasps-equipped-zinc-tipped-drills-2014/