Wasp Has Its Own Zinc-Tipped Drill Bit
A parasitic fig wasp comes naturally equipped with a zinc-tipped "drill bit," according to new research.
The useful tool-like system, complete with teeth for boring, is used to drill holes in hard, unripe fruit, according to the paper, which is published in the latest issue of the Journal of Experimental Biology.
Namrata Gundiah from the Indian Institute of Science in Bangalore and graduate student Laksminath Kundanati made the surprising discovery while studying the parasitic fig wasp Apocryta westwoodi grandi.
Using scanning electron microscopy to take a high-resolution look at the insects' ovipositors, the researchers discovered that the end of these long, narrow appendages was made out of zinc.
"Zinc mainly increases the hardness, which will affect the wear resistance of the drill bits," explained Gundiah.
Only females have this type of drill-like ovipositor. They use it to drill through unripe fruit to find the larvae of other insects that are already developing within the fruit.
(As an aside, most figs and other fruits contain insects, both dead and alive. Fig wasps help fig trees to bear fruit, though, and the bug matter provides consumers with extra protein!)
Once the female fig wasp drills through the fruit to larvae, she deposits her own eggs there. As they develop, they will parasitize the larvae, giving baby wasps a nutritional boost.
The mother wasp's ovipositor is a remarkable tool since it is flexible yet sturdy. It can bend, flex, and tolerate massive buckling forces.
The scientists measured the hardness of the teeth at the end of this tool and recorded them as being at .5 GPa, which is a high reading.
As Gundiah said, "That is almost as hard as the acrylic cement used for dental implants."
Gundiah is now attempting to design a minute boring tool to duplicate that of the wasp. Such tiny devices could have medical and other useful applications in future.
Photo: a female parasitic fig wasp. Credit: Lakshminath Kundanati.