Identification of Nanopillars on the Cuticle of the Aquatic Larvae of the Drone Fly (Diptera: Syrphidae)

Here, we describe a nano-scale surface structure on the rat-tailed maggot, the aquatic larva of the Drone fly Eristalis tenax (L.). Larvae of this syrphid hover fly live in stagnant, anaerobic water-courses that are rich in organic matter. The larvae burrow into fetid slurry and feed on microorganisms which they filter out from the organic material. This environment is rich in bacteria, fungi and algae with the capacity to form biofilms that might develop on the larval surface and harm them. Using transmission and scanning electron microscopy we have identified an array of slender (typically < 100 nm in diameter) nanopillars that cover the surface of the larvae. The high density and dimensions of these spine-like projections appear to make it difficult for bacteria to colonize the surface of the animal. This may interfere with the formation of biofilms and potentially act as a defence against bacterial infection.