“Airborne Organism” Identified

Abstract

IF the authors of the recent report¹ had chanced to include an insect physiologist among those consulted about the unusual objects detected by electron microscopy in an atmospheric aerosol, their quest would have been at an end ! These structures are brochosomes, bizarre excretory products of the Malpighian tubules of leaf hoppers (Homoptera; Jassidae). They were discovered on wing membranes and elsewhere on the surface of these insects by Tulloch, Shapiro and Cochrane² and Wilde and Cochrane³, who named these structures to accord with their net-like form. Subsequently it was found⁴, by examination of thin sections in the electron microscope, that brochosomes are produced intracellularly in the urine-secreting tubules; their eventual distribution over the surface cuticle seems to be achieved by the insect manipulating the excreted pellets with its posterior pair of legs⁵.