Plastron respiration in the marine fly Canace

Abstract

The larva of the fly Canace nasica Haliday feeds on Enteromorpha in the intertidal zone. Its pupae, like those of a number of other intertidal flies, have plastron-bearing spiracular gills. The gills are unlike those of any other known Diptera in that they are modified spiracles: those of other flies are modifications of the body wall adjoining the spiracle, or of both the body wall and the spiracle. Although the spiracular gills are pupal structures, they are the respiratory organs of the adult before it emerges from the puparium.