Ultrastructure of the funicular sensilla of the cabbage root fly,Delia radicum L. (Diptera : Anthomyiidae)

A transmission electron microscope study of the funicular sensilla of the cabbage root fly, Delia radicum, (Diptera : Anthomyiidae), showed 4 types of surface sensilla and 5 types of pit sensilla. The ultrastructure of the surface sensilla indicated all had a primary olfactory function. These include thick-walled multiporous trichoid sensilla, thin-walled multiporous basiconic sensilla (with 2 subtypes), thin-walled multiporous clavate sensilla, and grooved sensilla with channels at the base of each of the grooves. Clavate sensilla had 2 types of dendrites, one tubular, the other “scrolled”. This 2nd type may indicate an additional thermosensitive function. The dorsal pits contained thin-walled multiporous basiconic sensilla with a tapered tip. The ventral pits contain 3 types of sensilla, which have no wall pores and an inflexible socket. These may contain thermo- and/or hygroreceptors and include smooth-walled conical-, smooth-walled tapered- and striated pit sensilla. The 4th type is a grooved pit sensillum similar to the surface type.