aristal sensillum [FBbt_00004185]

aristal sensillum

ID: FBbt_00004185

Sensillum of the arista. There are three of these per arista, each consisting of a pair of sensory neurons surrounded by 2 sheath cells. They project into the lymph space of the arista core, where they float freely - unattached to the epidermis. These projections consist of specialized dendrites surrounded throughout their length by sheath cells and distally by an electron dense dendritic sheath. The three projections terminate at different points along the shaft.

Foelix et al., 1989, suggest that the morphology of the highly lamellated neurons found in these sensilla is consistent with a thermosensory function based on the similarity of this morphology to that of thermosensory neurons in the antennae of other insects. However, Sayeed and Benzer, 1996, show that surgical removal of the arista has no effect on the temperature preference of flies, but it does eliminate the preference of flies for dry vs moist air, suggesting a hygrosensory function.