Meeting Abstract
S1.6 Sunday, Jan. 4 The tale of two mechanosensors: antennal role in insect flight SANE, Sanjay P.; National Center for Biological Sciences sane@ncbs.res.in
Mechanosensors located at the base of insect antennae are crucial in the control of flight trajectories of insects such as moths and butterflies. In these insects, the antennal base consists of two sets of mechanosensors involved in control and sensing of antennal motion. One set, called the Johnstons organs is composed of several scolopidial units which respond to the relative motion between the flagellar-pedicel joint. Another set, the Bohms bristles, consists of bristle fields arranged orthogonally on the surface of scape and pedicel. Although the exact mechanisms of their involvement in flight are still under investigation, it is increasingly evident that these two sets of mechanosensors fulfill functionally distinct roles during flight in the hawk moths. The Bohms bristles are ideally positioned to respond to large angular movements of the antenna and likely mediate the precise positioning of the antennae during flight. In contrast, the individual units of Johnstons organ respond to the higher frequency vibrations of the antennae during flight. Neuroanatomical investigations of the Bohms bristles pathway suggest that the sensory information from the bristle fields arborizes in close proximity to the dendritic fields belonging to the antennal motor neurons. This suggests that there may be a close communication between the input from the Bohms bristles and the antennal muscles to enable a rapid but precise control of the antennal position via a simple negative feedback loop. A constant inter-antennal angle may then enable the Johnstons organs to unambiguously measure the input from the antennal vibrations to provide specific sensory feedback necessary for flight control. Thus, inputs from both mechanosensors are necessary to ensure that antenna can serve as a mechanosensory organ that reports information about self-motion during flight.
