Central control of tarsal thresholds for proboscis extension in the blowfly

ABSTRACT. The literature contains contrary reports with respect to the control of the proboscis extension of blowflies in response to stimulatory solutions. Control could be effected centrally, peripherally or by a combination of both. In this report a comparison of (i) behavioural responsiveness to sucrose (measured by tarsal thresholds for proboscis extension) and (ii) sensitivity of tarsal sugar receptors (measured from 0.1 to 1.1 s after stimulus onset) both before and 1 h after feeding of male Protophormia terraenovae suggests that the observed decrease in behavioural responsiveness after feeding is due to central inhibition rather than to a decline in peripheral sensitivity.