Response of the Aphid Myzus persicae (Sulz.) to Some Fluids Applied to the Mouthparts

Many insects ingest food through needlelike mouthparts adapted for piercing. The piercing organ itself usuallv consists of four or more chitinous stylets and is thought to be nonliving. It was therefore unexpected to find that amputating the end of a single stylet had two marked effects on aphids; it prevented feeding, and adults produced far more young than usual while starving (Bradley, 1960). Later I found that these effects can also be caused by inserting the intact stylet tips briefly into various solutions such as nitric acid, formalin, or procaine. An account of this work and of that which followed on how solutions initiated these effects is the scope of this paper.