Developmental changes in mechanosensory circuits during metamorphosis of the hawkmoth
Linn, David Martin, Jr
Sass, Ronald L.
Master of Science
In the hawkmoth, Manduca sexta, many behaviors are partially or fully functional but are actively suppressed prior to normal expression. The pupal gin-trap reflex is such a behavior and its development prior to repression was examined both behaviorally and physiologically. Behavioral responses similar to the pupae were observed in the latter stages of wandering. These responses were rapid lateral flexions and rotary abdomenal movements. The responses differed from the pupal responses in that the flexions were not segment-specific and the rotary movements were not confined to the abdomen as in the pupa. Physiological responses similar in amplitude to the pupa were also observed in the motorneurons during this stage. The responses also resembled the pupal by way of rapid depolarizations followed by inhibition. The responses differed by being non-segment-specific and repetitive in nature during a stimulation period. The results suggest the reflex is at least partially functional prior to pupation.