The Mechanism of the Pupal Gin Trap

1. Despite partial degeneration of the larval muscles and reorganization of the nervous system, pupae of the privet hawk moth, Sphinx ligustri , show simple behaviour patterns including abdominal flexion and twirling, and a movement which closes the gin trap. 2. The gin trap closes when the motor neurones driving muscles in the ipsilateral half of the adjacent anterior segment discharge together in a brief high-frequency volley. 3. The system which excites the volley is restricted to these motor neurones and is activated only by input at a high frequency from triggering receptors. 4. A second system excites efferent neurones in several segments and is driven by triggering and non-triggering receptors. Therefore at low input frequencies the discrimination between the two kinds of receptors disappears. 5. Motor patterns associated with twirling movements drive the efferent neurones in a sequence which interferes with their simultaneous response to triggering inputs. 6. The arrangement of the closure system shows that the afferent neurones are separated from the efferent neurones by at least one interneurone.

[1]  J. Pringle,et al.  Proprioception In Insects , 1938 .

[2]  J. Pringle.  Proprioception In Insects: II. The Action Of The Campaniform Sensilla On The Legs , 1938 .

[3]  V. Wigglesworth,et al.  Local and General Factors in the Development of "Pattern" in Rhodnius Prolixus (Hemiptera) , 1940 .

[4]  J. Pringle,et al.  The Response Of A Sense Organ To A Harmonic Stimulus , 1952 .

[5]  V. Wigglesworth.  The Origin of Sensory Neurones in an Insect, Rhodnius prolixus (Hemiptera) , 1953 .

[6]  M. Locke,et al.  THE CUTICULAR PATTERN IN AN INSECT, RHODNIUS PROLIXUS STAL , 1959 .

[7]  C. Rowell.  The Structure and Function of the Prothoracic Spine of the Desert Locust, Schistocerca Gregaria ForskÅl , 1961 .

[8]  N. Suga,et al.  Pharmacological Studies on the Auditory Synapses in a Grasshopper , 1961 .

[9]  P. Lawrence.  Gradients in the Insect Segment: The Orientation of Hairs in the Milkweed Bug Oncopeltus Fasciatus , 1966 .

[10]  R. D. Weevers.  A lepidopteran saline: effects of inorganic cation concentrations on sensory, reflex and motor responses in a herbivorous insect. , 1966, The Journal of experimental biology.

[11]  Weevers Rd.  The physiology of lepidopteran muscle receptor. I. The sensory response to stretching. , 1966 .

[12]  R. D. Weevers.  The physiology of a lepidopteran muscle receptor. II. The function of the receptor muscle. , 1966, The Journal of experimental biology.

[13]  C. Stern.  Genetic Mosaics, And Other Essays , 1968 .

[14]  M. Jacobson,et al.  Neuronal Specification of Cutaneous Nerves through Connections with Skin Grafts in the Frog , 1968, Science.

[15]  J. Boistel.  The Synaptic Transmission and Related Phenomena in Insects , 1968 .

[16]  H. F. Stumpf.  Further Studies on Gradient-Dependent Diversification in the Pupal Cuticle of Galleria Mellonella , 1968 .

[17]  P. Usherwood,et al.  Tarsal Receptors and Leg Reflexes in the Locust and GRASSHOPPER , 1968 .

[18]  J. Camhi,et al.  Locust wind receptors. I. Transducer mechanics and sensory response. , 1969, The Journal of experimental biology.

[19]  T. Nichols,et al.  Electrophysiological demonstration that cockroach tibial tactile spines have separate sensory axons. , 1969, Journal of insect physiology.

[20]  J. Camhi,et al.  Locust wind receptors. II. Interneurones in the cervical connective. , 1969, The Journal of experimental biology.

[21]  M. Jacobson,et al.  Development of neuronal connections with skin grafts in frogs: Behavioral and electrophysiological studies , 1969, The Journal of comparative neurology.

[22]  Peter A. Lawrence,et al.  Polarity and Patterns in the Postembryonic Development of Insects , 1970 .

[23]  Ronald R. Hoy,et al.  Postembryonic Development of Adult Motor Patterns in Crickets: A Neural Analysis , 1970, Science.

[24]  R. M. Gaze.  The formation of nerve connections , 1970 .

[25]  J J Callec,et al.  Further studies on synaptic transmission in insects. II. Relations between sensory information and its synaptic integration at the level of a single giant axon in the cockroach. , 1971, The Journal of experimental biology.

[26]  F. Crick,et al.  A gradient of positional information in an insect, Rhodnius. , 1972, Journal of cell science.

[27]  C. Bate.  The Mechanism of the Pupal Gin Trap: I. Segmental Gradients and the Connexions of the Triggering Sensilla , 1973 .

[28]  The Mechanism of the Pupal Gin Trap: III. Interneurones and the Origin of the Closure Mechanism , 1973 .