| Co-Investigator(Kenkyū-buntansha) |
YASUYAMA Kohji Kawasaki Medical School, Dept. of Biology, Research Associate, 助手
OKADA Yoshinori Okayama Univ., Fac. of Science Research Associate, 理学部, 教務員 (10093676)
NIIDA Akiyoshi Okayama Univ., Fac. of Science Lecturer, 理学部, 講師 (80033413)
SAKAI Masaki Okayama Univ., Fac. of Science Associate Professor, 理学部, 助教授 (30027502)
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| Research Abstract |
The present experiments were designed to study mainly the selective degeneration of flight muscles during adult life and sexual dimorphism of flight muscles and nervous system in the cricket (Gryllus bimaculatus DeGeer). The results obtained were as follows : (1) The metathoracic indirect flight muscle (M112a) grew significantly during the first 3 days after the imaginal moult ; soon after muscle mass reached its maximum value, it began to degenerate. The degree of growth and degeneration of M112a in the female was greater than in the male. The degeneration of M112a occurred first in the ventral part of the muscle, and then in the dorsal part. The severance of the motoneurons innervating M112a resulted in the simultaneous degeneration of M112a in both parts. (2) When the young adult was decapitated within 24 hours after the imaginal moult, there was little or no degeneration of M112a visible. The selective degeneration of M112a, however, was visible in the decapitated young adult, into
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which JH hormone was injected daily, as well as in the normal young adults. (3) When the motoneurons innervating M112a were severed immediately after the imaginal moult, the growth of M112a was suppressed, but the timing of degeneration of the denervated M112a was similar to that of the normally innervated M112a. (4) It was evident that there was the sexual dimorphism in the mechanical activity of the direct flight muscle, M90, but the motoneurons innervating M90 did not show significant sexual dimorphism in their morphological characteristics. (5) The tracer experiment using ionic lanthanum clearly demonstrated the presence of transverse ionic passages through the cuticular ductules from the haemocoel to the lumen of the spermathecal duct and glandular cavities. (6) Behavioral experiment showed that the development of mating behavior in the male cricket is a process of enhancement of basic motor patters but not a process of addition of new movements by changes in pattern generation circuits in the central nervous system. Less
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