1997 Fiscal Year Final Research Report Summary
Studies on regulatory mechanism of spinning bahavior in the silkworms.
| Project/Area Number |
07456034
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
蚕糸・昆虫利用学
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| Research Institution | Shinshu University |
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Principal Investigator |
KIGUCHI Kenji Shinshu University, Faculty of Textile Science and Technology, Professor, 信州大学繊維学部, 教授 (50262697)
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| Co-Investigator(Kenkyū-buntansha) |
KANEKATSU Rensuke Shinshu University, Faculty of Textile Science and Technology, Associate Profess, 信州大学繊維学部, 助教授 (60092871)
MIURA Mikihiko Shinshu University, Faculty of Textile Science and Technology, Professor, 信州大学繊維学部, 教授 (60135168)
KOBAYASHI Masaru Shinshu University, Faculty of Textile Science and Technology, Associate Profess (10021164)
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| Project Period (FY) |
1995 – 1997
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| Keywords | silkworm / Bombys mori / Antheraea yamamai / Agrius convolvuli / spinning behavior / cocoon shape / 3D-computer graphics / molting hormorne |
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| Research Abstract |
To clarify regulation mechanism of spinning and cocoon formaiton behavior, behavioral characteristics of the silkworms (Bombyx mori and Antheraea yamamai) were analized by 3D-computer graphics. 'Relationships between hemolymph molting hormone level and spinning behavior were also investigated.
1. Spinning process was recorded by two video cameras. Based on the three dimentional data, serial changes of larval body shape, spinning area, spinning speed and frequency of streching behavior were analized. The results obtained were as follows ; (1) the size of spinning region reduces quickly during the constraction of base and frame for cocooning, and then slowly converge it to the final cocoon size, (2) serial shape changes of larval body can be represented by an appropriate bivariate autoregressive model, (3) streching behavior is one of responsible factors for the appearance of constricted parts in the center of a peanut-shape cocoon.
2. Cocoon shape can be changed experimentally by the mech
… More
anical inhibition of segmental movement by attaching a piece of medical tape ; a larva taped on the 5th larval segment made a round cocoon, while the one taped on the posterior segment (7-10th segment) spun a longer cocoon. The 3DCG analysis showed that the taping treatment affects the bending angle and the fixation of the posterior half of the body. It was also found that spinning speed shows down significantly after the taping treatment. Moreover, taping treatment prolonged spinning period, and consequently delayd pupation. The hemolymph ecdysteroid level was significantly lower than the control, suggesting that the taping affects secretory activity in the brain-corpora allata-prothoracic gland axis.
3. The sweet potato hornworm, Agrius convolvuli, make a pupal room in the soil at the end of the last instar. Characteristics of the behavior was also studied by using an infrared camera-Video recorder system, and a developmental time-table was established for the last larval instar to compare with the spinning behavior of the silkworms. Less
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