| Project/Area Number |
13839015
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Institution | Keio University |
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Principal Investigator |
SUZUKI Atsushi Keio University, School of Medicine, Assistant Professor, 医学部, 講師 (90216359)
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| Project Period (FY) |
2001 – 2002
|
| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Tardigrada / water bear / life history / embryology / rearing |
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| Research Abstract |
A strain of carnivorous tardigrade, Milnesium tardigradum, was reared in water on agar plates at 25℃. The monogonont rotifer Lecane inermis was presented as a food source. This rearing system permitted detailed observation of tardigrade behaviour. Daily measurements of body length allowed the growth rate and moulting cycle of this species to be determined. The life history of M. tardigradum raised under these conditions included up to seven periods of moult. The first and second moults occurred at intervals of 4-5 days, and individuals reached reproductive maturity at the 3rd-instar stage; the first period of egg laying accompanied the third moult. The most rapidly developing animal in the study population laid eggs 12 days after hatching. The egg-laying intervals or moulting intervals of adult animals were around 6-10 days. The mean clutch size was 6.9 eggs. All tardigrades in this laboratory population were female and reproduced by parthenogenesis. The duration of the embryonic stage ranged from 5-16 days. The most long-lived female survived for 58 days after hatching, and laid a total of 41 eggs in 5 separate clutches. The entire life cycle of tardigrades reared under these conditions was recorded and photographed. A brief description of the embryonic development of M. tardigradum was also reported
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