Biological studies upon Enchytraeus variatus Bouguenec & Giani 1987 in breeding cultures |
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Authors: | V Bouguenec N Giani |
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Institution: | (1) Laboratoire d'Hydrobiologie, U.A. 695 du C.N.R.S., Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex, France |
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Abstract: | The life history of an enchytraeid worm, Enchytraeus variatus, was studied under laboratory conditions at 18–22 °C. This species can reproduce simultaneously by asexual (architomy) or sexual reproduction. The number of ova per cocoon varies from 5 to 20 (x = 10.9). The generation period (from cocoon to next cocoon) varies from 14 to 39 days (x = 26.1) according to the period of the year. The number of generations per year is between 7.3 and 26.1 (x = 14). A mature worm can lay between 23.7 and 25.8 cocoons during its life (254 days as maximum observed) at a mean rate of 0.12 cocoon worm–1 day–1. Experimental cultures were carried out to determine the structure, density and biomass of the populations. A maximal density of 1 396 314 worms was recorded after 85 days of culture. Net production reached 21.48 g m–2 day–1 after 26 days in a culture initiated from cocoons. |
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Keywords: | Oligochaeta Enchytraeidae breeding biology life-cycle production |
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