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Reproductive phenology in Dendrocoelum lacteum (Turbellaria) in South Sweden
Author(s) -
HERRMANN JAN
Publication year - 1985
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1985.tb00186.x
Subject(s) - hatchling , phenology , reproduction , biology , turbellaria , ecology , spring (device) , zoology , hatching , mechanical engineering , engineering
SUMMARY.1 L 266 degree‐days, above a threshold of 1.0°C, were required for cocoons from the triclad Dendrocoelum lacteum to hatch. The relation is described by ln D =6.12–1.17 1nr (D =number of days, T = temperature). 2 Laboratory and field cocoon deposition reached a maximum in late April; peaks of hatchling occurrence were 2 weeks later. The number of hatchlings per cocoon and eocoon viability declined as spring proceeded. Cocoon deposition ceased in June, coincident with regression of the reproductive organs of the adults. 3 Newly hatched triclads in the field are thought to avoid stones for their first weeks. 4 It is suggested that the earlier and more abundant offspring production in South Sweden than in Britain could be attributed to differences in spring temperature conditions.