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Observations on the Natural History and Behavior of Erpobdella punctata (Leidy) (Annelida: Hirudinea)
Roy T. Sawyer
The American Midland Naturalist
Vol. 83, No. 1 (Jan., 1970), pp. 65-80
Published by: The University of Notre Dame
Stable URL: http://www.jstor.org/stable/2424006
Page Count: 16
You can always find the topics here!Topics: Cocoons, Eggs, Natural history, Streams, Mortality, Water temperature, Natural springs, Immatures, Earthworms, Ponds
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The life history, fecundity, behavior and feeding habits of the North American leech, Erpobdella punctata, are investigated. There is evidence of an upstream migration in early spring. The size distribution within populations indicates that growth to maturity took one year in a permanent pond, but two years in a stream, perhaps because the stream dried up in summer. It seemed that few survived to a second breeding season. Mortality in the stream was estimated at about 93%, 73% and 93% in the first, second and third years, respectively. Intraspecific and snail predations of cocoons were important causes of mortality. These leeches are scavengers and predators, rather than parasites. Courtship involved mutual stimulation and cocoons were laid primarily in May, correlating with a large increase in water temperature. Each individual laid approximately 10 cocoons, each with five eggs which hatch about 3-4 weeks after being laid.
The American Midland Naturalist © 1970 The University of Notre Dame