Predation on Daphnia pulex by Lepidurus arcticus
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Predation on Daphnia pulex by Lepidurus arcticus. / Christoffersen, Kirsten Seestern.
In: Hydrobiologia, Vol. 442, No. 1-3, 2001, p. 223-229.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Predation on Daphnia pulex by Lepidurus arcticus
AU - Christoffersen, Kirsten Seestern
PY - 2001
Y1 - 2001
N2 - Abstract The tadpole shrimp Lepidurus arcticus frequently occurs in Greenland ponds and shallow lakes with a soft bottom. Literature describes it as mainly a scavenger, feeding on the sediment. Previous observations of its behaviour suggest, however, that large specimens can catch Daphnia pulex when swimming in the water. Experiments were set up to test how efficiently Lepidurus hunts Daphnia and if a functional response between predator and prey exists. It was also tested if temperature and Lepidurus size played a significant role for the predation rate. Lepidurus and Daphnia were sampled from ponds at Zackenberg in northeast Greenland (74° N, 21° E) in August 1998 and were placed in small containers (0.5 l) at desired temperatures. Lepidurus was capable of consuming 5–15 Daphnia per hour at ambient temperatures (5–20 °C) and changes in the temperature had apparently no significant effects on the predation rates. There was, however, a clear difference in feeding activity between size groups, the rates of larger Lepidurus (> 12.5 mm) being two to three times greater than that of smaller specimens (8–10 mm). For both size classes, the predation rates rose with increasing prey concentrations and the saturation levels were far above natural prey densities. Small-sized Daphnia (1.6 mm) were removed at significant faster rates (t-test, p<0.05) than="" larger="" ones="" (2.4="" mm)="" by="">Lepidurus when offered in combination but not when offered separately. Although the recorded predation rates were biased due to the manipulated conditions (e.g. increased encounter rates), Lepidurus appears to be an active and efficient predator on planktonic prey, and its presence in arctic lakes and ponds may consequently have a significant impact on the structure of the planktonic food web. The calculated energetic advantages of plankton as supplement to a benthic diet seemed low (5% of body weight per day).
AB - Abstract The tadpole shrimp Lepidurus arcticus frequently occurs in Greenland ponds and shallow lakes with a soft bottom. Literature describes it as mainly a scavenger, feeding on the sediment. Previous observations of its behaviour suggest, however, that large specimens can catch Daphnia pulex when swimming in the water. Experiments were set up to test how efficiently Lepidurus hunts Daphnia and if a functional response between predator and prey exists. It was also tested if temperature and Lepidurus size played a significant role for the predation rate. Lepidurus and Daphnia were sampled from ponds at Zackenberg in northeast Greenland (74° N, 21° E) in August 1998 and were placed in small containers (0.5 l) at desired temperatures. Lepidurus was capable of consuming 5–15 Daphnia per hour at ambient temperatures (5–20 °C) and changes in the temperature had apparently no significant effects on the predation rates. There was, however, a clear difference in feeding activity between size groups, the rates of larger Lepidurus (> 12.5 mm) being two to three times greater than that of smaller specimens (8–10 mm). For both size classes, the predation rates rose with increasing prey concentrations and the saturation levels were far above natural prey densities. Small-sized Daphnia (1.6 mm) were removed at significant faster rates (t-test, p<0.05) than="" larger="" ones="" (2.4="" mm)="" by="">Lepidurus when offered in combination but not when offered separately. Although the recorded predation rates were biased due to the manipulated conditions (e.g. increased encounter rates), Lepidurus appears to be an active and efficient predator on planktonic prey, and its presence in arctic lakes and ponds may consequently have a significant impact on the structure of the planktonic food web. The calculated energetic advantages of plankton as supplement to a benthic diet seemed low (5% of body weight per day).
KW - Faculty of Science
KW - Lepidurus arcticus - Daphnia pulex - predation - selective feeding
U2 - 10.1023/A:1017584928657
DO - 10.1023/A:1017584928657
M3 - Journal article
VL - 442
SP - 223
EP - 229
JO - Journal of Aquatic Ecosystem Health
JF - Journal of Aquatic Ecosystem Health
SN - 0018-8158
IS - 1-3
ER -
ID: 32912013