D. pulex is characteristically associated with small ponds, although less pigmented populations of D. pulex
may occur in deep, clear lakes, such as Lake
Titicaca (Haney, pers comm.).
has a broad range of habitats. It is the most common Daphnia
found in ephemeral pools, but it also occurs in lakes ranging from ultra
oligotrophic (clear bodied with little pigmentation) to eutrophic, where they may be bright red because of high hemoglobin production. Forms of D. pulex
in large lakes may be
difficult to distinguish from D. pulicaria
has been widely used in zooplankton feeding studies. Results indicate great variability between populations from different lakes, such as their ability to
resist cyanobacteria toxins (3).
The presence of Microcystis aeruginosa
induced ephippia production in D. pulex
in the laboratory (3). Immature stages of copepods may enter the
brood pouch of various Daphnia
species, including D. pulex
, where they consume the daphnid eggs (3)(4)(5). Clones of D. pulex
with a longer secondary abdominal
process are better protected from brood pouch predation by adult Eucyclops agilis
, thus protecting their eggs (6). D. pulex
consistently suppressed populations of
Brachionus calyciflorusKeratella cochlearis
in competition experiments in the lab. This was due to the superior feeding efficiency of Daphnia
also can have direct ”interference competition” effects on K. cochlearis
by drawing the rotifer into the filtering chamber in the feeding currents and then rejecting
the damaged rotifers (7). Interestingly, the more agile rotifer Polyarthra
, can detect these filtering currents and escape by quick lateral swimming motion (7).1) SCHWARTZ
, S. S., D. J. INNES
. 1985. Morphological separation of Daphnia pulex
and Daphnia obtusa
in North America. Limnol.
(2) DODSON, S. I. 1984. Predation of Heterocope septentrionalis on two species of Daphnia: Morphological
defenses and their cost. Ecology. 65: 1249-1257.
(3) GLIWICZ, Z. M. 1994. Retarded growth of cladoceran zooplankton in the presence of copepod predation. Oecologia.
(4) GLIWICZ, Z. M. AND H. STIBOR. 1993. Egg predation by copepods in Daphnia brood cavities. Oecologia. 95: 295-298.
(5) GLIWICZ, Z. M., AND W. LAMPERT. 1994. Clutch-size variability in Daphnia: Body-size related effects of egg predation by cyclopoid copepods. Limnol. Oceanogr.
(6) LAURÉN-MÄÄTTÄ, C., J. HIETALA, AND M. WALLSS. 1997. Responses of
Daphnia pulex populations to toxic cyanobacteria. Freshwater Biol. 37: 635-647.
(7) HEBERT, P. D. N., R. D. WARD, AND L. J. WEIDER. 1988. Clonal-diversity patterns and breeding-system variation in Daphnia
pulex, asexual-sexual complex. Evolution. 42:147-159.
(8) HALL, D. J., AND G. G. WATERMAN. 1967. Zooplankton of the Finger Lakes. Limnol. Oceanogr. 12: 542-544.
(9) Hebert, P.D.N., The Daphnia of North America - an illustrated fauna, CD-ROM, Sept., 1995.
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