Kingdom - Animalia
The body of Ceriodaphnia is surrounded by a hard, spherical shell called a carapace (Balcer et al. 1984). Ceriodaphnia can be differentiated from other cladocerans by the lack of a rostrum and tail spine. Also, Ceriodaphnia have a very noticeable cervical sinus, or an indentation on the dorsal side of the body (Fig. 1). The head is angled ventrally and is mostly composed of a large compound eye (Balcer et al. 1984) (Fig. 2). Both males and females have small first antennae. The males can be recognized from the females by the presence of long, robust setae on their first antennae. They also have modified first thoracic appendages (Balcer et al. 1984). Females have a triangle-shaped dorsal cavity where the egg(s) are stored (Ward and Whipple 1959). The males range in size from 0.4-0.8 mm, whereas the size range of females is 0.4 to 1.4 mm depending on the species (Balcer et al. 1984). The postabdominal claw is often used to differentiate among different Ceriodaphnia species. For example, C. quadrangula has 7-9 anal spines on its postabdominal claw (Pennak 1978)(Fig. 3).
At least one species of the genus Ceriodaphnia is present in every one of the Great Lakes (Balcer et al. 1984). Lake Erie is the only lake of the five Great Lakes that has each of the five Ceriodaphnia species. Ceriodaphnia quadrangula is the most wide spread of all Ceriodaphnia species with ranges in Europe, Asia, and South America (Balcer et al. 1984).
Lauridsen et al. (1999) found that Ceriodaphnia dubia were more abundant in lakes with intermediate abundances of fish. This is because fish predominantly prey upon the bigger, more obvious zooplankton like Daphnia species. Lauridsen et al. (1999) also concluded that Ceriodaphnia are more likely to be found in the littoral zone. This happens primarily because of the lack of larger zooplankton in those areas. Smiley and Tessier (1998) found that Ceriodaphnia preferred limnetic areas in the summer and littoral areas in autumn. It has also been shown that Ceriodaphnia exhibit diel horizontal movement from open waters in the day to littoral waters at night (Smiley and Tessier 1998).
Ceriodaphnia feed by filtering water with their thoracic appendages and eat any phytoplankton that drift by their carapace opening. Ceriodaphnia are one of the most efficient bacteria consumers of all the zooplankton species. Porter et al. (1983) determined that Ceriodaphnia lacustris can filter bacteria at a rate of 0.31 ml anim-1 h-1. Gophen et al. (1974) found that Ceriodaphnia reticulata actually prefer Chlorobium phaeobacteroides over Chlamydomonas. A possible explanation might be that C. reticulata can digest the bacteria easier because of the lack of cell walls.
Temperature is one of the major determinants of the feeding rate of Ceriodaphnia. Gophen (1976) showed that Ceriodaphnia feed at higher rates when the water temperature increases. This happens up to a certain point. According to Gophen (1976), the optimum temperature for C. reticulata was in the range of 20-22 oC.
Growth and Reproduction
Ceriodaphnia reproduces mainly via parthenogenesis. This happens only in the summer months. Ephippium-covered eggs are produced by the female and carried on her back (Fig. 4). She then molts, which releases the eggs, and the eggs temporarily float. Females will produce males if a stimulus, like the occurrence of females bumping into other females. The eggs stay dormant throughout the winter and hatch the following year when the water temperatures are warm enough (Balcer et al. 1984).
Food quantity, pH, and water temperature can all affect the growth and reproduction of Ceriodaphnia. O'Brien and DeNoyelles (1974) found that high cell concentrations of algae reduce filtering rates of C. reticulata, which then reduces growth. Rose et al. (2000) also determined that low concentrations of food decrease both the population growth rate of C. dubia as well as the average number of eggs produced per female. Besides food quantity, pH is another important characteristic that effects reproduction. For example, Belanger and Cherry (1990) showed that Ceriodaphnia living in alkaline environments produce less offspring than those living in more neutral conditions. Finally Gophen (1976) showed that reproduction and growth rate of C. reticulata decreased at temperatures above 22 oC due to the increase in energy requirements from increased respiration rates.
Figure 1. Ceriodaphnia quadrangula with an arrow pointing to the cervical sinus.
Figure 2. A close up on the head of Ceriodaphnia quadrangula. Notice how the head is angled ventrally.
Figure 3. The postabdominal claw of Ceriodaphnia quadrangula showing the presence of 7-9 anal spines.
Figure 4. A femele Ceriodaphnia quadrangula with two eggs in her brood pouch next to a younger C. quadrangula.
Balcer, M. D., N. L. Korda, and S. I. Dodson. 1984. Zooplankton of the Great Lakes: A Guide to the Identification and Ecology of the Common Crustacean Species. University of Wisconsin Pres. Madison, Wisconsin. pg. 58-60.
Belanger, S. E. and D. S. Cherry. 1990. Interacting Effects of pH Acclimation, pH, and Heavy Metals on Acute and Chronic Toxicity to Ceriodaphnia dubia (Cladocera). J. Crust. Bio. 10: 225-235.
Gophen, M. 1976. Temperature Dependance of Food Intake, Ammonia Excretion and Respiration in Ceriodaphnia reticulata (Jurine)(Lake Kinneret, Isreal). Freshwater Biology 6(5): 451-455.
Gophen, M., B. Z. Cavari, and T. Berman. 1974. Zooplankton Feeding on Differentially Labeled Algae and Bacteria. Nature 247: 391-392.
Lauridsen, T. L., E. Jeppesen, S. F. Mitchell, D. M. Lodge, and R. L. Burks. 1999. Diel Variation in Horizontal Distribution of Daphnia and Ceriodaphnia in Oligotrophic and Mesotrophic Lakes with Contrasting Fish Densities. Hydrobiologia 408/409(0): 241-250.
O'Brien, W. J. and F. DeNoyelles, Jr. 1974. Filtering Rate of Ceriodaphnia reticulata in Pond Waters of Varying Phytoplankton Concentrations. American Midland Naturalist 91(2): 509-512.
Pennak, R. W. 1978. Fresh-Water Invertebrates of the United States Second Edition. John Wiley and Sons, New York. Pg. 371.
Porter, K. G., Y. S. Feig, and E. F. Vetter. 1983. Morphology, Flow Regimes, and Filtering Rates of Daphnia, Ceriodaphnia, and Bosmina Fed Natural Bacteria. Oecologia. 58(2): 56-163.
Rose, R. M., M. St. J. Warne, and R. P. Lim. 2000. Life History Responses of the Cladoceran Ceriodaphnia cf. dubia to Variation in Food Concentration. Hydrobiologia 427(1): 59-64.
Smiley, E. A. and A. J. Tessier. 1998. Environmental Gradients and the Horizontal Distribution of Microcrustaceans in Lakes. Freshwater Biology 39(3): 397-409.
Ward, H. B. and G. C. Whipple. 1959. Freshwater Biology, Second Edition. pg. 617. Wiley and Sons, Inc. New York.