Temperature-dependent energetics of Chaoborus populations: hypothesis for anomalous distributions in the great lakes of East Africa
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Chaoborus, the phantom midge (Insecta, Diptera, Chaoboridae), has a widespread distribution, commonly occurring in lakes and ponds all over the world. In the great lakes region of East Africa Chaoborus is present in Lakes Victoria, Albert, Edward, Malawi and George, but absent from Lakes Tanganyika, Kivu and Turkana. Tropical lakes typically have water temperatures in the range of 22–26 °C year round. Lakes Tanganyika and Kivu have only 20% of their bottom sediments oxygenated during full circulation, contrary to 95–100% in all of the other lakes, excluding Lake Malawi (45%) (Hecky & Kling, 1987). Planktivorous fish are present in all lakes (Lehman, 1995). We hypothesized that the absence of Chaoborus larvae from some lakes of East Africa may be the result of interaction among high temperatures, low oxygen levels, and fish predation.
We developed a model to estimate energetic costs for Chaoborus larvae at temperatures greater than 14 °C. We hoped to shed light on the bioenergetics of Chaoborus populations, and the possibility that extant distributions of Chaoborus larvae are the result of energetic constraints.
We found that relative respiratory and growth costs of Chaoborus larvae are highest in the early stages of development. We estimated that non-feeding instar I larvae living in 25 °C water will starve to death in less than one day. It is possible that Chaoborus populations are prevented from establishing in certain areas because high energetic costs condemn young larvae to death by either predation or starvation.
Key wordsChaoborus energetics temperature
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- Berg, K. & P. M. Jonasson, 1965. Oxygen consumption of profundal lake animals at low oxygen content of the water. Hydrobiologia 26: 131–143.Google Scholar
- Downing, J. A. & F. H. Rigler, 1984. A manual for the assessment of secondary productivity in fresh waters. Blackwell Scientific Publications, Boston.Google Scholar
- Giguere, L. A., 1981. Food assimilation efficiency as a function of temperature and meal sizes in larvae of Chaoborus trivittatus (Diptera: Chaoboridae). J. Anim. Ecol. 50: 103–109.Google Scholar
- Gliwicz, Z. M., 1985. Predation or food limitation: an ultimate reason for extinction of planktonic cladoceran species. Arch. Hydrobiol. 21: 419–430.Google Scholar
- Hecky, R. E. & H. J. Kling, 1987. Phytoplankton ecology of the great lakes in the rift valley of Central Africa. Arch. Hyrobiol. Beih. Ergebn. Limnol. 25: 197–228.Google Scholar
- Larow, E., 1970. The effect of oxygen tension on the vertical migration of Chaoborus larvae. Limnol. Oceanogr. 15: 357–362.Google Scholar
- Lehman, J. T., 1995. Pelagic food webs of the East African Great Lakes In T. C. Johnson & E. Odata (eds), Limnology, Climatology, and Paleolimnology of the East African Lakes. Jing, Uganda.Google Scholar
- Lewis, W. M., 1975. Distribution and feeding habits of a tropical Chaoborus population. Verh. Int. Ver. Limnol. 19: 3106–3119.Google Scholar
- MacDonald, W. W., 1956. Observations on the biology and behavior of chaoborids and chironomids in Lake Victoria and on the feeding habits of the ‘elephant-snout’ fish (Morymyrus kannume Forsk). J. Anim. Ecol. 25: 36–53.Google Scholar
- McGowan, L. M., 1974. Ecological studies on Chaoborus (Diptera, Chaoboridae) in Lake George, Uganda. Freshwat. Biol. 4: 483–505.Google Scholar
- Northcote, T. G., C. J. Walters & J. M. B. Hume, 1978. Initial impacts of experimental fish introductions on the macrozooplankton of small oligotrophic lakes. Verh. Int. Ver. Limnol. 20: 2003–2012.Google Scholar
- Peters, R. H., 1983. The ecological impacts of body size. Cambridge University Press, New York.Google Scholar
- Ratte, H. T., 1984. Temperature and Insect Development. In K. H. Hoffman (ed.), Environmental Physiology and Biochemistry of Insects. Springer Verlag, Berlin.Google Scholar
- Stahl, J. B., 1966. The ecology of Chaoborus in Myers Lake, Indiana. Limnol. Oceanogr. 11: 177–183.Google Scholar
- Swift, M. C., 1976. Energetics of vertical migration in Chaoborus trivittatus larvae. Ecology 57: 900–914.Google Scholar
- Thornhill, R. & J. Alcock, 1983. Evolution of Insect Mating Systems. Harvard University Press, Cambridge, Mass.Google Scholar