Skip to main content

The relationship between size, budding rate, and growth efficiency in three species of hydra


Three species of the fresh water carnivore hydra,H. littoralis, H. pseudoligactis, andC. viridissima present a graduation in size with the first species the largest and albinoChlorohydra the smallest. When presented with a daily overabundance of food (artemia), considerable variation in food intake and gross efficiency of growth (proportion of food energy consumed that is turned into new protoplasm or buds) existed among the species. The degree of association between size of species and food intake was highly significant. However, budding efficiency among the species was found to be independent of food intake (when the effects of species size were eliminated) and of species size (when the effects of food intake were removed). However, species with high (low) efficiencies have significantly higher (lower) reproductive rates.

A lowering of the temperature from 25° to 15° C. increased the size of the species, increased food intake, but decreased reproductive rate. In all species exceptH. pseudoligactis a corresponding increase in the production of bud energy with no change in efficiency also occurred. On the other hand, lowering of the temperature forH. pseudoligactis significantly lowered reproductive efficiency but had no effect on the total calorific output of buds. This species, in constrast to the others, appears to have a compensatory ability to adjust its efficiency to maintain a high calorific output when temperature increases.

It was also found that albinoChlorohydra have budding efficiencies of around 35 percent which are not influenced by changes in food intake or light. Normal green hydras, however, have efficiencies which range from 40 to 62 percent above their albino counterparts when fed once a day and once every two days in light respectively. It it concluded first, that the symbiotic algae in the gastrodermals cells of green hydra contribute quantitatively in the order of the above amounts to the growth process in this species, and second, that green hydras have the ablity to increase their growth efficiency when food intake is reduced thus reducing the drop in calorific but output that normally occurs in the albino (control) form.

This is a preview of subscription content, access via your institution.


  • Brien, P. (1953) La pérennité somatique.,Biol. Rev.,28: 308–349.

    Google Scholar 

  • Bryden, R. R. (1952) Ecology ofPelmatohydra oligactis in Kirkpatricks Lake, Tennessee.Ecol. Monogr.,22: 45–68.

    Article  Google Scholar 

  • Burnett, A. L. (1961) The growth process in hydra.J. Exp. Zool.,146: 21–84.

    Article  Google Scholar 

  • Kabat, E. A. andM. M. Mayer (1961) Experimental Immunochemistry. Springfield.

  • Loomis, W. F. (1953) The cultivation of hydra under controlled conditions.Science,117: 565–566.

    PubMed  CAS  Article  Google Scholar 

  • Loomis, W. F. (1954) Environmental factors controlling growth in hydra.J. Exp. Zool.,126: 223–234.

    Article  Google Scholar 

  • Miller, D. E. (1936) A limnological study ofPelmatohydra with special reference to their quantitative seasonal distribution.Trans. Amer. Micros. Soc. 55: 123–193.

    CAS  Article  Google Scholar 

  • Muscatine, L. (1961) Symbiosis in marine and freshwater coelenterates. In: The biology of hydra and some other coelenterates. Eds.H. M. Lenhoff andW. F. Loomis, 255–264. Coral Gables.

  • Muscatine, L. andH. M. Lenhoff (1963) Symbiosis: On the role of algae symbiotic with hydra.Science,142: 956–958.

    Article  Google Scholar 

  • Richman, S. (1958) The transformation of energy byDaphnia pulex.Ecol. Monogr.,28: 273–291.

    Article  Google Scholar 

  • Slobodkin, L. B. (1962) Energy in animal ecology. In: Advances in Ecological Research, Ed.J. B. Craig. 1: 69–101. New York.

  • Slobodkin, L. B. (1964a) Experimental populations of hydrida.J. Anim. Ecol.,33: 131–148. Supplement.

    Article  Google Scholar 

  • Slobodkin, L. B. (1964b) The strategy of evolution.Amer. Sci.,52: 342–357.

    PubMed  CAS  Google Scholar 

  • Stiven, A. E. (1962) The effect of temperature and feeding on the intrinsic rate of increase of three species of hydra.Ecol.,43: 325–328.

    Article  Google Scholar 

  • Stiven, A. E. (1964) Experimental studies on the host-parasite system hydra andHydramoeba hydroxena (Entz). II. The components of a simple epidemic.Ecol. Monogr.,34: 119–142.

    Article  Google Scholar 

  • Whitney, D. D. (1907) Artifical removal of the green bodies ofHydra viridis.Biol. Bull.,13: 291–299.

    Google Scholar 

Download references

Author information

Authors and Affiliations


Additional information

This study was supported by a National Science Foundation Grant (GB-912)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Stiven, A.E. The relationship between size, budding rate, and growth efficiency in three species of hydra. Res Popul Ecol 7, 1–15 (1965).

Download citation

  • Issue Date:

  • DOI:


  • Food Intake
  • Reproductive Rate
  • Growth Efficiency
  • Food Energy
  • Symbiotic Alga