, Volume 138, Issue 1, pp 28–31

On the use of spleen mass as a measure of avian immune system strength


DOI: 10.1007/s00442-003-1409-y

Cite this article as:
Smith, K.G. & Hunt, J.L. Oecologia (2004) 138: 28. doi:10.1007/s00442-003-1409-y


The avian spleen has been frequently used in studies of avian ecology, parasitology, and evolution to infer immune system strength in birds. Traditionally, it has been assumed that a large spleen is representative of a strong immune system and conclusions based on this assumption have led to interesting interpretations of the role of disease and parasitism, for example in predator-prey interactions. This assumption of a positive relationship between spleen size and immune system strength has been made despite an incomplete understanding of the physiology of the avian spleen and little evidence of the validity of such an assumption. In this response, we demonstrate that the assumption of a predictable, positive relationship between spleen size and immunocompetence may be unjustified based on what is known of avian splenology. We also review recent research that may indicate that the inverse of the above assumption is true and we discuss general limitations of the use of the spleen as an indicator of immune system strength in birds. Finally, we make recommendations for future research topics in this field of study.


Aves Evolutionary ecology Host-parasite interactions Immunocompetence Immunology 

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  1. 1.Department of Ecology and Evolutionary BiologyThe University of TennesseeKnoxvilleUSA
  2. 2.Department of Biological SciencesAuburn UniversityUSA

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