Elsevier

Animal Behaviour

Volume 55, Issue 5, May 1998, Pages 1255-1261
Animal Behaviour

Regular Article
Pathogen transmission as a selective force against cannibalism

https://doi.org/10.1006/anbe.1997.9996Get rights and content

Abstract

Cannibalism is uncommon in most species despite being taxonomically widespread. This rarity is surprising, because cannibalism can confer important nutritional and competitive advantages to the cannibal. A general, but untested, explanation for why cannibalism is rare is that cannibals may be especially likely to acquire pathogens from conspecifics, owing to greater genetic similarity among conspecifics and selection for host specificity and resistance to host immune defences among pathogens. We tested this hypothesis by contrasting the fitness consequences of intra- versus interspecific predation of diseased and non-diseased prey. We fed cannibalistic tiger salamander (Ambystoma tigrinum) larvae diseased conspecifics, healthy conspecifics, diseased heterospecifics (a sympatric congener, small-mouthed salamanders,A. texanum), or healthy heterospecifics. Cannibals that ate diseased conspecifics were significantly less likely to survive to metamorphosis and grew significantly less than those that ate diseased heterospecifics, but none of the other groups differed. Tiger salamander larvae also preferentially preyed on heterospecifics when given a choice between healthy conspecifics and heterospecifics. These results suggest that pathogen transmission is an important cost of cannibalism and provide a general explanation for why cannibalism is infrequent in most species.

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f1

Correspondence: D. W. Pfennig, Department of Biology, Coker Hall, CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, U.S.A. (email:[email protected].

f2

S. G. Ho is at the Center for Biotechnology, Northwestern University, 1801 Maple Avenue, Evanston, IL 60201, U.S.A.

f3

E. A. Hoffman is at the Department of Zoology, Oregon State University, Cordley Hall, Corvallis, OR 97331-2914, U.S.A.

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