Physiological effects of diet mixing on consumer fitness: a meta-analysis.

TitlePhysiological effects of diet mixing on consumer fitness: a meta-analysis.
Publication TypeJournal Article
Year of Publication2013
AuthorsLefcheck JS, Whalen MA, Davenport TM, Stone JP, Duffy EJ
JournalEcology
Volume94
Issue3
Pagination565-72
Date Published2013 Mar
Abstract

The degree of dietary generalism among consumers has important consequences for population, community, and ecosystem processes, yet the effects on consumer fitness of mixing food types have not been examined comprehensively. We conducted a meta-analysis of 161 peer-reviewed studies reporting 493 experimental manipulations of prey diversity to test whether diet mixing enhances consumer fitness based on the intrinsic nutritional quality of foods and consumer physiology. Averaged across studies, mixed diets conferred significantly higher fitness than the average of single-species diets, but not the best single prey species. More than half of individual experiments, however, showed maximal growth and reproduction on mixed diets, consistent with the predicted benefits of a balanced diet. Mixed diets including chemically defended prey were no better than the average prey type, opposing the prediction that a diverse diet dilutes toxins. Finally, mixed-model analysis showed that the effect of diet mixing was stronger for herbivores than for higher trophic levels. The generally weak evidence for the nutritional benefits of diet mixing in these primarily laboratory experiments suggests that diet generalism is not strongly favored by the inherent physiological benefits of mixing food types, but is more likely driven by ecological and environmental influences on consumer foraging.

DOI10.1155/2013/979702
Alternate JournalEcology