Evolutionary implications of fruit-processing limitations in cedar waxwings

D. J. Levey, A. Grajal

Research output: Contribution to journalArticlepeer-review

97 Scopus citations


Bombycilla cedrorum fed two types of artificial fruits with equal seed loads but with different seed sizes consumed significantly more of the larger-seeded fruits. Because large seeds were defecated more quickly than small seeds, the increase in fruit consumption indicated that waxwings are process rate limited. Waxwings separated pulp from seeds and defecated seeds well in advance of pulp, thereby allowing both an increase in consumption and, presumably, a greater assimilation of nutrients in the pulp. Rapid seed processing has influenced pulp composition and seed-packaging traits. In particular, the link between rapid passage of small seeds and pulp through the intestine may help explain why fleshy fruits are high in simple sugars and free amino acids. The size and number of seeds in a fruit may in part be determined by a trade-off between the number of seeds ingested and how far they are dispersed. -from Authors

Original languageEnglish (US)
Pages (from-to)171-189
Number of pages19
JournalAmerican Naturalist
Issue number1
StatePublished - 1991

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics


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