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Dispersal of mimetic seeds of three species of Ormosia (Leguminosae)

Journal of Tropical Ecology

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Abstract

Seeds with 'imitation arils' appear wholly or partially covered by pulp or aril but actually carry no fleshy material. The mimetic seed hypothesis to explain this phenomenon proposes a parasitic relationship in which birds are deceived into dispersing seeds that resemble bird-dispersed fruits, without receiving a nutrient reward. The hard-seed for grit hypothesis proposes a mutualistic relationship in which large, terrestrial birds swallow the exceptionally hard 'mimetic' seeds as grit for grinding the softer seeds on which they feed. They defecate, dispersing the seeds, and abrade the seed surface, enhancing germination. Any fruit mimicry is incidental. Fruiting trees of Ormosia spp. (Leguminosae: Papilionoideae) were observed to ascertain mechanisms of seed dispersal and the role of seemingly mimetic characteristics of the seeds in that dispersal. Seed predation and seed germination were also examined. Ormosia isthamensis and O. macrocalyx (but not O. bopiensis) deceived arboreally-foraging frugivorous birds into taking their mimetic seeds, although rates of seed dispersal were low. These results are consistent with the mimetic seed hypothesis. On the other hand, the rates of disappearance of seeds from the ground under the Ormosia trees, hardness of the seeds, and enhancement of germination with the abrasion of the seed coat are all consistent with the hard-seed for grit hypothesis.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Dispersal of mimetic seeds of three species of Ormosia (Leguminosae)
Series title:
Journal of Tropical Ecology
Volume
14
Issue:
4
Year Published:
1998
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
389-412
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Tropical Ecology
First page:
389
Last page:
412
Number of Pages:
24