1. Department of Biological Sciences, University of Iowa, 312 Chemistry Building, Iowa City, Iowa 52242, USA
2. Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Ancon, Republic of Panama
3. Departments of Botany and Genetics, University of Georgia, Athens, Georgia 30602, USA

Correspondence to: John D. Nason¹ Correspondence and requests for materials should be addressed to J.D.N. (e-mail: Email: john-nason@uiowa.edu).

Abstract

Despite the recognized importance of maintaining viable populations of keystone plant resources in tropical wildlife parks and forested preserves, the critical question of what constitutes effective breeding units of these species has not been directly addressed. Here we use paternity analysis techniques to reconstruct the genotypes of pollen donor trees and to estimate pollen dispersal distances and breeding population size parameters for Panamanian populations of seven species of monoecious strangler figs (Ficus, Moraceae), a particularly widespread and influential group of keystone producers^{1, 2, 3}. Despite the minute size (1–2 mm) and short lifespan (2–3 d) of the species-specific wasp pollinators (Agaonidae, Chalcidoidea), pollen dispersal was estimated to occur routinely over distances of 5.8–14.2 km between widely spaced host trees. As a result of such extensive pollen movement, breeding units of figs comprise hundreds of intermating individuals distributed over areas of 106–632 km², an order of magnitude larger than has been documented for any other plant species. Moreover, these results should be generalizable to the 350 or so monoecious fig species that share this pollination system⁴. The large areal extent of breeding units of these keystone plant resources has important implications for our understanding of both the evolution of tropical biodiversity and its maintenance by applied conservation efforts.