Ant-Mediated Seed Dispersal Alters Pattern of Relatedness in a Population of Trillium grandiflorum

Abstract

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Spatial patterns of seed dispersal, their determinants and consequences for recruitment

“…The few studies that report data for multiple periods, whether within or across years, generally do find variation in seed dispersion. For example, ants dispersed Trillium grandiflorum seeds significantly longer distances and deposited them in larger aggregations in one year than in the next 24 . Temporal variation might be evident only in parts of the landscape; for example, seed-dispersion patterns of the wind-dispersed Mediterranean tree Aleppo pine (Pinus halepensis) are interseasonally variable far from, but not near to, seed sources 25 .…”

Spatial Population Genetic Structure in Trillium Grandiflorum: The Roles of Dispersal, Mating, History, and Selection

“…To determine the multilocus genotypes of the plants, we collected 1-cm 2 sections of leaf tissue from R and NR plants and 0.2-cm 2 sections from J plants during [1989][1990][1991][1992][1993] growing seasons for use in starch gel electrophoresis. Extraction and electrophoresis procedures were those of Gottlieb (1981Gottlieb ( , 1984 Kalisz et al (1999) to determine the outcrossing rate in this population.…”

“…We used seed dispersal and mating system data previously published for this T. grandiflorum population (Kalisz et al 1999) to simulate the SPGS of the postdispersal seeds produced by the 328 mapped R plants.…”

“…Using the methods of Ritland and Jain (1981) and Ritland (1989), this study population has been found to be highly outcrossing (multilocus t ϭ 1.05, SE ϭ 0.056) with seeds within fruits being primarily full siblings (r p ϭ 0.82, SE ϭ 0.13) sired on average by N ϭ 1/r p ϭ 1.2 effective males (Kalisz et al 1999). In addition, field experiments conducted to test for self-pollination indicated a complete in- ability of flowers to self-pollinate (Kalisz et al 1999). Thus, the seeds within a fruit are likely the products of outcrossing among plants that do not share incompatibility alleles.…”

“…Kalisz et al (1999) quantified the natural pattern of seed movement by ants away from individual T. grandiflorum maternal plants on our study site during 1991 and 1992. Seeds were uniquely colored coded and labeled using Scandium-46, a gamma-and beta-emitting radionuclide which permitted relocation and identification to sibship.…”