Evolution of self‐fertilization at geographical range margins? A comparison of demographic, floral, and mating system variables in central vs. peripheral populations ofAquilegia canadensis(Ranunculaceae)

Abstract

Biogeographic models predict that geographically peripheral populations should be smaller, more sparsely distributed, and have a lower per-capita reproductive rate than populations near the center of a species' range. Plants in peripheral populations may, therefore, receive less pollinator visitation and outcross pollination, which may select for self-fertilization to provide reproductive assurance. We tested these predictions by comparing population size, plant density, seed production, floral traits, and mating system parameters between 10 populations of Aquilegia canadensis near the northern margin of the range with 10 near the range center. Contrary to predictions, peripheral populations were not smaller, less dense, nor less productive than central populations. Nevertheless, we detected substantial regional differences in key floral traits. Plants in central populations produced larger flowers with 68% greater herkogamy and had 30% more flowers open simultaneously than plants in northern populations. However, there was no regional difference in the mating system. In northern populations, 73% (range = 60-88%) of seeds were self-fertilized compared to 76% (51-100%) in central populations. In both regions, adult inbreeding coefficients were near zero, indicating very strong inbreeding depression despite high selfing. Marked geographic variation in key floral traits does not reflect evolutionary differentiation in the mating system.

Variasi Karakter Pembungaan Antar Varian dan Ras Lahan Cendana Sepanjang Gradien Geografis di Gunung Sewu

“…Komponen pembungaan terdiri dari fenologi, struktur, dan display perbungaan (Owens et al 1991). Struktur dan display perbungaan mempengaruhi keberhasilan penyerbukan (Herlihy & Eckert 2005;Arroyo et al 2006) dan reproduksi (Wolf et al 2001;Collin & Shykoff 2003;Weber & Kolb 2013;Agullo et al 2015). Fenologi pembungaan, yang meliputi inisiasi, frekuensi, dan durasi pembungaan (Owens et al 1991), merupakan mekanisme alami untuk beradaptasi secara ekologis maupun fisiologis terhadap kondisi lingkungan (Barrett et al 2006;Richardson et al 2013).…”

“…Fenologi pembungaan, yang meliputi inisiasi, frekuensi, dan durasi pembungaan (Owens et al 1991), merupakan mekanisme alami untuk beradaptasi secara ekologis maupun fisiologis terhadap kondisi lingkungan (Barrett et al 2006;Richardson et al 2013). Variasi fenologi pembungaan berkontribusi pada struktur populasi (Tsaliki & Diekmann 2011;Richardson et al 2013), perilaku agen penyerbuk (Herlihy & Eckert 2005;Arroyo et al 2006), aliran gen (Alizoti et al 2010;Yang et al 2013;Park et al 2014), serta karakter reproduksi (Collin & Shykoff 2003;Alizoti et al 2010;Weber & Kolb 2013;Agullo et al 2015).…”

“…Perbedaan struktur populasi (Byrne et al 2003;Bottin et al 2007;Dani et al 2011) dan struktur reproduksi (Rughkla et al 2006;Warburton et al 2000;Rao et al 2007;Herlihy & Eckert 2005;Barrett et al 2006;Tamla et al 2012) dapat berakibat pada berbedanya sistem perkawinan dan proses reproduksi. Hal serupa terjadi pada Santalum album di India (Rughkla et al 2006), S.…”

The effects of population size on genetic parameters and mating system of sandalwood in Gunung Sewu, Indonesia

“…Genetic markers were widely used and, among these, some have conducted by allozyme markers. Many studies reported strong influences of geographical variation on population structures, and its effects on mating systems (Herlihy and Eckert, 2005;Arroyo et al, 2006) and genetic diversity (Rao et al, 2007;Bottin et al, 2007;Dani et al, 2011;Indrioko and Ratnaningrum, 2015). Generally, the small, isolated or fragmented populations might experienced gene flow limitation (Warburton et al, 2000;Craft and Ashley, 2007) and mating systems alteration (Kelleher et al, Ratnaningrum et al 2005; Herlihy and Eckert, 2005;Arroyo et al, 2006).…”

Floral evolution: One-sided evolution or two? A reply to Ennos

“…Thus changes in the abundance of these pollinator classes could substantially change the selection regime for floral morphology (Castellanos et al, 2003). Furthermore, temporal and spatial variation in pollinator abundances have been found to be substantial and is thus certainly not implausible (for example, Herrera, 1996;Herlihy and Eckert, 2005;Price et al, 2005;Brunet and Sweet, 2006). Changes in pollinator abundance may occur over long time periods owing to a number of factors, including changes in pollinator migration patterns, extinction of pollinators, changes in community composition or adaptation of plants to a new habitat (see Thomson and Wilson, 2008).…”