All species have limited geographic distributions; but the ecological and evolutionary mechanisms... more All species have limited geographic distributions; but the ecological and evolutionary mechanisms causing range limits are largely unknown. That many species’ geographic range limits are coincident with niche limits suggests limited evolutionary potential of marginal populations to adapt to conditions experienced beyond the range. We provide a test of range limit theory by combining population genetic analysis of microsatellite polymorphisms with a transplant experiment within, at the edge of, and 60 km beyond the northern range of a coastal dune plant. Contrary to expectations, lifetime fitness increased toward the range limit with highest fitness achieved by most populations at and beyond the range edge. Genetic differentiation among populations was strong, with very low, nondirectional gene flow suggesting range limitation via constraints to dispersal. In contrast, however, local adaptation was negligible, and a distance-dependent decline in fitness only occurred for those populations furthest from home when planted beyond the range limit. These results challenge a commonly held assumption that stable range limits match niche limits, but also raise questions about the unique value of peripheral populations in expanding species’ geographical ranges.
Fallen branches, logs, and exposed roots (fallen branches hereafter) commonly form part of the tr... more Fallen branches, logs, and exposed roots (fallen branches hereafter) commonly form part of the trunk trail system of leaf-cutting ants that inhabit the tropical rain forest. We studied the role of fallen branches on resource discovering and on leaf transport rates in Atta cephalotes. ...
Floral traits used to attract and reward pollinators should become vestigial during the evolution... more Floral traits used to attract and reward pollinators should become vestigial during the evolution of selffertilization
from outcrossing due to the reduced fitness benefits of investing in pollinator attraction. However,
few traits have been studied, and covariation with outcrossing is rarely evaluated using genetic estimates of the
mating system. We examined covariation between petal size and color and genetic estimates of outcrossing
among populations of the yellow-flowered, bee-pollinated Camissoniopsis cheiranthifolia that exhibit striking
variation in the mating system. We measured brightness, chroma, and hue, using a spectrophotometer, and petal size, using image analysis for flowers sampled in the field from 25 populations across the species’ geographic range. Petals were brighter with higher chroma and lower hue ðless redÞ in large-flowered populations than in small-flowered populations. Petal size, brightness, and chroma also correlated positively with the proportion of seeds outcrossed estimated from marker-gene analysis for a subsample of 11 populations. Parallel changes in petal size and color in selfing populations from two climatically different regions plus the maintenance of differences in flower size and color between large- and small-flowered populations when grown in a common glasshouse environment suggests genetic differentiation in these traits associated with mating system evolution.
... Filogeografía de aves mexicanas 467 Blanca Estela Hernández-Baños, Magali Honey-Escandón, Mar... more ... Filogeografía de aves mexicanas 467 Blanca Estela Hernández-Baños, Magali Honey-Escandón, María N ... a la Ecología Molecular 1 IntroduccIón a la Ecología MolEcular Luis E. Eguiartey Valeria Souza 1 ... aplicado a su concepción actual, por ejemplo, el Dr. Jaime Mora lo usó ...
All species have limited geographic distributions; but the ecological and evolutionary mechanisms... more All species have limited geographic distributions; but the ecological and evolutionary mechanisms causing range limits are largely unknown. That many species’ geographic range limits are coincident with niche limits suggests limited evolutionary potential of marginal populations to adapt to conditions experienced beyond the range. We provide a test of range limit theory by combining population genetic analysis of microsatellite polymorphisms with a transplant experiment within, at the edge of, and 60 km beyond the northern range of a coastal dune plant. Contrary to expectations, lifetime fitness increased toward the range limit with highest fitness achieved by most populations at and beyond the range edge. Genetic differentiation among populations was strong, with very low, nondirectional gene flow suggesting range limitation via constraints to dispersal. In contrast, however, local adaptation was negligible, and a distance-dependent decline in fitness only occurred for those populations furthest from home when planted beyond the range limit. These results challenge a commonly held assumption that stable range limits match niche limits, but also raise questions about the unique value of peripheral populations in expanding species’ geographical ranges.
Fallen branches, logs, and exposed roots (fallen branches hereafter) commonly form part of the tr... more Fallen branches, logs, and exposed roots (fallen branches hereafter) commonly form part of the trunk trail system of leaf-cutting ants that inhabit the tropical rain forest. We studied the role of fallen branches on resource discovering and on leaf transport rates in Atta cephalotes. ...
Floral traits used to attract and reward pollinators should become vestigial during the evolution... more Floral traits used to attract and reward pollinators should become vestigial during the evolution of selffertilization
from outcrossing due to the reduced fitness benefits of investing in pollinator attraction. However,
few traits have been studied, and covariation with outcrossing is rarely evaluated using genetic estimates of the
mating system. We examined covariation between petal size and color and genetic estimates of outcrossing
among populations of the yellow-flowered, bee-pollinated Camissoniopsis cheiranthifolia that exhibit striking
variation in the mating system. We measured brightness, chroma, and hue, using a spectrophotometer, and petal size, using image analysis for flowers sampled in the field from 25 populations across the species’ geographic range. Petals were brighter with higher chroma and lower hue ðless redÞ in large-flowered populations than in small-flowered populations. Petal size, brightness, and chroma also correlated positively with the proportion of seeds outcrossed estimated from marker-gene analysis for a subsample of 11 populations. Parallel changes in petal size and color in selfing populations from two climatically different regions plus the maintenance of differences in flower size and color between large- and small-flowered populations when grown in a common glasshouse environment suggests genetic differentiation in these traits associated with mating system evolution.
... Filogeografía de aves mexicanas 467 Blanca Estela Hernández-Baños, Magali Honey-Escandón, Mar... more ... Filogeografía de aves mexicanas 467 Blanca Estela Hernández-Baños, Magali Honey-Escandón, María N ... a la Ecología Molecular 1 IntroduccIón a la Ecología MolEcular Luis E. Eguiartey Valeria Souza 1 ... aplicado a su concepción actual, por ejemplo, el Dr. Jaime Mora lo usó ...
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Manuscripts by Adriana Lopez-Villalobos
from outcrossing due to the reduced fitness benefits of investing in pollinator attraction. However,
few traits have been studied, and covariation with outcrossing is rarely evaluated using genetic estimates of the
mating system. We examined covariation between petal size and color and genetic estimates of outcrossing
among populations of the yellow-flowered, bee-pollinated Camissoniopsis cheiranthifolia that exhibit striking
variation in the mating system. We measured brightness, chroma, and hue, using a spectrophotometer, and petal size, using image analysis for flowers sampled in the field from 25 populations across the species’ geographic range. Petals were brighter with higher chroma and lower hue ðless redÞ in large-flowered populations than in small-flowered populations. Petal size, brightness, and chroma also correlated positively with the proportion of seeds outcrossed estimated from marker-gene analysis for a subsample of 11 populations. Parallel changes in petal size and color in selfing populations from two climatically different regions plus the maintenance of differences in flower size and color between large- and small-flowered populations when grown in a common glasshouse environment suggests genetic differentiation in these traits associated with mating system evolution.
from outcrossing due to the reduced fitness benefits of investing in pollinator attraction. However,
few traits have been studied, and covariation with outcrossing is rarely evaluated using genetic estimates of the
mating system. We examined covariation between petal size and color and genetic estimates of outcrossing
among populations of the yellow-flowered, bee-pollinated Camissoniopsis cheiranthifolia that exhibit striking
variation in the mating system. We measured brightness, chroma, and hue, using a spectrophotometer, and petal size, using image analysis for flowers sampled in the field from 25 populations across the species’ geographic range. Petals were brighter with higher chroma and lower hue ðless redÞ in large-flowered populations than in small-flowered populations. Petal size, brightness, and chroma also correlated positively with the proportion of seeds outcrossed estimated from marker-gene analysis for a subsample of 11 populations. Parallel changes in petal size and color in selfing populations from two climatically different regions plus the maintenance of differences in flower size and color between large- and small-flowered populations when grown in a common glasshouse environment suggests genetic differentiation in these traits associated with mating system evolution.