The mean diameter of viable pollen grains is approximately 13 μm greater than the mean diameter of inviable grains in Mimulus guttatus. We show that this difference is large enough to be detected by particle counters and that these machines can be used to obtain a rapid estimate of pollen viability. While requiring a separate calibration, a size-based statistic is also strongly correlated with ...

Organisms exhibit an incredible diversity of life history strategies as adaptive responses to environmental variation. The establishment of novel life history strategies involves multilocus polymorphisms, which will be challenging to establish in the face of gene flow and recombination. Theory predicts that adaptive allelic combinations may be maintained and spread if they occur in genomic regi...

Resumen.—La tasa de acumulación de recursos energéticos por parte de las aves que se encuentran en migración puede indicar la calidad del hábitat en los sitios de paradas migratorias. Sin embargo, se sabe poco sobre acerca de cómo los hábitos de alimentación y la disponibilidad de alimentos afectan el metabolismo de las grasas y proteínas de aves silvestres en los sitios de parada. Comparamos i...

10. CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not. ABSTRACT 11 Across western North America, Mimulus guttatus exists as many local populations adapted to site-12 specific challenges including salt spray, temperature, water availability, and soil chemistry. Gene flow 13 between locally...

Both chromosomal rearrangements and negative interactions among loci (Dobzhansky-Muller incompatibilities) have been advanced as the genetic mechanism underlying the sterility of interspecific hybrids. These alternatives invoke very different evolutionary histories during speciation and also predict different patterns of sterility in artificial hybrids. Chromosomal rearrangements require drift,...

Nearly all bees rely on pollen as the sole protein source for the development of their larvae. The central importance of pollen for the bee life cycle should exert strong selection on their ability to locate the most rewarding sources of pollen. Despite this importance, very few studies have examined the influence of intraspecific variation in pollen rewards on the foraging decisions of bees. P...