This dataset represents an estimate of the day of year (i.e. , "Julian Day") of the onset of the seasonal snowpack. Specifically these are estimates of the last day of bare ground derived from long-term time-series of Landsat TM, ETM, and OLI imagery starting in 1993. To facilitate computation of sn

This dataset represents an estimate of the day of year (i.e. , "Julian Day") of the persistence of the seasonal snowpack. Specifically these are estimates of the first day of bare ground derived from long-term time-series of Landsat TM, ETM, and OLI imagery starting in 1993. These maps combine month

The arrival-departure process of bees on flowers and the immigration-extinction process of species on islands are contrasted, and the value of the stochastic, species-level approach to community composition is briefly discussed.

ABSTRACTThe reservoir cytoskeleton of Colacium Ehrenberg is formed of three bands of microtubules. The microtubules of the dorsal band (DMT) become doublets and are continuous with the longitudinal microtubules of the canal and, therefore, of the pellicle. A band of para‐reservoir microtubules (PMT)

The observations support the hypothesis that the phagotrophic euglenoids arose from a bondonid ancestor and gave rise to the phototrophs by chloroplast acquisition.

Abstract. 1. Mating patterns in a natural population of checkerspot butterflies, Euphydryas editha Boisduval, were investigated by dusting male external genitalia with fluorescent dyes and examining mated females under UV light. 2. These dyes may have diverse applications in studies of insect popula

ABSTRACT Male mating success as a function of genotype is an important fitness component. It can be studied in wild populations, in species for which a given group of progeny has exactly one father, by determining genotypes of wild-caught mothers and of sufficient numbers of their progeny. Here, we

Bioenergetics, the study of energy flow through living systems, may be helpful in the study of evolutionary genetics, at least for those loci concerned with resource processing in metabolism. Energy flow through organisms is sensitive to resource supply and demand, to parameters of metabolic organiz

In all of 16 experimental replicates discrimination against albinos was reduced or eliminated after painting, and albino handling times declined toward values for blue-flowered inflorescences, indicating that an inferior nectar guide increases the energetic cost of foraging at albino.

Reciprocal seed transplants suggest that there is fine‐scale adaptation in Colorado populations of the perennial herb Delphinium nelsonii. In four experimental plots, seeds planted within 1 m of the maternal parent produced seedlings that began flowering at a younger age and produced more flowers ov

Genetic variability at 27 loci was analyzed in four populations of pikas (Ochotona princeps) from Colorado. Estimates of mean heterozygosity [Formula: see text] ranged from 0.5 to 1.4%. These results are among the lowest estimates of [Formula: see text] reported for a mammal having a broad distribut

In bumblebee visits to flowers of Erythronium grandiflorum (Liliaceae), the ratio of self‐ to nonself‐ (“outcross”) pollen grains deposited on the stigma is positively correlated with the degree of stylar exsertion beyond the anthers. Natural populations show substantial, continuous variation in sty