It is hypothesized that the average rate of nectar production per flower for a population of plants is such than an individual plant which possesses this rate has maximum fitness (i.e., is optimal), and predictions concerning nectarProduction in scarlet gilia, a hummingbird pollinated plant are deve

Yellow-bellied marmots (Marmota flaviventris) eat a wide variety of grasses, forbs, and seeds, but do not feed on all items in proportion to their abundance in the environment. In this study, relationships between the marmot diet and estimated protein, water, caloric value, relative biomass, and tox

White adipose tissue (WAT) and plasma samples were obtained from yellow-bellied marmots (Marmota flaviventris) throughout the year. Mean plasma triacylglycerol (TG), free fatty acids (FFAs), and glycerol were determined. There was a clear increase in FFAs and decrease in mean TG and glycerol during

Several aspects of nectarivore foraging behavior have been interpreted as responses to spatial reward patchiness of the kind documented for Delphinium nelsonii floral nectar by Pleasants and Zimmerman (1979). Working with this same species over 3 yr, however, we were unable to detect substantial pat

The statistical concept of home range as applied to the recapture radius of the deer-mouse (Peromyscus) and the calculation of homerange and density of small mammals is presented.

Pianka's (1976) treatment of competition and niche theory is taken as an authoritative precis of the recent state of this school of thought, in turn aiming attention at the functional and evolutionary responses.

Pseudoflowers induced by the rust fungus Puccinia monoica on Arabis spp. are flower—like in color, shape, size, nectar production, and scent. Pseudoflowers attract insects that aid the rust's reproduction in a way that is analogous to pollination in flowering plants. I explored the effects of pathog

The newly described Gunnison sage-grouse (Centrocercus minimus) is a species of concern for management because of marked declines in distribution and abundance due to the loss and fragmentation of sagebrush habitat. This has caused remaining populations to be unusually small and isolated. We utilize

The overall sex ratio of weaned yellow-bellied marmots does not differ significantly from one. Litter size has no effect on the sex ratio of young. Stress, measured by eosinophil concentration and mirror-image stimulation, is not associated with biased sex ratios. Three-year-old females and females

The periodic cycles in populations of microtine rodents and hares are considered together to provide the suggestion that the natural period is endogenous and size-dependent, and may be a consequence of the physiological and reproductive pace of the life cycle that scales as the fourth root of body m

Values increased with increasing size of the predator, and inclusion of the C/A term indicated that predators would obtain greater reward from small relative to large prey, and from dipterans relative to mayflies.

The bottom-up effects of plant food quality and quantity can affect the growth, survival, and reproduction of herbivores. The larvae of solitary bee pollinators, consumers of nectar and pollen, are also herbivores. Although pollen quantity and quality are known to be important for larval growth, lit

SUMMARYEight new species of the fungal order Harpellales from the United States are described, including three new monotypic genera (Genistellospora, Trichozygospora, and Simuliomyces). Three species are from black-fly larvae (Genistellospora homothallica, Simuliomyces microsporus, Pennella angustis

The timing of life events (phenology) can be influenced by climate. Studies from around the world tell us that climate cues and species' responses can vary greatly. If variation in climate effects on phenology is strong within a single ecosystem, climate change could lead to ecological disruption, b

An outstanding goal in speciation research is to trace the mode and tempo of the evolution of barriers to gene flow. Such research benefits from studying incipient speciation, in which speciation between populations has not yet occurred, but where multiple potential mechanisms of reproductive isolat

AbstractQuestionsIs it possible to predict the composition of local plant assemblages? Trait‐based approaches have offered some promise, especially in cases where deterministic processes such as environmental filtering and niche differentiation shape communities. In this study, we asked how much int

Journal Article The Annual Cycle and Fat Storage in Two Populations of Golden-Mantled Ground Squirrels Get access Barbara Hibbs Blake Barbara Hibbs Blake Department of Biology, Yale University, New Haven, Connecticut Search for other works by this author on: Oxford Academic Google Scholar Journal of

Extrapolation of the results suggests that six of the seven extant populations of this species may have effective sizes low enough to induce inbreeding depression and hence that translocations may be needed to supplement genetic diversity.

Early Proterozoic supracrustal rocks near Gunnison and Salida, Colorado include tholeiitic basalt, dacite to rhyolite, and intercalated sedimentary rocks. These were intruded by essentially synchronous gabbroic sheets, folded, and intruded by major plutons ranging from quartz diorite to granite. Pre

Many specialist herbivores eat foods that are apparently low quality. The compensatory benefits of a poor diet may include protection from natural enemies. Several bee lineages specialize on pollen of the plant family Asteraceae, which is known to be a poor-quality food. Here we tested the hypothesi