Queen bumblebees (Bombus appositus) leave nectar behind in Delphinium nelsoni flowers with high-standing crops of nectar, and residues predicted by an optimal feeding hypothesis agree with field measurements.

Here, we present estimates of heritability and selection on network traits in a single population, allowing us to address the evolutionary potential of social behavior and the poorly understood link between sociality and fitness. To evolve, sociality must have some heritable basis, yet the heritabil

While community‐weighted means of plant traits have been linked to mean environmental conditions at large scales, the drivers of trait variation within communities are not well understood. Local environmental heterogeneity (such as microclimate variability), in addition to mean environmental conditi

Bees did not perform exactly as the marginal value theorem predicted they should to maximize their rate of net energy intake, which strongly implies that optimal foraging models which predict a shift in any particular behavior in response to environmental conditions are too simplistic to accurately

We studied the timing and abundance of flowering by Androsace septentrionalis L. (Primulaceae), an indeterminate winter annual or short‐lived perennial, in 2 × 2 m plots at the Rocky Mountain Biological Laboratory in Colorado, USA, from 1982 to 2000. Flowers were counted every other day for most or

The study of mutualistic interaction networks has led to valuable insights into ecological and evolutionary processes. However, our understanding of network structure may depend upon the temporal scale at which we sample and analyze network data. To date, we lack a comprehensive assessment of the te

It was found that the slopes of linear dye carryover functions generally became more shallow as floral variability increased; this led to substantially longer carryover in the treatment with greatest variability, and total amounts of dye transferred did not appear to be sensitive to the degree of va

Alpine species are among those most threatened by climatic shifts due to their physiological and geographic constraints. The American pika (Ochotona princeps), a small mammal found in mountainous, rocky habitats throughout much of western North America, has experienced recent population extirpations

The effort necessary to measure the differences in lifetime reproductive success in nature has already been described convincingly (20). All impregnations, births, and deaths that occur throughout the entire turnover of a wild population must be recorded. This process is both necessary and fascinati

Unusual spring weather climaxed by a late June snowstorm in the subalpine area around Gothic, Gunnison County, Colorado, had a profound effect on the biota. Damage to herbaceous prennial plans was extensive and the size of insect and small mammal populations was depressed. The storm caused the extin

Human activities have caused the decline of numerous species and ecosystems. To promote ecosystem resilience, recent management efforts aim to maintain ecosystem patterns and processes within their historical range of variability. There has been substantial concern that quaking aspen, the most widel

Biological processes, such as predator-prey or competitive interactions, occur at multiple spatial and temporal scales, but their impacts on the distribution, abundance, and fitness of organisms may only be detectable at some scales. This is because 1) small scale (local) processes may be constraine

Changing sex ratiosClimate-warming temperatures might be expected to affect the sex ratio of species if sex determination is temperature-dependent. Petryet al.show that indirect climate effects could also alter sex ratios in species in which sex is genetically determined and damage reproductive fitn

AbstractSimultaneous or sequential attack by herbivores and microbes is common in plants. Many seed plants exhibit a defence trade‐off against chewing herbivorous insects and leaf‐colonizing (‘phyllosphere’) bacteria, which arises from cross‐talk between the phytohormones jasmonic acid (JA, induced

AbstractMany animals assess their risk of predation by listening to and evaluating predators' vocalizations. We reviewed the literature to draw generalizations about predator discrimination abilities, the retention of these abilities over evolutionary time, and the potential underlying proximate mec

In Senecio, flowering phenology patterns and differences among pollinators in foraging behavior may have more important consequences for seed set and gene flow patterns than plant density or plant size.

The movements of hummingbirds between inflorescences of scarlet gilia exhibited the following patterns: Although the hummingbirds appeared to avoid moving to the previous inflorescence, no significant correlation was found between the directions of successive inter-inflorescence movements.

This study examines the organization of communities whose populations are distributed among ephemeral habitat patches and the frequent molting of the crustacean exoskeleton keeps these epibiont populations in a state of constant renewal.

McIntosh. A. R. and Peckarsky, B. L. 1999. Criteria determining behavioural responses to multiple predators by a stream mayfly - Oikos 85: 554-564. We investigated prey responses to multiple predators by observing drift and positioning of Buetis bicuudctrus (Ephemeroptera: Baetidae) nymphs in the pr

A widespread volcanic field covered most of the Southern Rocky Mountains in middle Tertiary time, 40 to 25 m.y. ago (approximately Oligocene time). This field covered an erosion surface that beveled structures formed during the Laramide orogeny in Late Cretaceous and early Tertiary time. The source