Flight initiation distance (FID), or the distance between a prey animal and an approaching intruder when the prey initiates its escape, is an important factor in wildlife management. We conducted a study on individually identified yellow-bellied marmots (Marmota flaviventris) to test 3 key assumptio

High-altitude and high-latitude sites are expected to be very sensitive to global warming, because the biological activity of most plants is restricted by the length of the short snow- free season, which is determined by climate. Long-term observational studies in subalpine meadows of the Colorado R

▪ Abstract Knowledge of both prokaryotic and eukaryotic organisms is essential to the study of molecular evolution. Their common ancestry mandates that their molecular functions share many aspects of adaptation and constraint, yet their differences in size, ploidy, and structural complexity also giv

A Daphnia rosea population was observed over a 2—year period in order to compare mortality with natural predation pressure. A technique is presented for estimating the instantaneous death rate of Daphnia from population dynamics data as derived from quantitative, serial, plankton samples. The effect

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Chemically defended plant tissues present formidable barriers to herbivores. Although mechanisms to resist plant defenses have been identified in ancient herbivorous lineages, adaptations to overcome plant defenses during transitions to herbivory remain relatively unexplored. The fly genus Scaptomyz

Predation on lupine flowers by larvae of a lycaenid butterfly was studied by comparison of inflorescences exposed to and protected from infestation, and by comparison of lupine populations exposed to different degrees of attack. The lycaenids caused striking reduction in seed set, indicating that th

Abstract North America has more than 4000 bee species, yet we have little information on the health, distribution, and population trends of most of these species. In the United States, what information is available is distributed across multiple institutions, and efforts to track bee populations are

Comparative data from subalpine wetlands in Colorado indicate that larvae of the limnephilid caddisflies, Asynarchus nigriculus and Limnephilus externus, are reciprocally abundant among habitats–Limnephilus larvae dominate in permanent waters, whereas Asynarchus larvae dominate in temporary basins.

• Premise of the study: Darwin first proposed that species with larger ecological breadth have greater phenotypic variation. We tested this hypothesis by comparing intraspecific variation in specific leaf area (SLA) to species’ local elevational range and by assessing how external (abiotic) filters

It is shown that ants are a Limited and Limiting resource for a tended aphid species and that fireweed aphids compete with intra-and interspecific aphid neighbors for the services of ant mutualists.

Floral nectar of many plant species is prone to colonization by microbial organisms such as yeasts. Their presence and metabolism of nectar chemical components have the potential to modify a suite of floral traits important for pollinator attraction, including nectar quality and scent. However, stud

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

Research Article| March 01, 1976 Biotite-induced grussification of the Boulder Creek Granodiorite, Boulder County, Colorado DANA ISHERWOOD; DANA ISHERWOOD 1Department of Geological Sciences, University of Colorado, Boulder, Colorado 80302 Search for other works by this author on: GSW Google Scholar

Evidence is presented which supports the hypothesis that competition occurs among species of aphids for the services of ants. It is suggested that, in addition to the more familiar pollination systems, aphid–ant systems should be used for the study of competition for mutualists because aphid–ant sys

I examined the adaptive significance of two floral traits in the perennial herb, Lupinus argenteus: 1) the retention of corollas on "spent" flowers, i.e., flowers containing inviable pollen, unreceptive stigmas, and negligible pollinator rewards and 2) a change in corolla color of retained "spent" f

Summary Bee pollinators provide a critical ecosystem service to wild and agricultural plants but are reported to be declining world‐wide due to anthropogenic change. Long‐term data on bee abundance and diversity are scarce, and the need for additional quantitative sampling using repeatable methods h

• Premise of the study: Climate change has affected species worldwide, including alterations in phenology, migration patterns, distribution, and survival. Because Erythronium grandiflorum is an early‐season bloomer, alterations in its phenology may have serious implications for many North American R

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.