Small vertebrates were recovered from the matrix encasing specimens of giant sauropod dinosaurs (Supersaurus, Ultrasaurus, Dystylosaurus) collected from the “Dry Mesa” Quarry (Brushy Basin Member, Morrison Formation, western Colorado). Most of the remains appear to pertain to a single form of pterod

AbstractHabitat selection may have population level consequences and ultimately may influence a population's local persistence or extinction. We capitalized on a long‐term study (1962–2004) of yellow‐bellied marmotsMarmota flaviventrisin and around the Rocky Mountain Biological Laboratory, Gothic, C

The Ipomopsis aggregata species complex (Polemoniaceae) includes species pairs that hybridize readily in nature as well as pairs that meet along contact zones with no apparent hybridization. Artificial hybrids can be made between I. aggregata and I. arizonica, yet morphological intermediates between

We simulated pollination in a plant population and explored how pollen dispersal distance and allocation among recipient individuals evolved in response to direct selection on three loci coding for dispersal phenotype and in response to indirect selection on two unlinked "genetic congruence" loci. F

Aquilegia elegantula Greene and A. caerulea James occur in montane and subalpine habitats in the southern Rocky Mountains of western North America. The red and yellow flowers of A. elegantula are nodding, odorless, protogynous, and secrete a concentrated (44%) sucrose nectar in the floral spurs. See

Macrophage polarization refers to how macrophages have been activated at a given point in space and time. Polarization is not fixed, as macrophages are sufficiently plastic to integrate multiple signals, such as those from microbes, damaged tissues, and ...Read More

Abstract Temporal correlations among demographic parameters can strongly influence population dynamics. Our empirical knowledge, however, is very limited regarding the direction and the magnitude of these correlations and how they vary among demographic parameters and species’ life histories. Here,

A survey of approximately 60 ponds in the Gunnison Basin, Gunnison and Pitkin counties, Colorado, U.S.A., showed a cor- relation between the thermal ranges of the ponds and the life history pattern of Ambystoma tigrinum populations. Characterization of physical and biotic parameters allowed a rankin

Abstract. 1. Foraging effort can vary among age classes and between the sexes. In many Lepidoptera, young males feed from mud, dung or carrion in a behaviour known as ‘puddling’, whereas females rarely puddle. In at least one species, males transfer sodium gained from puddling to females at mating f

Hypothetically, flowers which have coevolved with pollination by hummingbirds could provide both energy and water balance simultaneously if they produced nectars of appropriate concentrations which depend upon environmental temperature.

Mutualistic networks are key for the creation and maintenance of biodiversity, yet are threatened by global environmental change. Most simulation models assume that network structure remains static after species losses, despite theoretical and empirical reasons to expect dynamic responses. We assess

Abstract In the early 1900s, tree-ring scientists began analyzing the relative widths of annual growth rings preserved in the cross sections of trees to infer past climate variations. Now, many ring-width index (RWI) chronologies, each representing a specific site and species, are archived online wi

1. The extent to which flower colour and other visual cues influence butterfly flower choice in the field is poorly understood, especially in comparison with choices by Hymenoptera. 2. Using a novel approach to studies of visitation behaviour by butterflies, flower colour of four Asteraceae species

Assessment of the quality of different ant species as partners of the facultatively myrmecophilous lycaenid butterfly Glaucopsyche lygdamus found that F. obscuripes may act as a parasite of the general association between G. lyg damus and ants under certain conditions.

Two sympatric Delphinium species, D. barbeyi and D. nuttallianum, are ecologically and morphologically similar. However, D. barbeyi has multiple, large inflorescences while D. nuttallianum has a single, small inflorescence. These differences in floral display should result in greater intraplant poll

Summary Leaf venation networks provide an integrative linkage between plant form, function and climate niche, because leaf water transport underlies variation in plant performance. Here, we develop theory based on leaf physiology that uses community‐mean vein density to predict growing season temper

Many animal signals are complex, often combining multimodal components with dynamic motion. To understand the function and evolution of these displays, it is vital to appreciate their spatiotemporal organization. Male broad-tailed hummingbirds (Selasphorus platycercus) perform dramatic U-shaped cour

It is concluded that either temporal differences or size differences of copepodids and adults would allow coexistence and that extreme size differences are probably unimportant compared to morphological differences of feeding appendages and perhaps behavioral differences.

Dinosaur footprint casts from a Mesaverde (Campanian) coal mine near Gunnison, Colorado resemble those of the notorious "mystery dinosaur, Xosaurus" which was probably a giant hadrosaur. Existing footprint descriptions, although obscure and hard to verify, are too important to overlook, particularit

Investigation of this mating system in Epeerus longimanus, a mayfly of the western United States that forms swarms that are quite large, finds that swarm locations are not explainable as feeding or emergence sites, but they do correlate with landscape features.