Maternal characteristics, social dynamics, and environmental factors can all influence reproduction and survival as well as shape trade-offs that might arise between these components of fitness. Short-lived mammals like the golden-mantled ground squirrel (GMGS; Callospermophilus lateralis) tend to m

Data were collected as part of a study of population dynamics of solitary, cavity-nesting Hymenoptera. Nesting structures ("trap-nests") were established at five study sites along an elevational gradient around the Rocky Mountain Biological Laboratory in 2013. Two additional study sites were added i

For a brief period in 1981 Bombus appositus queens visited Ipomopsis aggregata, a hummingbird-pollinated species with floral characteristics typical of that pollination syndrome. This behavior was not observed in other years. Despite the fact that Ipomopsis lacks floral features associated with bee

Behavioral experiments were carried out in flow-through observation boxes in New York and Colorado streams to determine whether interactions between pairs of predaceous stoneflies were characterized by exploitative or interference competition and to determine the effect of prey density on such inter

Experiments in Colorado and New York streams assessed the effects of predaceous stoneflies on benthic invertebrate community establishment in enclosures providing uncolonized habitat. Aspects of prey community structure measured were density, species richness, relative species abundance, and body si

A major link between larval ecology and mating systems in butterflies is the environment in which larvae hatch. It determines when a female should lay her eggs, and therefore when she will be receptive to mating. The fitness of males is determined chiefly by access to fertilizable females, and there

Sympatric plant species can compete for pollination services in several ways. For example, pollinators may move between species and deposit heterospecific pollen on stigmas, which in turn may reduce the efficacy of conspecific pollen. We explored this possibility by determining the effect of Delphin

Model and experimental results suggest that, in certain wing regions, increased melanization can reduce body temperature in Pieris; this effect of melanization is exactly the opposite of that found in other Pierid butterflies that use their wings as solar absorbers.

Results show that Pieris require thoracic temperature in order to take off and fly, and achieve these elevated temperatures by basking, and suggest that a re-evaluation of the functional significance of melanization in Pieris is needed.

Patterns of egg distribution and survivorship were examined for six generations of a univoltine population of the pierid butterfly Colias alexandra, finding that among clumped individuals, survivorship is two times greater for the first or previously-laid individual than the second or subsequently-

Pollinators that forage indiscriminately can transfer pollen from one species to another, reducing the amount that reaches conspecific flowers. I present evidence that the presence of another plant species visited by the same pollinators can also reduce pollen dispersal distances and outcrossing. Th