1,081 results — topic: Wildlife Behavior
Optimal foraging in hummingbirds: testing the marginal value theorem
To a hummingbird, clusters of flowers on inflorescences represent patches and provide an ideal situation to test prediction of optimal patch-use. The basic question is what decision rule should a hummingbird use to decide whether or not to leave an inflorescence? The hypothesis is that hummingbirds
Optimal foraging in bumblebees and coevolution with their plants
The pattern of movements of the bumblebees and the various properties of the plants appear to represent coevolved adaptations and the bumbles' movement patterns appear to be optimal in the sense that they result in the maximum net rate of energy gain to the bumbling.
Geographical distribution and biological observation of Cyphoderris (Orthoptera: Haglidae) with a description of a new species
Energetics of yellow-bellied marmot populations
The energy dynamics of 2 colonies of yellow—bellied marmots (Marmota flaviventris) were studied in the Rocky Mountains of central Colorado in 1969 and 1970. The Intake—Rejecta and Maintenance—Production models, which included an analysis of seasonal variations in energy flow parameters, yielded simi
Resource partitioning in bumblebees: experimental studies of foraging behavior
A system comprising 2 species of bumblebess (Bombus appositus and Bombus flavifrons) and 2 species of flowers (Delphinium barbeyi and Aconitum columbianum) in Gothic, Colorado, USA, was manipulated to determine whether resource utilization by each bumblebee species was influenced by the presence of
Allometry and jumping in frogs: helping the twain to meet
Reproductive strategies in the butterflies. I. Mating frequency, plugging, and egg number
Trout predation and the size composition of stream drift
Nocturnal drift of stream invertebrates is examined as a predator avoidance adaptation via the hypothesis that those taxa or growth stages which are large, and thus subject to intense predation relative to smaller forms, should be most strongly constrained to nocturnal drift activity. Smaller taxa o
Diet of brook trout (Salvelinus fontinalis Mitchill) and brown trout (Salmo trutta L.) in an alpine stream
Niche relationships among species of aphids feeding on fireweed
Three species of aphids in the genus Aphis and one in the genus Macrosiphum feed on fireweed in the Rocky Mountains of Colorado, U.S.A. These species differ in their time of colonization of fireweed, time of maximum number of colonies, feeding position on fireweed, relationships to tending ants, lif
Competition for mutualists: aphids and ants
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