619 results — topic: Flowering & Pollination
Olfactory versus visual cues in a floral mimicry system
It is found that pseudoflower fragrance can attract visitors by itself, and the ability of insects to differentiate pseudoflowers from true flowers by their fragrance may be important in the evolution of the mimicry system.
Archiving primary data: solutions for long-term studies.
The recent trend for journals to require open access to primary data included in publications has been embraced by many biologists, but has caused apprehension amongst researchers engaged in long-term ecological and evolutionary studies. A worldwide survey of 73 principal investigators (Pls) with lo
Stonefly predation along a hydraulic gradient: a test of the harsh-benign hypothesis
SUMMARY. 1. Microhabitat preferences of predatory stoneflies and four prey taxa were assessed by taking benthic samples along a hydraulic gradient in a Black Forest stream in West Germany. Densities of predator and prey species were estimated at twenty‐one hydraulic regimes.2. Enclosures containing
Pollinator specialization: from the individual to the community
Most spermatophytes need conspecific pollen in order to produce seed. This need for specialization seems to conflict with the generalized nature of most plant–pollinator interactions. Specialization and generalization are dynamic – not fixed – and exist simultaneously in multiple states at different
Duration of snow cover and its influence on life-history variation in yellow-bellied marmots
We evaluated the relationship between growing-season phenology, as indicated by time of snow melt, and intrapopulation variation in reproduction and growth of yellow-bellied marmots. The time of snow melt explained significant proportions of the variation in frequency of reproduction (78%), litter s
Experimental studies of pollen carryover: hummingbirds and Ipomopsis aggregata
It is concluded that presence of pollen on recipient flowers significantly reduces the average number of subsequent flowers reached by donor pollen.
Eggs, enzymes, and evolution - natural genetic variants change insect fecundity
Phosphoglucose isomerase genotypes in the butterfly Colias differ dramatically in biochemical properties. These differences were evaluated earlier, using metabolic network theory, to predict, successfully, their effects on glycolytic metabolism and hence on Colias flight capacity and several consequ
DNA methylation networks underlying mammalian traits
Using DNA methylation profiles ( n = 15,456) from 348 mammalian species, we constructed phyloepigenetic trees that bear marked similarities to traditional phylogenetic ones. Using unsupervised clustering across all samples, we identified 55 distinct cytosine modules, of which 30 are related to trait
Optimal foraging in bumblebees: hunting by expectation
Predictions of the three hypotheses concerned with hunting by expectation were tested experimentally by varying the quality of plants (amount and distribution of nectar) encountered by bumblebees (Bombus appositus).
Herbivore effect on stature, fruiting and leaf dynamics of a native crucifer
The impact of a native, leaf—feeding chrysomelid beetle (Phaedon sp. nr. oviformis) on bittercress (Cardamine cordifolia: Cruciferae), was evaluated in an exclusion experiment. Multivariate statistical analysis showed a significant increase in plant performance in the rotenone exclusion compared to
Variation in nectar robbing over time, space, and species
Variation in the interactions between a nectar-robbing bumblebee and its host plants may have important consequences with respect to the population dynamics of host plants as well as selection on floral and flowering traits.
Effects of size at metamorphosis on stonefly fecundity, longevity, and reproductive success
The data suggest that selection pressures determining body size at metamorphosis may operate independently on males and females, resulting in evolution of sexual size dimorphism, protandry, and mating early in the adult stage.
Evolution of sociality in marmots
The 14 species of marmots ( it Marmotd /it ) can be placed in one of four social systems: solitary; female kin matriline; adult male with two females and immature offspring; and a family group consisting of a territorial pair, subordinate adults, and immature offspring. Body size and hibernation are
Plant community composition mediates both large transient decline and predicted long-term recovery of soil carbon under climate warming
We integrated two methods, experimental heating and observations across natural climate gradients, to elucidate both short‐ and long‐term climatic controls on ecosystem carbon storage and to investigate carbon‐cycle feedbacks to climate in montane meadows. A 10‐year heating experiment warmed and dri
Effects of snowpack on the timing and abundance of flowering in Delphinium nelsonii: implications for climate change
Delphinium nelsonii is an early‐blooming herbaceous perennial of montane western North America, which we studied in dry subalpine meadows in the Colorado Rocky Mountains. We examined the effects of variation in annual snowfall between 1973 and 1989 on the timing and abundance of flowering. During ye
Pollinator choice and stabilizing selection for flower color in Delphinium nelsonii
Changing Climate Drives Divergent and Nonlinear Shifts in Flowering Phenology across Elevations
Climate change is known to affect regional weather patterns and phenology; however, we lack understanding of how climate drives phenological change across local spatial gradients. This spatial variation is critical for determining whether subpopulations and metacommunities are changing in unison or
Bioenergetics and evolutionary genetics: opportunities for new synthesis
Bioenergetics, the study of energy flow through living systems, may be helpful in the study of evolutionary genetics, at least for those loci concerned with resource processing in metabolism. Energy flow through organisms is sensitive to resource supply and demand, to parameters of metabolic organiz
Experimental manipulation of plant density and its effect on pollination and reproduction of two confamilial montane herbs
In three replicate experiments with D. nuttallianum, pollinator visitation rate and seed set were indistinguishable in sparse and dense arrays, consistent with the interpretation that environmental quality contributed to the earlier result in natural populations of this species.
Skewed flowering distributions and pollinator attraction
The temporal distributions of flowering by animal—pollinated plant populations, flowering curves, can be viewed profitably as resource utilization functions. A conceptual model of plant competition for pollinators suggests that selection may favor asymmetrical, positively skewed curves, and that suc
