Increasing bumble bee densities in red clover seed production areas

Neonicotinoid pesticide reduces bumble bee colony growth and queen production.

Growing evidence for declines in bee populations has caused great concern because of the valuable ecosystem services they provide. Neonicotinoid insecticides have been implicated in these declines because they occur at trace levels in the nectar and pollen of crop plants. We exposed colonies of the bumble bee Bombus terrestris in the laboratory to field-realistic levels of the neonicotinoid imi...

Subalpine bumble bee foraging distances and densities in relation to flower availability.

Bees feed almost exclusively on nectar and pollen from flowers. However, little is known about how food availability limits bee populations, especially in high elevation areas. Foraging distances and relationships between forager densities and resource availability can provide insights into the potential for food limitation in mobile consumer populations. For example, if floral resources are li...

The Bumble Bee Immune Responses

effect of cobalt application on seed production in red clover (trifolium pratense l.)

a field experiment involving red clover varieties k-39, k-17, una and viola was established on an acidic (phh2o 4.8) soil to evaluate the effects of foliar application of cobalt (a beneficial nutrient for efficient nitrogen fixation) on seed yield, and on seed yield components. the foliar spray of the crop was carried out using cobalt nitrate [co(no3)2] with the treatments: one application at t...

Drastic historic shifts in bumble-bee community composition in Sweden.

The species richness of flower-visiting insects has declined in past decades, raising concerns that the ecosystem service they provide by pollinating crops and wild plants is threatened. The relative commonness of different species with shared ecological traits can play a pervasive role in determining ecosystem functioning, but information on changes in abundances of pollinators over time is la...