Search results for "bees"

Defensive Behavior of Honey Bees Toward Ants

1970

Elucidating the genetic determinism of the plasticity of seed proteins in response to the environment using Medicago truncatula

2019

International audience; Legumes are able to produce high-protein seeds without nitrogen fertilizer through root symbiosis with nitrogen-fixing rhizobia. Rich in lysine, these proteins are used for human nutrition and animal feed. However, instability of seed protein yield and quality due to environmental fluctuations limits the wide adoption of legumes in Europe. Breeding efforts are needed to optimize and stabilize seed nutritional quality. We have studied the plasticity of protein content and composition of seeds from a collection of 200 ecotypes of Medicago truncatula grown under four controlled conditions (optimal, drought, and winter/spring sowing). A quantitative analysis of one-dimen…

A landscape-scale approach for linking farming strategies to weed communities and their contribution to ecosystem services

2019

National audience; Weeds present in agricultural fields provide habitats and trophic resources and as such contribute to the provision of ecosystem services such as pollination (quantity and quality of pollen and nectar in flowers) and biological control (seeds for pest natural enemies). The nature and amount of services provided depends on the floral composition of weed communities and this composition is driven by the combination of farming practices. Linking farming strategies to services is thus an important step to provide management guidelines for enhancing ecosystem services. We report here on such an analysis, based on agronomical and weed data collected annually in 70 field cores a…

Floral Diversity and Pollen Transfer Mechanisms in Bird-pollinated Salvia Species

2007

† Background and Aims Bird-pollinated (ornithophilous) Salvia species (sages) transfer pollen either by means of a staminal lever mechanism or by immovable stamens. As the distribution of the two modes within the genus is not known, we present a survey of all ornithophilous sages. The main focus is given to floral diversity especially with respect to functional lever morphology. Thereby the hypothesis is tested that, due to a pollinator shift from bees to birds, the lever mechanism became unnecessary. † Methods To get a general idea about the diversity of pollen transfer mechanisms, 186 ornithophilous Salvia species were classified according to the functional morphology of the stamen and th…

Determination of pesticide residues in honey bees, pollen and beeswax: assessing pesticide hazard in spanish apiaries

2020

Pollinator decline is an emerging worldwide problem with serious repercussions on agriculture and environment. Around one third of human food relies on insect pollination, and most of the flowering plants need pollinators to survive. Honey bee is the main pollinator in environments where anthropogenic pressure has reduced the number of native pollinators, like urban, rural and agricultural areas. The main cause of beekeeping crisis is parasite Varroa destructor and secondary infections associated with the mite. Pesticide contamination and nutritional deficiencies, combined with the parasite, can act synergistically and reduce survival of bee colonies. Honey bees patrol extensive areas when …

Transfer of Immunity from Mother to Offspring Is Mediated via Egg-Yolk Protein Vitellogenin.

2015

Insect immune systems can recognize specific pathogens and prime offspring immunity. High specificity of immune priming can be achieved when insect females transfer immune elicitors into developing oocytes. The molecular mechanism behind this transfer has been a mystery. Here, we establish that the egg-yolk protein vitellogenin is the carrier of immune elicitors. Using the honey bee, Apis mellifera, model system, we demonstrate with microscopy and western blotting that vitellogenin binds to bacteria, both Paenibacillus larvae – the gram-positive bacterium causing American foulbrood disease – and to Escherichia coli that represents gram-negative bacteria. Next, we verify that vitellogenin bi…

Brains burning fat: Different forms of energy metabolism in the CNS of insects

1983

Habitat area and local habitat conditions outweigh fragmentation effects on insect communities in vineyards

2022

Fragmentation of habitat, for example by intensive agricultural practices, can be detrimental to local biodiversity. However, it often remains unclear whether such biodiversity declines are caused by loss of habitat area or increased fragmentation, and how habitat quality factors into it. In our study system, vegetated vineyards are typically small, and isolated from one another, potentially limiting the distribution and dispersal of organisms. In a full-factorial experiment of a priori selected vegetated vineyard patches of differing size and fragmentation, we aimed to disentangle the effects of habitat area (area of vegetated vineyards), habitat fragmentation (number of vegetated vineyard…