New research published in Environmental Toxicology and Chemistry addresses the effects of two broad-spectrum systemic insecticides, fipornil and imidacloprid, on honeybees.
These insecticides are widely used in agriculture, and the authors conclude that fipronil and imidacloprid are inhibitors of mitochondrial bioenergetics, resulting in depleted cell energy. This action can explain the toxicity of these compounds for honeybees.
Scientists are urgently trying to determine the causes of colony collapse disorder and the alarming population declines of honeybees. The cross-pollination services they provide are required by approximately 80 percent of all flowering plants, and 1/3 of all agricultural food production directly depends on bee pollination. As a result, there has been a flurry of research on honeybee parasitic mite infestations, viral diseases, and the direct and indirect impacts of pesticides.
The effects of pyrazoles (e.g., fipronil) and neonicotinoids (e.g., imidacloprid) on the nervous system are fairly well documented. Daniel Nicodemo, professor of ecology and beekeeping at the Universidade Estadual Paulista in Dracena, Brazil, and lead author of the study states, "These insecticides affect the nervous system of pest and beneficial insects, often killing them.
Sublethal effects related to insect behavior have been described in other studies; even a few nanograms of active ingredient disturbed the sense of taste, olfactory learning and motor activity of the bees." A key characteristic of colony collapse disorder is the incapacity of the honeybees to return to their hives, and these disruptions have a direct impact on that ability.
In this study, Nicodemo et al. looked at the effects of fipronil and imidacloprid on the bioenergetics functioning of mitochondria isolated from the heads and thoraces of Africanized honeybees. Mitochondria are the power plants of a cell, generating most of a cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy.
Honeybee flight muscles are strongly dependent on high levels of oxygen consumption and energy metabolism. Mitochondrial oxidative phosphorylation drives ATP synthesis, which is required to contract the muscles during flight. "If something goes wrong, the energy production is impaired," explains Nicodemo. "Similar to a plane, honeybees require clean fuel in order to fly."
Both fipronil and imidacloprid negatively affected the mitochondrial bioenergetics of the head and thorax of the honeybees. While at sublethal levels, insecticide damage may not be evident, even such low level exposure clearly contributes to the inability of a honeybee to forage and return to the hive, which could result in declining bee populations.
Jennifer Lynch | Eurek Alert!
Gasoline from a nanoreactor
01.04.2015 | Paul Scherrer Institut (PSI)
Lizard activity levels can help scientists predict environmental change
01.04.2015 | University of Missouri-Columbia
Spring is here and ectotherms, or animals dependent on external sources to raise their body temperature, are becoming more active. Recent studies have shown...
Glass-fronted office buildings are some of the biggest energy consumers, and regulating their temperature is a big job. Now a façade element developed by Fraunhofer researchers and designers for glass fronts is to reduce energy consumption by harnessing solar thermal energy. A demonstrator version will be on display at Hannover Messe.
In Germany, buildings account for almost 40 percent of all energy usage. Heating, cooling and ventilating homes, offices and public spaces is expensive – and...
Outstanding chemical, thermal and tribological properties predestine silicon carbide for the production of ceramic components of high volume. A novel method now overcomes the procedural and technical limitations of conventional design methods for the production of components with large differences in wall thickness and demanding undercuts.
Extremely hard as diamond, shrinking-free manufacturing, resistance to chemicals, wear and temperatures up to 1300 °C: Silicon carbide (SiSiC) bundles all...
In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...
The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.
As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...
25.03.2015 | Event News
19.03.2015 | Event News
17.03.2015 | Event News
01.04.2015 | Life Sciences
01.04.2015 | Process Engineering
01.04.2015 | Agricultural and Forestry Science