Bumblebees

Some of Britain’s favourite wildlife is at risk of becoming extinct unless there is a new, 21st-century agricultural revolution, experts are warning. Species from hedgehogs to skylarks and birds of prey are being wiped out – in part by companies with vested interests in “destructive” factory farming, it was claimed on World Wildlife Day, which takes place today. The “alarming” declines in wildlife will threaten not just the richness of the planet but also our ability to grow food, according to the RSPB.

Rachel Carson escribió el 27 de septiembre de 1962 Primavera Silenciosa, (Silent Spring) que advertía de los efectos perjudiciales de los pesticidas en el medio ambiente -especialmente en las aves- sin saber que los polinizadores vitales para la biodiversidad y la alimentación serían uno de los más perjudicados en su libro ya culpaba a la industria química de la creciente contaminación.​ En septiembre del 2010 el Dr Toxicólogo Henk Tennekes publicó un articulo científico en una revista de toxicología, Siguió un libro….. “Un Desastre en Potencia”.

Scientists have identified infectious diseases as a key driver of bee population decline and have shown for the first time the extent to which the diseases are shared with other pollinator groups, in research published this week. Researchers from Royal Holloway, University of London, Oxford University and Cornell University have shown that viruses that are harmful to honeybees are also present in hoverfly pollinators. The study suggests that hoverflies are exposed to the same diseases, and may move the infections around when they feed from the same flowers as the honeybees.

Bumblebees (Bombus spp.) have been declining rapidly in many temperate regions of the Old World. Despite their ecological and economic importance as pollinators, North American bumblebees have not been extensively surveyed and their conservation status is largely unknown. In this study, two approaches were used to determine whether bumblebees in that region were in decline spatially and temporally.

Spring is an important period for bumble bees, as that’s when new colonies get their start. When a solitary bumble bee queen emerges from hibernation, she initiates a nest and then does the foraging work herself, until her first offspring hatch, develop into workers, and relieve her from all duties but egg laying. Thus, should any harm befall the queen in this early period, it can have ripple effects on the health of the developing colony.

In the first long-term study of New Hampshire’s bumble bee population, researchers with the New Hampshire Agricultural Experiment Station at the University of New Hampshire have found three of the state’s most important bumble bee species have experienced drastic declines and range constriction over the last 150 years, with a fourth bee also in significant decline.

We explore synergistic mortality between a neonicotinoid (clothianidin) and an ergosterol-biosynthesis-inhibitor fungicide (propiconazole) in three bee species (A. mellifera, Bombus terrestris, Osmia bicornis) following oral exposure in the laboratory. We developed a new approach based on the binomial proportion test to analyze synergistic interactions. We estimated uptake of clothianidin per foraging bout in honey bees foraging on seed-coated rapeseed fields.

Several species of bumblebees have recently experienced range contractions and possible extinctions. While threats to bees are numerous, few analyses have attempted to understand the relative importance of multiple stressors. Such analyses are critical for prioritizing conservation strategies. Here, we describe a landscape analysis of factors predicted to cause bumblebee declines in the USA.

A recent assessment of higher tier studies on the toxicity and risks of neonics in honeybees by Solomon and Stephenson reported a colony-level NOAEC of 25 μg/kg (ppb) for imidacloprid and clothianidin. The toxicity of these insecticides to honeybees is however known to be reinforced with chronic exposure, and extrapolation of time-to lethal-effect toxicity plots compiled from published studies indicate that an imidacloprid level of 0.25 ppb, i.e. one-hundredth of the reported colony NOAEC, would kill a large proportion of bees nearing the end of their life.