Honeybees

A team of Harvard biologists has come closer to cracking the mystery of honeybee Colony Collapse Disorder (CCD), eight years after its appearance. CCD persists in transforming bee colonies around the world into ghost towns: by the end of each winter, some colonies wind up littered with dead bees and emptied of many more, with no signs of renewal. "One of the defining symptomatic observations of CCD colonies is the emptiness of hives in which the amount of dead bees found inside the hives do not account for the total numbers of bees present prior to winter when they were alive," states the report, published May 9 in the Bulletin of Insectology.

One of the main problems with neonicotinoids is that they have a delayed toxic effect that renders small residual concentrations of the chemicals especially problematic for long-lived beneficial insects such as bees. The argument is simple enough once you grasp the implications of delayed toxicity. Allow me to digress and offer a comparison of toxic time dependence and example chemicals.

Zu diesem Ergebnis kam eine Studie der Umweltorganisation Greenpeace, bei der 35 verschiedene Pflanzen in zehn Ländern analysiert worden sind. Der Greenpeace-Report „Giftiger Garten Eden - Eine Analyse der bienenschädlichen Pestizide in Gartenpflanzen auf dem europäischen Markt“ hat verschiedene bienenattraktive Pflanzenarten wie Veilchen, Lavendel und Primeln aus Gartenzentren, Baumärkten und Supermärkten untersucht. Nur zwei der 86 Proben waren frei von Chemikalien, der Rest wies einen regelrechten Cocktail an Pestiziden auf. 14 Prozent der europäischen Proben enthielten Pestizide ohne Zulassung in der EU. Unter den am stärksten belasteten Proben fand sich eine Probe aus Österreich aus der Gärtnerei Starkl mit 15 verschiedenen Pestiziden, davon sechs, die im österreichischen Zierpflanzenbau nicht zugelassen sind. Mehr als die Hälfte der Proben wiesen Neonicotinoide auf, die EU-weit teilweise verboten wurden und laut der Umweltorganisation als „inakzeptables Risiko für Bienen und andere Bestäuber gelten“. Die Produktion in Glashäusern ist vom Verbot allerdings ausgenommen. „Gartenfreunde werden ungewollt zu Mittätern gemacht“, kritisierte Huem Otero, Landwirtschaftssprecherin von Greenpeace.

Exposure even to low levels of imidacloprid, a widely used pesticide, can harm the central nervous system of bees and may be a reason behind the global bee colony collapse, a National Taiwan University research team said yesterday in Taipei. Reports from around the world in recent years have shown that the population of wild bees has rapidly declined in many parts of the world. As bees contribute to the pollination of many crop species, ensuring production of seeds in many flowering plants and playing an important role in the ecosystem, many scientists are concerned about the rapid decline in bee colonies.

The very same pesticides accused of causing massive declines in honeybee populations are just as culpable in the loss of songbirds, finds a new report published by the American Bird Conservancy. The pesticides in question, neonicotinoids, are based on nicotine, a natural insecticide, which causes paralysis and, eventually, death in both insects and non-target animals, such as honeybees and songbirds. Introduced in the early 1990s, neonicotinoids are now the most widely used insecticides in the world. And that popularity carries a heavy burden, the report found. After analyzing more than 200 studies conducted by both independent and industry-funded scientists, the authors called for the Environmental Protection Agency (EPA) to ban these pesticides' use until a more thorough investigation into their safety is conducted. "A single corn kernel coated with a neonicotinoid can kill a songbird," said Cynthia Palmer, coauthor of the report and pesticides-program manager for the conservancy, in a statement accompanying the report. "Even a tiny grain of wheat or canola treated with the oldest neonicotinoid—called imidacloprid—can fatally poison a bird. And as little as 1/10th of a neonicotinoid-coated corn seed per day during egg-laying season is all that is needed to affect reproduction."

Nicotinic acetylcholine receptors (nAChRs) are ligand‑gated ion channels that mediate fast synaptic transmission in the insect nervous system and are targets of a major group of insecticides, the neonicotinoids. They consist of five subunits arranged around a central ion channel. Since the subunit composition determines the functional and pharmacological properties of the receptor the presence of nAChR families comprising several subunit‑encoding genes provides a molecular basis for broad functional diversity. Analyses of genome sequences have shown that nAChR gene families remain compact in diverse insect species, when compared to their nematode and vertebrate counterparts. Thus, the fruit fly (Drosophila melanogaster), malaria mosquito (Anopheles gambiae), honey bee (Apis mellifera), silk worm (Bombyx mori) and the red flour beetle (Tribolium castaneum) possess 10‑12 nAChR genes while human and the nematode Caenorhabditis elegans have 16 and 29 respectively. Although insect nAChR gene families are amongst the smallest known, receptor diversity can be considerably increased by the posttranscriptional processes alternative splicing and mRNA A‑to‑I editing which can potentially generate protein products which far outnumber the nAChR genes. These two processes can also generate species‑specific subunit isoforms. In addition, each insect possesses at least one highly divergent nAChR subunit which may perform species‑specific functions.

Since 2009 I've been writing about the plight of beleaguered honeybees due to toxic chemicals; over five billion pounds of insecticides -- one third of them are lethal neonicotinoids (neonics) thrust into our biosphere each year. Neonics are a neuro-active insecticide fashioned after nicotine, neonics poison nerves and prevent acetylcholine from enabling neurons to communicate with each other. Over 10 million commercial beehives have died since 2008 -- this is an epic worldwide problem. My colleague Dr Henk Tennekes reported the deadly effects of neonics on both soil organisms and their 'knock-on-effects' causing starvation to meadow birds and their predators Goshawks as well as contaminating waterways for many years thereafter across Western Europe. It seems that his thorough research was blatantly disregarded elsewhere around the globe by feckless government regulatory bodies. An intrepid Dr Christy Morrissey of the University of Saskatchewan set out to investigate just how wide spread the effects of neonics were across the prairies of Western Canada. Eighty to 90 percent of the wetlands she studied were contaminated with these odious poisons, which remain in toxic concentrations within the waterways for years. She too found 'knock-on-effects' in soils extending up the food chain, which reduced populations of many animals. Earthlings are knowingly annihilating the exquisite tapestry of life or Earth's biodiversity. The strength of an ecosystem depends upon the diversity of species. By killing biodiversity, we are killing ourselves; and it's happening very quickly, globally. Dr Morrissey asked some poignant questions about the food we currently produce on our globe: "Is that the cost, no birds? Or having no butterflies? Or having no bees?"