Ethan A. Huff
August 29, 2013
Three more agricultural pesticides have been added to the growing list of known chemical poisons killing honeybees, thanks to a new study published in the journal Environmental Toxicology and Chemistry. Researchers associated with the non-profit group Society of Environmental Toxicology and Chemistry (SETAC) found that even sublethal doses of three commonly-used insecticides harm bees in substantial ways that can lead to colony collapse disorder (CCD) and other mass die-off events.
For their research, Dr. Stephan Caravalho and his colleagues from both the Universidade Federal de Lavras in Brazil and the Institut Nationale de la Recherche Agronomique in France tested the physiological effects of deltamethrin, fipronil and spinosad on the Apis mellifera variety of honeybee. The three chemicals were applied to the bees in varying dosages to test for damage caused and to observe mortality rates.
What they found is that, regardless of dosage, the agricultural chemicals noticeably damaged the health of honeybees in numerous key ways. Besides harming their immune systems, the three chemicals were also found to alter the bees’ cognitive capacities as well, the healthy functioning of which is required for bees to properly forage and maintain accurate physical orientation.
“Deltamethrin, fipronil and spinosad, widely used pesticides in agriculture and home pest control, were applied to healthy honeybees and proved toxic to some degree irrespective of dosage,” explains a EurekAlert! announcement about the study. “At sublethal doses, the pesticides modulated key enzymes that regulate physiological processes, cognitive capacities and immune responses, such as homing flight, associative learning, foraging behavior and brood development.”
Deltamethrin is a pyrethroid insecticide commonly used in home bed bug sprays and ant killer dusts, and is also used to treat outdoor areas like golf courses and gardens, while fipronil is a broad-spectrum insecticide commonly used on commercial crops. Spinosad is typically used in the treatment of home gardens and plant beds, and is even sometimes used to treat head lice in children.
A myriad of science cannot be wrong: Insecticides of many varieties are killing off bees
This study is just one of many in recent years to identify a link between pesticide use and the mysterious disappearance and death of millions of bees worldwide. Other recent studies have found that neonicotinoid pesticides like imidacloprid are also toxic to bees, as are pyrethroid and a host of other organophosphate insecticides.
“[P]esticides have consistently been implicated as a key issue in pollinator declines, not only through immediate bee deaths, but also through sublethal exposure causing changes in bee reproduction, navigation and foraging,” explains the non-profit group Beyond Pesticides. “These chemicals have implications for bees, other pollinators like bumblebees and hummingbirds, as well as organisms that are beneficial to the environment.”
Beyond Pesticides has put together a thorough listing of recent studies that highlight the dangers of pesticides for bees. You can view this listing here:
You can also view the full abstract for the recent study on deltamethrin, fipronil and spinosad here:
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This article was posted: Thursday, August 29, 2013 at 10:05 am