(Beyond Pesticides, March 4, 2013) Two studies released on February 28th in the journal Science detail the dramatic decline of wild pollinators and their effectiveness in producing seeds and fruit on crops in comparison to domesticated honey bees. The study conducted on the effectiveness of wild pollinators, which was led by Lucas A. Garibaldi Sc.D. of Universidad Nacional de Río Negro in Argentina, collected data at 600 test fields on all continents except Antarctica for 41 crop systems.
These studies come on the heels of a possible suspension of neonicotinoid insecticides, which have been linked to Colony Collapse Disorder (CCD), by states in the European Union. In the United States action currently looks less likely, as the U.S. Environmental Protection Agency (EPA) has moved to register sulfoxaflor, which the agency has classified as “very highly toxic to bees.”
These studies note that even though large active colonies of honey bees are useful for pollination, they cannot fully replace the contributions of diverse, wild insects in plant pollinations. Dr. Garbaldi’s study calls for, among other policy recommendations, “consideration of pollinator safety as it relates to pesticide application.”
The first of these two studies, led by Laura A. Burkle Ph.D., was titled “Plant-Pollinator Interactions over 120 Years: Loss of Species, Co-Occurrence and Function.” Using historical data sets, the study found that more than half of wild bee species were lost in the 20th Century in the U.S. and that the quantity and quality of pollination services have declined through time. The study also found that mismatches between when wild pollinators were active and when flowers were active was problematic and consistent with the growth of climate change. On the positive side, the study also found that pollination systems showed flexibly in response to disturbances, however these systems are also incredibly compromised and further loses would have dire impacts. The study stated, “Further interaction mismatches and reductions in population sizes are likely to have substantial negative consequences for this crucial ecosystem service.”
The second of these studies, led by Dr. Garibaldi, was titled “Wild Pollinators Enhance Fruit Set of Crops regardless of Honey Bee Abundance.” This study also found that diversity and abundance of wild insect pollinators have declined in many areas of the world. This study then went on to examine and compare the effectiveness of wild pollinators and honey bees. The study found that wild insects pollinated crops more effectively because increases in their visitation enhanced fruit sets by twice as much as equivalent increase in honey bee visitation.
The study found that the amount of times a fruit was visited by pollinators and the amount of pollen that was deposited on the fruit affected fruit set less strongly than the quality of the pollen deposited on the fruit. On average honey bees deposited a much greater amount of pollen on fruits, however wild pollinators provided higher quality pollen, such as greater cross-pollination. Honey bees have been generally viewed as an acceptable substitute for wild pollinators; however this report highlights the importance of not just examining pollen deposits but also the amount of fruit sets. By only focusing on studies of pollen deposits, the importance of wild pollinators is understated. The study also helps stress the importance of biodiversity. Using a single species of bee, such as honey bees, as the lone pollinator of agricultural crops can leave our food system vulnerable. Lone pollinator species are more susceptible to diseases and parasites such as varroa mites, which can destabilize the colony and lead to crops being left unpollinated.
Pollinators from bats to bees have been facing greater and greater environmental pressures that limit their ability to perform critical agricultural services in the U.S. The European Union (EU), however, is looking to take steps to protect pollinators by pushing states to impose a two-year suspension of the use of neonicotinoid insecticides. The proposal, put forward at a meeting of the Standing Committee on the Food Chain and Animal Health, would restrict the application of neonicotinoids as granules, seed-treatment, or spray on crops that are attractive to bees, particularly sunflowers, rapeseed, corn, cotton, and cereal crops.
The announcement came after research conducted by the European Food Safety Authority (EFSA) indicated that three neonicotinoid insecticides””imidacloprid, clothianidin, and thiamethoxam, produced by Switzerland’s Syngenta and Germany’s Bayer, pose an unacceptable hazards to honey bees.
In its report released January 16, EFSA concludes that systemic contamination of neonicotinoid-treated crops, neonicotinoid dust exposure, and contaminated nectar and pollen contributes to declines in honey bees and weakens their hives. High risks were also identified from exposure to guttation fluid from corn for thiamethoxam.
Even in the United Kingdom, where it seems less likely that the government will suspend the use of neonicitinoids, hardware retailers B&Q, Wicks, Homebase, and other garden stores will stop stocking products with these insecticides after a campaign run by Friends of the Earth.
“We are pleased to see action being taken in the EU to protect bees from hazardous insecticides,” said Jay Feldman, Executive Director at Beyond Pesticides. “Their actions will set a precedent for future decisions at EPA.”
However, EPA has been far less receptive to acting on public demands to ban neonicitoniod insecticides. In 2012 EPA rejected a petition requesting the agency suspend the bee-killing pesticide clothianidin. EPA further jeopardized the safety of pollinators by proposing to register a new insecticide, sulfoxaflor, which the agency has classified as “very highly toxic” to honey bees.
Sulfoxaflor is a new active ingredient whose mode of action is similar to that of neonicotinoid pesticides -it acts on the nicotinic acetylcholine receptor (nAChR) in insects. Even though it has not been classified as a neonicotinoid, it elicits similar neurological responses in honey bees, with many believing that sulfoxaflor is a new generation of neonicotinoid. EPA has noted that sulfoxaflor is highly toxic to bees, and other studies are reporting inconclusive effects on bee brood development, even though high mortalities were observed.
From April 5-6, Beyond Pesticides is convening its 31st National Pesticide Forum. New Mexican honey bee inspector, president of the New Mexico Beekeepers Association, and a beekeeper for over 30 years, Les Crowder, will address the forum on organic and natural solutions for problems commonly treated with chemicals, and the role beekeepers can play in protecting biodiversity. Join us in Albuqueque, New Mexico for a discussion on strategies that we all can take to protect pollinators.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: The Guardian