Bumblebees

The rusty-patched bumblebee (Bombus affinis) has not been very lucky at all in recent years. The insect, which was once common to the Eastern Seaboard and the Midwest, has disappeared from 87 percent of its historic range. Even where it does exist, its populations are as much as 95 percent smaller than they were a few decades ago. In response to this rapid decline, the Xerces Society for Invertebrate Conservation in January 2013 petitioned the U.S. Fish and Wildlife Service to list the rusty-patched bumblebee as an endangered species under the Endangered Species Act. After no action was taken, the group followed up with a lawsuit in 2014. Last week the FWS finally responded and agreed that the species may merit protection. The agency will conduct a 12-month review to determine if an Endangered Species Act listing is warranted.

On Tuesday 21 July Christian Schmidt, Germany’s Federal Minister of Agriculture, signed an urgency decree coming into immediate effect forbidding all trade, import and sowing of winterwheat seed-coated with the nicotinoids Clothianidin, Imidacloprid und Thiamethoxam. Minister Schmidt argumented the decision as necessary to prevent massive death of honey bees saying that “ with this decision honey bees will be protected from dust contaminated with insecticides. This serves the bees as an important part of nature as well as the farmers who are dependent on bees for the pollinisation of their plants.” The attached article by Klaus Wenzel, published in the Journal Entomologische Zeitschrift Heft 2-2015 in May, has been instrumental in bringing the German authorities to this decision.

The world’s population of creepy crawlies has fallen by nearly half – but that is bad news for us, experts warn. A study published in the journal Science, reveals that the number of slugs, spiders, worms and other invertebrates has fallen by 45 per cent over the past 35 years as the human population has doubled. Experts fear this will harm the planet as creepy crawlies play an important role in pollinating crops, pest control, decomposition and ensuring soil remains packed with nutrients, as well as water filtration. In the UK the number of beetles, butterflies, bees and wasps has fallen by up to 60 per cent. Experts warn that fewer insects would have a huge effect on crop production as up to 75 per are pollinated by insects, amounting to around 10 per cent of the world's food supply. And the cost of pest control without natural predators could be more than £2.6 billion pounds in the United States alone. Scientists fear a drop in the insect population could also spark a decline in birds, which prey on pests that damage crops, and amphibians, which help keep water supplies free from algae. Decreasing invertebrate numbers are also known to compromise food production due to reduced pollination, seed dispersal and insect predation.

Anthropogenic declines of animal pollinators and the associated effects on human nutrition are of growing concern. We quantified the nutritional and health outcomes associated with decreased intake of pollinator-dependent foods for populations around the world. We assembled a database of supplies of 224 types of food in 156 countries. We quantified nutrient composition and pollinator dependence of foods to estimate the size of possible reductions in micronutrient and food intakes for different national populations, while keeping calorie intake constant with replacement by staple foods. We estimated pollinator-decline-dependent changes in micronutrient-deficient populations using population-weighted estimated average requirements and the cutpoint method. We estimated disease burdens of non-communicable, communicable, and malnutrition-related diseases with the Global Burden of Disease 2010 comparative risk assessment framework. Assuming complete removal of pollinators, 71 million (95% uncertainty interval 41–262) people in low-income countries could become newly deficient in vitamin A, and an additional 2·2 billion (1·2–2·5) already consuming below the average requirement would have further declines in vitamin A supplies. Corresponding estimates for folate were 173 million (134–225) and 1·23 billion (1·12–1·33). A 100% decline in pollinator services could reduce global fruit supplies by 22·9% (19·5–26·1), vegetables by 16·3% (15·1–17·7), and nuts and seeds by 22·1% (17·7–26·4), with significant heterogeneity by country. In sum, these dietary changes could increase global deaths yearly from non-communicable and malnutrition-related diseases by 1·42 million (1·38–1·48) and disability-adjusted life-years (DALYs) by 27·0 million (25·8–29·1), an increase of 2·7% for deaths and 1·1% for DALYs. A 50% loss of pollination services would be associated with 700 000 additional annual deaths and 13·2 million DALYs. Declines in animal pollinators could cause significant global health burdens from both non-communicable diseases and micronutrient deficiencies.

We have identified 30 papers from a literature search on PubMed and Google Scholar using the following combined key words of “pollinators”, “honeybee”, “bees”, “pesticides”, or “neonicotinoids”, as of September 30, 2014, and from a cross-reference check of a report made available by European Parliament in preparation to fulfill their regulatory mandate on the issue of protecting pollinators among their membership nations. Those paper are relevant to examine the effects of sub-lethal pesticide exposures on the health of honeybees (Apis mellifera), bumblebees (Bombus terrestris), and other bees. The weight-of-evidence of this review clearly demonstrated bees’ susceptibility to insecticides, in particular to neonicotinoids, and the synergistic effects to diseases that are commonly present in bee colonies. One important aspect of assessing and managing the risks posed by neonicotinoids to bees is the chronic effects induced by exposures at the sub-lethal levels. More than 90% of literature published after 2009 directly or indirectly demonstrated the adverse health effects associated with sub-lethal exposure to neonicotinoids,including abnormal foraging activities, impaired brood development, neurological or cognitive effects, and colony collapse disorder.

Two studies published in Nature last week have raised more concerns about whether neonicotinoid pesticides adversely affect bee health. One study shows that bees are drawn to neonicotinoids, possibly because the insects catch a “buzz” from the pesticides similar to the one humans get from nicotine (2015, DOI: 10.1038/nature14414). The other study suggests that neonicotinoids affect bee behavior and growth under realistic conditions in a crop field (2015, DOI: 10.1038/nature14420).