New evidence to support the link between plant and pollinator decline

The first ever Britain-wide assessment of the value of wild flowers as food for pollinators, led by the University of Bristol, shows that decreasing resources mirror the decline of pollinating insects, providing new evidence to support the link between plant and pollinator decline. In recent years, there have been considerable concerns over threats to wild bees and other insect pollinators which are vital to the success of important food crops and wild flowers. Amongst the many pressures facing pollinators, a key factor is likely to be decreasing floral resources in Britain. The study, published today in Nature combines vegetation survey data recorded over the last 80 years with modern day measurements of nectar to provide the most comprehensive assessment ever published. In the study, researchers from the University of Bristol and University of Leeds worked with scientists from the Centre for Ecology and Hydrology and Fera Science Ltd, to find substantial losses to nectar resources in England and Wales between the 1930s and 1970s – a period closely linked with agricultural intensification.

Central thesis of Henk Tennekes book "Disaster in the Making" confirmed by German entomologists

Entomologists from Krefeld, Germany performing an inventory of insects have made an alarming discovery: since 1989 the amount of insects in two places in the nature reserve Orbroicher Bruch have fallen by more than three-quarters. The researchers have performed the measurements in exactly the same way as performed in 1989; in the same place, according to the same method and by the same people. "So the data can be reliably compared", the entomologists emphasize. Two Malaise insect traps were placed in a pasture about 50 meters from each other over a period of many months to catch and weigh insects. Whereas in 1989 1.4 kg of insects were captured in this way, now less than 300 grams were recovered. According to the entomologists, this dramatic decline has serious consequences for the ecosystem: all insect-eating animals are threatened with extinction and eco-system services, including pollination, decomposition processes or soil fertility, will come under serious threat. The data from Krefeld are consistent with the Henk Tennekes thesis of 2010 that the widespread use of neonicotinoid insecticides in agriculture will wipe out insects.

Concentrations of neonicotinoid insecticides in honey, pollen and honey bees in central Saskatchewan, Canada

Neonicotinoid insecticides (NIs) and their transformation products were detected in honey, pollen and honey bees, (Apis mellifera) from hives located within 30 km of the City of Saskatoon, Saskatchewan, Canada. Clothianidin and thiamethoxam were the most frequently detected NIs, found in 68 and 75% of honey samples at mean concentrations of 8.2 and 17.2 ng g−1 wet mass, (wm), respectively. Clothianidin was also found in >50% of samples of bees and pollen. Concentrations of clothianidin in bees exceed the LD50 in 2 of 28 samples, while for other NIs concentrations were typically 10–100-fold less than the oral LD50.

Consequences of imidacloprid treatments for hemlock woolly adelgid on stream water quality in the southern Appalachians

Imidacloprid, a neonicotinoid pesticide, is commonly used in hemlock woolly adelgid, Adelges tsugae (Annand) (HWA) (Hemiptera: Adelgidae), pest management programs to preserve hemlock resources. Great Smoky Mountains National Park (GRSM) has an extensive HWA integrated pest management program, with more than 200,000 individual hemlocks in the Park having received imidacloprid soil treatments. A retrospective study was conducted in cooperation with GRSM to assess imidacloprid and two of its insecticidal metabolites (5-hydroxy and olefin) are present in surface waters (i.e., streams) associated with HWA imidacloprid treatment areas. Thirty stream locations were sampled in GRSM to assess the presence and concentration of imidacloprid, 5-hydroxy, and olefin. Water samples were collected from 10 streams downstream from riparian areas where hemlocks received imidacloprid soil treatments and immediately upstream from hemlock treatment areas in each of the selected 10 streams. In addition, water samples were collected from 10 control streams each in close proximity to one of the 10 streams flowing through treatment areas.

We know astonishingly little about the human health effects of neonicotinoids

Neonicotinoids—the world’s most widely used and fastest growing type of insecticide—have been at the center of the conversation about bee die-offs for several years. Even the U.S. Environmental Protection Agency (EPA) recently acknowledged that very small quantities can impact pollinators. But what about human health? “There is an amazing lack of information for such widely used pesticides,” Mount Sinai professor of pediatrics and preventative medicine and dean for global health Philip Landrigan told Civil Eats. Now, a number of scientists, including those at the U.S. National Toxicology Program, say a closer look is needed.

Thiacloprid, imidacloprid, and clothianidin affect the immunocompetence of honey bees

We investigated the sublethal effects of the neonicotinoids thiacloprid, imidacloprid, and clothianidin on individual immunity, by studying three major aspects of immunocompetence in worker bees: total hemocyte number, encapsulation response, and antimicrobial activity of the hemolymph. In laboratory experiments, we found a strong impact of all three neonicotinoids. Thiacloprid (24 h oral exposure, 200 microg/l or 2000 microg/l) and imidacloprid (1 microg/l or 10 microg/l) reduced hemocyte density, encapsulation response, and antimicrobial activity even at field realistic concentrations. Clothianidin had an effect on these immune parameters only at higher than field realistic concentrations (50–200 microg/l). These results suggest that neonicotinoids affect the individual immunocompetence of honey bees, possibly leading to an impaired disease resistance capacity.

Exposure to Pesticides Is A Risk Factor For Attention Deficit Hyperactivity Disorder (ADHD)

A commonly used pesticide may alter the development of the brain's dopamine system -- responsible for emotional expression and cognitive function -- and increase the risk of attention deficit hyperactivity disorder in children, according to a new Rutgers study. The research published Wednesday in the Journal of the Federation of American Societies for Experimental Biology (FASEB), by Rutgers scientists and colleagues from Emory University, the University of Rochester Medical Center, and Wake Forest University discovered that mice exposed to the pyrethroid pesticide deltamethrin in utero and through lactation exhibited several features of ADHD, including dysfunctional dopamine signaling in the brain, hyperactivity, working memory, attention deficits and impulsive-like behavior. These findings provide strong evidence, using data from animal models and humans, that exposure to pyrethroid pesticides, including deltamethrin, may be a risk factor for ADHD, says lead author Jason Richardson, associate professor in the Department and Environmental and Occupational Medicine at Rutgers Robert Wood Johnson Medical School and a member of the Environmental and Occupational Health Sciences Institute (EOHSI). "Although we can't change genetic susceptibility to ADHD, there may be modifiable environmental factors, including exposures to pesticides that we should be examining in more detail," says Richardson.

Are Bee Diseases Linked to Pesticides? — A Brief Review of Immune Suppression by Neonicotinoid Insecticides

Outbreaks of infectious diseases in honey bees, fish, amphibians, bats and birds in the past two decades have coincided with the increasing use of systemic insecticides, notably the neonicotinoids and fipronil. A link between insecticides and such diseases is hypothesised. Firstly, the disease outbreaks started in countries and regions where systemic insecticides were used for the first time, and later they spread to other countries. Secondly, recent evidence of immune suppression in bees and fish caused by neonicotinoids has provided an important clue to understand the sub-lethal impact of these insecticides not only on these organisms, but probably on other wildlife affected by emerging infectious diseases. The negative impacts of pesticides, in particular insecticides, on bees and other pollinators have never been disputed. Insecticides can directly kill these vital insects, whereas herbicides reduce the diversity of their food resources, thus indirectly affecting their survival and reproduction. At sub-lethal level (bLD50), neurotoxic insecticide molecules are known to influence the cognitive abilities of bees, impairing their performance and ultimately impacting on the viability of the colonies. In addition, widespread systemic insecticides appear to have introduced indirect side effects on both honey bees and wild bumblebees, by deeply affecting their health. Immune suppression of the natural defences by neonicotinoid and phenyl-pyrazole (fipronil) insecticides opens the way to parasite infections and viral diseases, fostering their spread among individuals and among bee colonies at higher rates than under conditions of no exposure to such insecticides. This causal link between diseases and/or parasites in bees and neonicotinoids and other pesticides has eluded researchers for years because both factors are concurrent: while the former are the immediate cause of colony collapses and bee declines, the latter are a key factor contributing to the increasing negative impact of parasitic infections observed in bees in recent decades.

Metabolomics to Explore Imidacloprid-Induced Toxicity in the Central Nervous System of the Freshwater Snail Lymnaea stagnalis

Metabolomics was applied to investigate imidacloprid induced sublethal toxicity in the central nervous system of the freshwater snail Lymnaea stagnalis. The snails (n = 10 snails) were exposed for 10 days to increasing imidacloprid concentrations (0.1, 1, 10, and 100 μg/L). The comparison between control and exposure groups highlighted the involvement and perturbation of many biological pathways. The levels of several metabolites belonging to different metabolite classes were significantly changed by imidacloprid exposure. A change in the amino acids and nucleotide metabolites like tryptophan, proline, phenylalanine, uridine, and guanosine was found. Many fatty acids were down-regulated, and the levels of the polyamines, spermidine and putrescine, were found to be increased which is an indication of neuron cell injury. A turnover increase between choline and acetylcholine led us to hypothesize an increase in cholinergic gene expression to overcome imidacloprid binding to the nicotinic acetylcholine receptors. Metabolomics revealed imidacloprid induced metabolic changes at low and environmentally relevant concentration in a nontarget species and generated a novel mechanistic hypothesis.

Sublethal Effect of Imidacloprid on Solenopsis invicta (Hymenoptera: Formicidae) Feeding, Digging, and Foraging Behavior

In this study, we exposed red imported fire ants, Solenopsis invicta Buren, to sublethal dosages of dietary imidacloprid and investigated its effect on ant feeding, digging, and foraging behavior. S. invicta consumed significantly more sugar water containing 0.01 microgram/ml imidacloprid than untreated sugar water. Ants fed with 0.01 microgram/ml imidacloprid also showed significantly increased digging activity than ants fed with untreated sugar water. However, imidacloprid at  0.25 microgram/ml significantly suppressed sugar water consumption, digging, and foraging behavior. These results indicate that imidacloprid at sublethal concentrations may have a significant and complicated effect on S. invicta.

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