How pesticides (neonicotinoids) change navigation, recruitment, and learning behavior of bees

Navigation in honeybees is studied with the help of a special radar that allows to trace the flights of individual bees over kilometers. In a typical experiment, the bees were trained to a feeder or they follow a dancing bee. Then we equipped one bee with a radar transponder and released it at a site within the range of the explored area. First, the animal performs a straight flight that would have brought it back from the feeder to the hive (vector flight) would it not have been transported to a different site. In the case of the dance follower, the bee performs the vector information transmitted in the dance, as described by Karl von Frisch and followers. Then the bee loops around (search flight), followed by a straight return flight to the hive (homing flight). We carried out the experiments in an area where the skyline of the horizon or a beacon at the hive did not guide the bees’ navigation. Thus, the bees referred only to the pattern of landmarks on the ground. We show that the memory structure used by the bees can be best conceptualized as a cognitive map storing the geometric relations of landmarks and important locations. Sublethal doses of neonicotinoids interfere selectively with the homing flight component based on this cognitive map memory, reducing the probability of successful returns to the hive. Chronic exposure to the neonicotinoid Thiacloprid reduces the attractiveness of a feeding site and the rate of recruitment.

Neonicotinoid-Contaminated Puddles of Water Represent a Risk of Intoxication for Honey Bees

In recent years, populations of honey bees and other pollinators have been reported to be in decline worldwide. A number of stressors have been identified as potential contributing factors, including the extensive prophylactic use of neonicotinoid insecticides, which are highly toxic to bees, in agriculture. While multiple routes of exposure to these systemic insecticides have been documented for honey bees, contamination from puddle water has not been investigated. In this study, we used a multi-residue method based on LC-MS/MS to analyze samples of puddle water taken in the field during the planting of treated corn and one month later. If honey bees were to collect and drink water from these puddles, our results showed that they would be exposed to various agricultural pesticides. All water samples collected from corn fields were contaminated with at least one neonicotinoid compound, although most contained more than one systemic insecticide. Concentrations of neonicotinoids were higher in early spring, indicating that emission and drifting of contaminated dust during sowing raises contamination levels of puddles. Although the overall average acute risk of drinking water from puddles was relatively low, concentrations of neonicotinoids ranged from 0.01 to 63 µg/L and were sufficient to potentially elicit a wide array of sublethal effects in individuals and colony alike. Our results also suggest that risk assessment of honey bee water resources underestimates the foragers' exposure and consequently miscalculates the risk. In fact, our data shows that honey bees and native pollinators are facing unprecedented cumulative exposure to these insecticides from combined residues in pollen, nectar and water. These findings not only document the impact of this route of exposure for honey bees, they also have implications for the cultivation of a wide variety of crops for which the extensive use of neonicotinoids is currently promoted.

An Overview Comparing Results from Two Decades of Monitoring for Pesticides in the Nation’s Streams and Rivers, 1992–2001 and 2002–2011

This report provides an overview of the U.S. Geological Survey National Water-Quality Assessment program and National Stream Quality Accounting Network findings for pesticide occurrence in U.S. streams and rivers during 2002–11 and compares them to findings for the previous decade (1992–2001). In addition, pesticide stream concentrations were compared to Human Health Benchmarks (HHBs) and chronic Aquatic Life Benchmarks (ALBs). The comparisons between the decades were intended to be simple and descriptive. Trends over time are being evaluated separately in a series of studies involving rigorous trend analysis. During both decades, one or more pesticides or pesticide degradates were detected more than 90 percent of the time in streams across all types of land uses. For individual pesticides during 2002–11, atrazine (and degradate, deethylatrazine), carbaryl, fipronil (and degradates), metolachlor, prometon, and simazine were detected in streams more than 50 percent of the time. In contrast, alachlor, chlorpyrifos, cyanazine, diazinon, EPTC, Dacthal, and tebuthiuron were detected less frequently in streams during the second decade than during the first decade.

Pesticides in U.S. Streams and Rivers: Occurrence and Trends during 1992–2011

During the 20 years from 1992 to 2011, pesticides were found at concentrations that exceeded aquatic-life benchmarks in many rivers and streams that drain agricultural, urban, and mixed-land use watersheds. Overall, the proportions of assessed streams with one or more pesticides that exceeded an aquatic-life benchmark were very similar between the two decades for agricultural (69% during 1992−2001 compared to 61% during 2002−2011) and mixed-land-use streams (45% compared to 46%). Urban streams, in contrast, increased from 53% during 1992−2011 to 90% during 2002−2011, largely because of fipronil and dichlorvos. The potential for adverse effects on aquatic life is likely greater than these results indicate because potentially important pesticide compounds were not included in the assessment. Human-health benchmarks were much less frequently exceeded, and during 2002−2011, only one agricultural stream and no urban or mixed-land-use streams exceeded human-health benchmarks for any of the measured pesticides. Widespread trends in pesticide concentrations, some downward and some upward, occurred in response to shifts in use patterns primarily driven by regulatory changes and introductions of new pesticides.

Finnish water fowl populations plummet

The populations of most types of Finnish water fowl have been declining steadily and aggressively for many years, a new study shows. The results of the study, conducted by the Finnish Game and Fisheries Research Institute (RKTL) and the Finnish Museum of Natural History, were published in the European Journal of Wildlife Research. Species of water bird whose numbers are swiftly dwindling include the widgeon (Anas penelope), the northern pintail (Anas acuta), the garganey (Anas querquedula), the tufted duck (Aythya fuligula), the pochard (Aythya ferina) and the coot (Fulica atra). Researchers say the drops are due to changes in the birds’ habitat; feeding becomes difficult for water fowl in hypertrophic or polluted waters. The research centre calls the population depletion a ”mystery,” since extra nutrients in the waters should make it easier for birds to feed. Shifts in the food chain may also affect the nutritional intake of young fowls, and small mammalian predators or other birds can eat the young of other species or destroy their nests.

Neonicotinoid insecticide travels through a soil food chain, disrupting biological control of non-target pests and decreasing soya bean yield

Neonicotinoids are the most widely used insecticides world-wide, but their fate in the environment remains unclear, as does their potential to influence non-target species and the roles they play in agroecosystems. We investigated in laboratory and field studies the influence of the neonicotinoid thiamethoxam, applied as a coating to soya bean seeds, on interactions among soya beans, non-target molluscan herbivores and their insect predators. In the laboratory, the pest slug Deroceras reticulatum was unaffected by thiamethoxam, but transmitted the toxin to predaceous beetles (Chlaenius tricolor), impairing or killing >60%. In the field, thiamethoxam-based seed treatments depressed activity–density of arthropod predators, thereby relaxing predation of slugs and reducing soya bean densities by 19% and yield by 5%. Neonicotinoid residue analyses revealed that insecticide concentrations declined through the food chain, but levels in field-collected slugs (up to 500 ng g−1) were still high enough to harm insect predators. Our findings reveal a previously unconsidered ecological pathway through which neonicotinoid use can unintentionally reduce biological control and crop yield. Trophic transfer of neonicotinoids challenges the notion that seed-applied toxins precisely target herbivorous pests and highlights the need to consider predatory arthropods and soil communities in neonicotinoid risk assessment and stewardship.

A multi-year field study to evaluate the environmental fate and agronomic effects of insecticide mixtures

A mixture of insecticides used in corn production was monitored over a three-year period in a field study to determine how long each persists in the environment, where each insecticide travels within the corn field, and the efficacy of using soil-applied insecticides with genetically modified corn. The genetically modified corn contained the insecticidal Cry1Ab and Cry3Bb1 proteins (Bt corn) and the Cry1Ab protein was found to persist only during the corn growing season in soil, runoffwater, and runoff sediment with highest concentrations measured during pollination. Very low concentrations of Cry1Ab proteins were measured in soil collected in the non-Bt corn field, and no Cry1Ab proteins were detected in shallow groundwater or soil pore water. Clothianidin, a neonicotinoid insecticide used as a seed coating, was detected in all matrices and remained persistent throughout the year in soil pore water. Tefluthrin, a pyrethroid insecticide applied at planting to control corn rootworm larvae (Diabrotica spp., Coleoptera: Chrysomelidae) populations, was consistently detected in soil, runoff water, and runoff sediment during the corn growing season, but was not detected in groundwater or soil pore water. Tefluthrin did not have an effect on root damage from corn rootworm larvae feeding to Bt corn, but did prevent damage to non-Bt corn. A slight reduction in grain yield was observed in the non-Bt, no tefluthrin treatment when compared to all other treatments, but no significant difference in grain yield was observed among Bt corn treatments regardless of soil insecticide application. In the current study, the use of tefluthrin on Bt corn did not significantly affect crop damage or yield, and tefluthrin may travel off-site in runoff water and sediment.

100+ Scientists Call on Obama’s Bee Task Force to Take Action on Pesticides

In a letter submitted for today’s White House “listening sessions” deadline, over 100 scientists from diverse disciplines (including Dutch toxicologist Henk Tennekes) cited the growing body of evidence that neonicotinoids and other systemic pesticides harm bees. These scientists called on leaders of President Barack Obama’s Pollinator Health Task Force to take action on pesticides to protect and promote healthy populations of bees and other pollinators.

Freshwater species have suffered a 76 per cent decline since 1970, an average loss almost double that of land and marine species

According to the Living Planet Report report, populations of fish, birds, mammals, amphibians and reptiles have declined by 52 per cent since 1970. Freshwater species have suffered a 76 per cent decline, an average loss almost double that of land and marine species. “Biodiversity is a crucial part of the systems that sustain life on Earth – and the barometer of what we are doing to this planet, our only home. We urgently need bold global action in all sectors of society to build a more sustainable future,” said WWF International Director General Marco Lambertini. Biodiversity declines in Africa highlight the intense pressure felt by tropical species. For the thousands of species tracked by the report, the tropics showed a 56 per cent loss across populations compared to 36 per cent in temperate zones. “The unique nature and natural resources of Africa are under more pressure than ever before. Life-sustaining ecosystems are rapidly degrading, thus compromising the future security, health and well-being of millions of African people, with the poor heavily and disproportionately bearing the brunt of these losses,” said Fred Kumah, Director of Africa at WWF International.

The world’s reptiles — turtles, snakes, lizards, alligators and crocodiles — are in trouble

The International Union for Conservation of Nature, which publishes an annual global roster of threatened and endangered species called the Red List, considers some 664 species of reptiles — representing more than 20 percent of known reptile species worldwide — as endangered or facing extinction. Meanwhile, the U.S. Fish & Wildlife Service considers about 10 percent of American reptiles threatened or endangered. The non-profit Center for Biological Diversity (CBD) considers reptiles “amazing creatures” with clever adaptations that have helped them survive for millions of years. CBD also points out that reptiles are valuable indicators of wider ecological health. “Because many reptile species are long-lived and relatively slow-moving, they suffer from disturbances like habitat loss or pollution for extended periods,” the group reports, adding that a diverse community of reptiles living in a given area is evidence of a healthy ecosystem that can support the plant and animal life they and other species need for food and cover.

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