Researchers find neonicotinoids present a danger to pollinators

AUGUST 8, 2019 REPORT

by Bob Yirka , Phys.org

A small team of environmentalists with Friends of the Earth, Toxicology Research International and Pesticide Research Institute has carried out a study of insecticide toxicity loading of chemical pesticides that are used on agricultural lands in the U.S. They have concluded that neonicotinoids present a major danger to pollinating insects and have posted their results on the open-access site PLOS ONE.

In the study (funded by Friends of the Earth), the group looked at the impact of the increased use of neonicotinoids on farming products in the U.S. They note that use of such insecticides has increased dramatically in the past 20 years.

Neonicotinoids are a class of insecticides that target the nervous systems of insects—they are both less expensive to make and less toxic to humans than other products, making them an appealing option for agriculture applications. The researchers note that they are far more toxic to insects, including those not targeted by agricultural practices than prior industrial insecticides. They also last a lot longer in the soil and are water-soluble, which means they travel from the soil to the water table when it rains.

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Lizards, mice, bats and other vertebrates are important pollinators, too

Study reviews the global importance of vertebrate pollinators for plant reproduction

Date:  April 4, 2018

Source:  Ecological Society of America

Bees are not the only animals that carry pollen from flower to flower. Species with backbones, among them bats, birds, mice, and even lizards, also serve as pollinators. Although less familiar as flower visitors than insect pollinators, vertebrate pollinators are more likely to have co-evolved tight relationships of high value to the plants they service, supplying essential reproductive aid for which few or no other species may substitute.

In plants known to receive flower visitations from vertebrates, fruit and seed production drops 63 percent, on average, when the larger animals, but not insects, are experimentally blocked from accessing the plants, ecologists report in the March cover study for the Ecological Society of America's journal Frontiers in Ecology and the Environment.

Fabrizia Ratto and colleagues reviewed 126 such animal exclusion experiments to get an idea of how dependent wild plants are on animals with backbones for reproduction. The researchers selected published studies that quantified pollination through the subsequent growth of fruit or seeds.

Read on  

Pollinator extinctions alter structure of ecological networks

June 21, 2017 by Carol Clark

The absence of a single dominant bumblebee species from an ecosystem disrupts foraging patterns among a broad range of remaining pollinators in the system—from other bees to butterflies, beetles and more, field experiments show.

Biology Letters published the research, which may have implications for the survival of both rare wild plants and major food crops as many pollinator species are in decline.

"We see an ecological cascade of effects across the whole pollinator community, fundamentally changing the structure of plant-pollinator interaction networks," says Berry Brosi, a biologist at Emory University and lead author of the study. "We can see this shift in who visits which plant even in pollinators that are not closely related to the bumblebee species that we remove from the system."

If a single, dominant species of bumblebee mainly visits an alpine sunflower, for instance, other pollinators—including other species of bumblebees—are less likely to visit alpine sunflowers. If the dominant bumblebee is removed, however, the dynamic changes.

"When the sunflowers became less crowded and more available, a broader range of pollinators chose to visit them," Brosi says.

The field experiments, based in the Colorado Rockies, also showed that the removal of a dominant bumblebee species led to fewer plant species being visited on average. "That was a surprise," Brosi says. "If a nectar resource is abundant and highly rewarding, more types of pollinators will go for it, leaving out some of the rarer plants that some of the other pollinator species normally specialize in."

The findings are important since most flowering plants and food crops need pollinators to produce seeds.

"Basically, for almost every pollinator group that we have good data for, we've seen declines in those pollinators," Brosi says. "The results of our field experiments suggest that losses of pollinator species—at a local population level or on a global, true extinction scale—are likely to have bigger impacts on plant populations than previously predicted by simulation models."

The experiments were done at the Rocky Mountain Biological Laboratory near Crested Butte, Colorado. Located at 9,500 feet, the facility's subalpine meadows are too high for honeybees, but they are filled with a variety of bumblebees and other pollinators.

Read more at: 

Just What Makes That Little Old Ant… Change a Flower's Nectar Content?

Apr. 24, 2013 — Ants play a variety of important roles in many ecosystems. As frequent visitors to flowers, they can benefit plants in their role as pollinators when they forage on sugar-rich nectar. However, a new study reveals that this mutualistic relationship may actually have some hidden costs. By transmitting sugar-eating yeasts to the nectar on which they feed, ants may be indirectly altering the nectar-chemistry and thus affecting subsequent pollinator visitations. 

Many species of plants benefit from interacting with ants, and some even secrete special sugary substances to attract ants. Plants produce sugar, in the form of nectar, and in exchange ants provide services such as pollination or protection from herbivores. 

The main components of nectar that attract pollinators include three dominant sugars -- sucrose, fructose, and glucose -- and amino acids (or proteins). The chemical composition of nectar differs among plant species and has been thought to be a conservative trait linked to pollinator type. For example, plants pollinated by hummingbirds tend to have nectar with high amounts of sucrose. In addition, nectar composition is thought to be regulated by the plant. 

"When people think about how flowers are pollinated, they probably think about bees," notes Clara de Vega, a postdoctoral researcher at the Estación Biológica de Doñana, Spain. "But ants also pollinate flowers, and I am interested in the role ants play in pollination since it is still poorly understood." 

Continued: http://www.sciencedaily.com/releases/2013/04/130424185232.htm

New report from European Food Safety Authority deems neonicotinoid insecticides as a high risk to honeybees

Wild pollinators such as bumblebees and moths contribute about 90% of UK insect pollination, which is worth £510 million to British farmers.

Buglife welcomes new report establishing neonicotinoid insecticides as high risk to bees

January 2013. Wildlife charity, Buglife - The Invertebrate Conservation Trust has welcomed a report released by the European Food Safety Authority (EFSA) that deems neonicotinoid insecticides as a high risk to honeybees and also highlights the gaps in research on how neonicotinoids might affect other pollinators such as bumblebees.

EFSA's scientists have evaluated the risks that bees face from the insecticides Clothianidin, Imidacloprid and Thiamethoxam. The report concludes that "only uses on crops not attractive to honeybees were considered acceptable" because of exposure through nectar and pollen.

Honeybees at high risk from neonicotinoids dust
The EFSA also found that honeybees were at a high risk from neonicotinoids dust clouds created by drilling treated seeds into the ground and from guttation fluid (water sweated out by leaves and ingested by insects); risks which are not normally assessed when regulating pesticides. In addition, the EFSA report also identified ‘limited information' about the risk posed by neonicotinoids to populations of wild pollinators such as bumblebees.

In September 2012 Defra produced a report that stated that ‘no change in the existing regulation of Neonicotinoids is required'.

Matt Shardlow, Buglife CEO said "Buglife has been asking the Department for Environment, Food and Rural Affairs (Defra) to follow the correct legal process, apply the precautionary principle and suspend all neonicotinoid insecticides immediately. We hope that these important findings will spur Defra into taking action".

Read more: http://www.wildlifeextra.com/go/news/neonicotinoid-insecticides.html