Archive for the ‘pollinators’ Category

From PestNet

FEBRUARY 17, 2021

Neonicotinoid pesticide residues found in Irish honey

by Thomas Deane, Trinity College Dublin

Credit: CC0 Public Domain

Researchers from Trinity and Dublin City University found that Irish honey contained residues of neonicotinoid insecticides.

Neonicotinoids are the most widely used group of insecticides globally, used in plant protection products to control harmful insects.

Neonicotinoids are systemic pesticides. Unlike contact pesticides, which remain on the surface of the treated parts of plants (e.g. leaves), systemic pesticides are taken up by the plant and transported throughout its leaves, flowers, roots and stems, as well as incorporated into pollen and nectar.

In the European Union, their use is now restricted due to concerns about risks to bees and other non-target organisms. At the time of sampling for this study, their use was still approved in Ireland for certain agricultural crops.

Key findings

  • Of 30 honey samples tested, 70% contained at least one neonicotinoid compound
  • Almost half (48%) the samples contained at least two neonicotinoids
  • Exposure to pesticides does not just occur in agricultural settings
  • This research for the first time has identified the presence of clothianidin, imidacloprid and thiacloprid in Irish honey from a range of hive sites across a range of land use types
  • The proportion and concentration of neonicotinoids in honeys from both agricultural and urban habitats, compared with semi-natural or other land covers, suggests that exposure of bees to neonicotinoids can potentially occur in a variety of environments

Residue levels were below the admissible limits for human consumption according to current EU regulations, and thus pose no risk to human health.

However, the average concentration of one compound (imidacloprid) was higher than concentrations that have been shown in other studies to induce negative effects on honey and bumble bees.

Dr. Saorla Kavanagh, lead author on the study, currently working at the National Biodiversity Data Centre, said: “Given that these compounds have been shown to have adverse effects on honey bees, wild bees, and other organisms, their detection in honey is of concern, and potential contamination routes should be explored further.”

Professor Jane Stout, from Trinity’s School of Natural Sciences, said: “These results suggest that bees and other beneficial insects are at risk of exposure to contaminants in their food across a range of managed habitats—not just in agricultural settings. And even though we found residues at low concentrations, prolonged exposure to sublethal levels of toxins can cause effects that are still not fully understood by scientists or regulators. Therefore, we shouldn’t relax restrictions on their use.”

Dr. Blánaid White, DCU, said: “Our findings are consistent with others from outside Ireland, and neonicotinoids unfortunately seem to be ubiquitous in honeys worldwide. It’s reassuring that residues do not exceed safe levels, but it is an important warning that neonicotinoids should not be reintroduced into Irish environments, as they could potentially cause health or environmental concerns.”

Explore furtherOn balance, some neonicotinoid pesticides could benefit bees: study

Provided by Trinity College Dublin

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The Role of Niche Complementarity in Pollinator Agricultural Management and Crop Production

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Agrilinks Team

Nov 30, 2020

photograph of pollinator
Photo Credit: Ersin Aslan

This post is written by Katie James, PhD Research Student, Natural Resources Institute, University of Greenwich, U.K.

The role of pollinator diversity in crop production

Pollinators play an integral role in crop production within agricultural landscapes due to the part they play in ensuring crop plant sexual reproduction by the transfer of pollen between crops. Studies have shown that greater diversity in pollinator networks results in crops that have higher yields, as well as fewer malformations (Blitzer et al., 2012) which can make the crop undesirable for commercial use due to a lower marketable quality. But the mechanisms within species diversity which facilitate greater yield and fewer malformations are not fully understood. The few studies that have explored the interrelationships between pollinator guilds on crop production and nutritional composition have shown that open-pollinated crops have a higher fat and vitamin E content (Brittain et al., 2014), and are of a better economic quality due to higher weight, fewer malformations and higher graded quality fruits compared to single species or hand-pollinated crops (Abrol et al., 2019). Additionally, it has been shown that wild bees provide not only an economic benefit from higher quality yields but also better shelf life and lower sugar-acid ratios, allowing for better storability of fruit crops (Klatt et al., 2014).

The role of complementarity between pollinators

Previous research has shown that plant visitation from multiple pollinator species produces fruits at a greater economic rate, with higher marketability (Albano et al., 2009). This is attributed mainly to the varying morphologies, behavioral traits and visitation rates of differing pollinator species. The overlap between these traits and behaviors (also known as niche complementarity) is thought to be why a greater diversity of pollinators provides a higher quality, yield and marketable quality. Niche complementarity between pollinator communities can be exhibited across multiple scales including spatial, temporal, seasonally and diurnally (Brittain et al., 2014; Garibaldi et al., 2016Rader et al., 2013). The concept of niche complementarity, as well as promoting pollinator diversity, acts as a buffer to reduce the loss of pollination services due to species decline (Blüthgen et al., 2011Inouye et al., 2015Mallinger et al., 2014).

This overlap between species behavior and visitation is especially valuable in monoculture crops which produce flowers repeatedly over a season (such as strawberry). In high diversity pollinator communities, there will be more variation among pollinator species in their seasonality, thus ensuring more flowers are pollinated, which produces higher yields throughout the growing season whilst enhancing the mutualistic relationship between species, rather than competition for available resources (Grab et al., 2017). Additionally, the size of pollinators and how hairy they are also plays a key role in the effectiveness of a pollinator. Larger bee species, such as Xylocopa sp., which can collect large pollen loads and encounter a larger surface area of the flower, lead to a higher rate of pollination in single-flower visit (Mensah et al., 2011). Pollinators have been shown to visit different levels of floral canopy, possess different approaches to each flower and visit at varying times of the day. In apple orchards, bumblebees prefer the top canopy and tend to approach the flower from above, whereas hoverflies and wild bees prefer the lower canopy; thus, the combination of pollinator guilds provides a level of complementarity on smaller scales, as well as across a region. Species also vary in foraging behavior during the day, with foraging most frequent in the early morning and later afternoon in bees, and secondary pollinators in the morning and midday (Miñarro et al., 2018). Consequently, when considering the future of pollinator management, investigation is required to establish community-level management schemes to account for the role and importance of complementarity and how the interactions between species can be utilized to promote higher yields, quality, and if there is a direct relationship with micronutrient composition.

Future development and project aim

Most global crops that are rich in micronutrients are also pollinator dependent. Micronutrient deficiencies are expected to become more severe in the next 20-30 years due to several interrelated factors, including climate change and a growing human population that is expected to place increasing stress on food supply and production (Bongaarts, 2019). These pressures are likely to be most prominent in areas where micronutrient deficiency is already an issue and especially in developing countries (Eilers et al., 2011). Currently, micronutrient deficiencies are three times more probable in regions of high pollinator dependency for vitamin A and iron (Chaplin-Kramer et al., 2014). If pollinator populations and biodiversity continue to decline, this will induce negative impacts on nutrient availability, and ultimately human health. Therefore, there is a demand for research to find sustainable and non-intensive ways to promote micronutrient-rich food production by way of pollinator promotion, protection and integration within environmental management strategies. Over the next few years, this project aims to examine the relationships between different pollinators and establish the mechanisms which facilitate yield, quality, and micronutrient content of fruit and vegetable crops. It is hoped that this will inform the development and integration of sustainable agricultural management strategies and improve crop production in terms of micronutrient availability and economic enhancement.

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Buzzing activity around pollinator health

By Anu Veijalainen, CABI. Reblogged from CABI Hand-picked blog.

Yesterday I cherished the start of spring in England by attending an event devoted to pollinators and pollination at the University of Reading. Most presentations at this meeting organised by the Royal Entomological Society were understandably about bees, but we also heard a few talks highlighting the importance of other pollinator groups.

For about five years now the media has been broadcasting alarming news about declining bee populations especially in Europe and North America. While the amounting evidence points to neonicotinoid insecticides being a major cause for the decline, I learnt yesterday that the situation is actually rather complex, other stressors are also involved, and scientists are still eagerly trying to form a complete understanding of the issue.

European Honey Bee Touching Down
Photo by Autan, under Creative Commons BY-NC-ND 2.0 license

Multiple stressors threaten bee populations

The mysterious decline of bee populations has granted these insects a lot of press exposure in recent years – and rightly so; after all, pollinators provide a crucial ecosystem service. However, in the midst of following this growing information load, I realised that it was hard to keep up with the prevailing scientific consensus on the matter, especially on neonicotinoids. Therefore, I was glad to see that a review article summarising the current scientific evidence concerning the effects of neonicotinoid insecticides on insect pollinators intended to assist political decision-making was published at the end of last year. Another interesting review focusing on neonicotinoids and the prevalence of parasites and disease in bees came out earlier this month. Both reviews list a substantial number of recent studies indicating a connection between bee deaths and neonicotinoids.

New scientific case studies on bee health continue being published on a regular basis, and political and public discussion around bees and other pollinators remains active. This is demonstrated by searching for new records added to the CAB Abstracts database in the first four months of this year: using the searchstring ‘pollinator AND population AND decline‘ returns 25 results. Furthermore, last month the European Food Safety Authority (EFSA) launched a new website dedicated to bee health called #Efsa4Bees – Parasites, pathogens and pesticides: making sense of multiple stressors.

In conclusion, keeping up-to-date with the advancements in the field is challenging because there is a large amount of new information being produced and the studies have found somewhat conflicting results, i.e., indicating that bees are in decline due to a number of factors including pesticides, habitat loss and diseases. All these topics were also covered in the presentations given yesterday at the meeting ‘Progress in pollination and pollinator research’.

Potential for a brighter future 

Being concerned about the current state of bee and other pollinator populations, I felt a sense of relief entering the lecture hall yesterday and noticing that so many people – over 80 mainly UK-based scientists attending this one-day event – have dedicated their careers to understanding and conserving pollinators. A number of the studies presented at the event had investigated how diverse bee communities can be supported in different landscapes, reflecting the fact that pollinators are also threatened by agricultural intensification and other human-induced land use changes. My day, however, culminated towards the end of the last session when excellent talks were given on the effects of insecticides on bees.

In her expert presentation, Dr Linda Field of Rothamsted Research first explained why neonicotinoids had become such efficient and commonly used insecticides in agriculture. She then moved on to state that in her opinion, blaming neonicotinoids for bee population declines was fairly “easy” (compared to, e.g., diseases and adverse weather events) yet hard to prove, and closed the talk by expressing what she thought was needed of pest management in the future. She highlighted the encouraging progress made in two areas of research: first, understanding how insecticides interact with target proteins and the variation of these proteins in different insects, and second, how insecticides are detoxified by insects and the variation of these mechanisms in different insects.

According to Dr Field, future pest management strategies should apply, for example, biological and cultural control, pest-resistant crop plants, and pesticides that specifically affect target pests but are not harmful for beneficial organisms.

Further activities for the concerned and the curious

If you’re interested in finding out more about the role of neonicotinoids in bee deaths, the AgriSciences group of the Society of Chemical Industry (SCI) is organising a topical one-day event titled ‘Are neonicotinoids killing bees?’ in London this September. Registration is now open.

Finally, I’d like to share a list of links to relevant news articles and scientific papers I’ve encountered in the last a couple of months. They represent only a handful of the articles out there, but demonstrate the somewhat conflicting messages of studies and the active work scientists are conducting on pollinator health.


Godfray HCJ, Blacquière T, Field LM, Hails RS, Potts SG, Raine NE, Vanbergen AJ & McLean AR (2015) A restatement of recent advances in the natural science evidence base concerning neonicotinoid insecticides and insect pollinators. Proceedings of the Royal Society B 282: 20151821.

Sánchez-Bayoa F & Desneux N (2016) Neonicotinoids and the prevalence of parasites and disease in bees. Bee World 92: 34–40.

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Pesticides found in honey around the world


Insecticides are cropping up in honey samples from around the world, a new study finds, suggesting that bees and other pollinators are being widely exposed to these dangerous chemicals. The commonly used insecticides, known as neonicotinoids, are absorbed by plants and spread throughout their tissues. When pollinators collect and consume contaminated pollen and nectar, they can suffer from learning and memory problems that hamstring their ability to gather food and sometimes threaten the health of the whole hive. That’s a pressing concern because of the important role of honey bees and wild bees in pollinating crops, particularly fruits and vegetables. To get an idea of the extent of the threat to pollinators from pesticides, researchers in Switzerland asked their friends, relatives, and colleagues around the world to provide locally sourced honey. They found neonicotinoids most frequently in samples from North America, where 86% had one or more neonicotinoid, and least often in South America, where they occurred in 57% of samples. Globally, just over a third of samples had levels that have been shown to hurt bees, the researchers report today in Science. None of the samples had concentrations dangerous to human health. More than two types of neonicotinoids turned up in 45% of the honey samples, and 10% had four or five; the effects of mixtures are not known, but suspected to be worse. The team calls on governments to make more data available on the amounts of neonicotinoids being used in agriculture, which would help clarify the relationship between the amounts used by farmers and how much turns up in honey.

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Efforts benefit environment and economy

We have heard a lot in recent years about the plight of honey bees and how agriculture has done its part to contribute to declining populations of the bee family (Anthophila).

We have learned it is not just agricultural practices that have led to the serious decline in these beneficial pollinators; a host of other factors—things like disease and the decline in native plants that normally help the species survive and thrive in a healthy environment—have contributed as well .

Regardless of the cause of the overall decline, farmers, biologists and conservationists alike recognize the necessity of keeping honey bees healthy. Otherwise, the balance of our delicate eco-system is at risk. Since honey bees alone play such a critical role in pollination of various plants and crops, their decline across the globe poses a growing risk to global food production.

Agriculture must face the role it plays in the survival of honey bees, but the latest research indicates their health and ultimate survival as a species goes beyond a one-direction solution. Biologists are discovering that to address the needs of pollinators, every aspect of their health and survival must be examined.

Thanks to the work of an Arizona ethnobiologist and agroecologist, we are learning that not only honey bees, but all types of pollinators may be facing a similar crisis, and the far-ranging solution will require a broad spectrum of conservation support.


Gary Nabhan, a University of Arizona conservation biologist and the author of dozens of books on food, farming and biology, works with pollinators, including native bees, butterflies, hummingbirds, and even nectar-feeding bats along the Arizona-Mexico international border. His efforts represent ground-breaking research that not only promises to benefit at-risk bees, birds and other pollinator animals, but also offers insight into how pollinator conservation can positively affect the region’s economically-challenged human population.

It’s an out-of-the-box cross-cooperation concept that brings together farmers, landowners, conservationists, area residents, government officials and local high school students who have met in the middle of an arid desert region to find common solutions to a multitude of social, environmental and biological problems that mirror life in broader areas of the world, beyond state and international borders.

Nabhan is in a unique position and location to tackle such a complex project. With resources afforded by the university and complimented by The Nature Conservancy and the Audubon Society, Southern Arizona plays host to one of the most diverse populations of pollinators on the continent. Hundreds of pollinator species have made their home in the northwestern corner of the Madrean Archipelago, a region full of mountains and floodplains, a location noted for the highest diversity of native bees, birds and mammals anywhere in the lower 48 states.

The area is also home to nearly 50,000 residents, many of whom are economically challenged to make a living in an area that can be harsh and unforgiving. As a result, gainful employment is tough to come by and lifestyles are often simple and limited as a result.

Nabhan, recognizing that these many factors provide a rare opportunity for his research, created Borderlands Restoration, a recognized low-profit, limited liability company designed to tackle not only the problems of pollinators, but also the socio-economic concerns of the local human population.


His plan was multi-faceted. The company laid plans to assess and improve the natural pollinator habitat of the region by identifying the decline of native plant species that pollinators rely upon for survival, many of which had all but disappeared for various reasons, including the rise of commercial agriculture on both sides of the U.S.-Mexico border.

By rebuilding these missing elements in the local ecology, pollinators once again began to show signs of improvement. From volunteers to paid high school interns, existing and new nurseries were soon being established to promote the growth of native plants that pollinators prefer. These plants were then re-established on private and public land all across the region, especially in those areas where dense populations of pollinators were found, specifically along waterways and in the flood plains of low-lying areas.

Through his company, Nabhan also started working on erosion control and rainwater collection areas which increased soil moisture and stabilization, another component in helping to restore the ecology and natural habitat of pollinators in the region.

Ronald Pulliam, former science adviser for the U.S. Department of Interior and a Borderlands founder, says the efforts have created a restoration economy for the people of the area and at the same time is helping to rebuild pollinator populations.

The far-reaching advantages are many, including a supply of native perennials that can be planted surrounding the large number of new acres of alfalfa and cotton grown on both sides of the border.  Such practices can help offset the loss of native plants and resolve, or at least slow, the loss of pollinators subject to chemical exposure resulting from these agricultural operations.

From an economic standpoint, the project has already proven to be a major contributor to local families. The second-largest employer in remote Patagonia, Arizona, the company also utilizes seasonal workers and a robust number of volunteers who have taken an interest in conservation and the benefits it is providing local families. Supported by university educators, many local students have made commitments to continue their education through university and college programs, especially in fields related to conservation, ecology and biology.

The highlights and details of the work of Borderlands Restoration and innovator Gary Nabhan are currently highlighted in the November issue of the Scientific American, in a well-crafted article by writer Alexis Marie Adams. Traveling with Nabhan as he prosecuted his work across the region, Adams chronicled how the cooperation and dedication of a handful of men and women are helping to change the future of pollinators of the region, while giving hope for a better life to the people who are working to find solutions to major ecological challenges in Southern Arizona.

Read the article here.

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Study shows pollinators help Texas cotton producers

What is in this article?:

  • Diversity of pollinators improve cotton yield
  • Study conducted in South Texas

A diversity of pollinators, including honey bees but others, such as this butterfly, appear to be important for cotton production, according to a South Texas study.


According to the results of a new study published in the journal Agriculture, Ecosystems & Environment today (June 16, 2016 issue), South Texas cotton fields surrounded by natural land cover and an increase in the number of natural pollinators can result in an overall increase in cotton production – by as much as 18 percent.

Shalene Jha, assistant professor of integrative biology at the University of Texas-Austin and senior author of the study, says increasing the diversity of pollinator species around cotton fields—including bees, flies and butterflies—can dramatically increase yields. Using South Texas as a basis for the study, she concludes that annual cotton revenues of the region can be increased by more than $1.1 million.

“Texas produces about 25 percent of the nation’s cotton and South Texas produces about 15 percent of the state’s total. Cotton is the world’s most economically valuable nonfood crop,” Jha reports.

Increasing yields through diversified pollinator populations could prove to be a major boost to South Texas cotton production, and potentially for cotton producers across the state. According to the study, which focused only on South Texas cotton fields, pollinator populations and crop conditions vary widely across Texas. But the pollinator factor could prove beneficial for other areas of the state and beyond.

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