Archive for the ‘Honey bees’ Category

Farmers are overusing insecticide-coated seeds, with mounting harmful effects on nature

Published: February 22, 2022 8.41am EST


  1. John F. TookerProfessor of Entomology and Extension Specialist, Penn State

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John F. Tooker receives funding from the United States Department of Agriculture and the Pennsylvania Soybean Promotion Board.


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Planting season for corn and soybeans across the U.S. will begin as soon as March in Southern states and then move north. As farmers plant, they will deploy vast quantities of insecticides into the environment, without ever spraying a drop.

Almost every field corn seed planted this year in the United States will be coated with neonicotinoids, the most widely used class of insecticides in the world. So will seeds for about half of U.S. soybeans and nearly all cotton, along with other crops. By my estimate, based on acres planted in 2021, neonicotinoids will be deployed across at least 150 million acres of cropland – an area about the size of Texas.

Neonicotinoids, among the most effective insecticides ever developed, are able to kill insects at concentrations that often are just a few parts per billion. That’s equivalent to a pinch of salt in 10 tons of potato chips. Compared with older classes of insecticides, they appear to be relatively less toxic to vertebrates, especially mammals.

But over the past decade, scientists and conservation advocates have cited a growing body of evidence indicating that neonicotinoids are harmful to bees. Researchers also say these insecticides may affect wildlifeincluding birds that eat the coated seeds.

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In response to these concerns, Connecticut, Maryland, Vermont, Massachusetts, Maine and New Jersey have enacted laws limiting use of neonicotinoid insecticides. Other states are considering similar measures. Consumer and environmental advocates are also suing to force the U.S. Environmental Protection Agency to regulate coated seeds more tightly.

As an applied insect ecologist and extension specialist who works with farmers on pest control, I believe U.S. farmers are using these insecticides far more heavily than necessary, with mounting harm to ecosystems. Moreover, our ongoing research indicates that using farming strategies that foster beneficial, predatory insects can greatly decrease reliance on insecticides.https://cdn.knightlab.com/libs/juxtapose/latest/embed/index.html?uid=c74b20ca-8eb2-11ec-a554-13fc6baea232Use of imidacloprid, a common neonicotinoid, increased dramatically from 1994 to 2019 (move slider to compare years).

Insecticides on seeds

Most neonicotinoids in the U.S. are used as coatings on seeds for field crops like corn and soybeans. They protect against a relatively small suite of secondary insect pests – that is, not the main pests that typically damage crops. National companies or seed suppliers apply these coatings so that when farmers buy seeds they just have to plant them. As a result, surveys of farmers indicate that about 40% are unaware that insecticides are on their seeds.

The share of corn and soybean acreage planted with neonicotinoid-coated seeds has increased dramatically since 2004. From 2011 to 2014, the amount of neonicotinoids applied to corn doubled. Unfortunately, in 2015 the federal government stopped collecting data used to make these estimates.

Unlike most insecticides, neonicotinoids are water soluble. This means that when a seedling grows from a treated seed, its roots can absorb some of the insecticide that coated the seed. This can protect the seedling for a limited time from certain insects.

But only a small fraction of the insecticide applied to seeds actually enters seedlings. For example, corn seedlings take up only about 2%, and the insecticide persists in the plant for only two to three weeks. The critical question: Where does the rest go?

Treated and untreated seeds on a black background
Soybean seeds treated with neonicotinoids (dyed blue to alert users to the presence of pesticide) and treated corn seeds (dyed red) versus untreated seeds. Ian Grettenberger/PennState University, CC BY-ND

Pervading the environment

One answer is that leftover insecticide not taken up by plants can easily wash into nearby waterways. Neonicotinoids from seed coatings are now polluting streams and rivers across the U.S.

Studies show that neonicotinoids are poisoning and killing aquatic invertebrates that are vital food sources for fish, birds and other wildlife. Recent research has connected use of neonicotinoids with declines in the abundance and diversity of birds and the collapse of a commercial fishery in Japan.

Neonicotinoids also can strongly influence pest and predator populations in crop fields. In a 2015 study, colleagues and I found that use of coated soybean seeds reduced crop yields by poisoning insect predators that usually kill slugs, which cause serious damage in mid-Atlantic corn and soybeans fields. Subsequently, we found that neonicotinoids can decrease populations of insect predators in crop fields by 15% to 20%.

Recently we found that these insecticides can contaminate honeydew, a sugary fluid that aphids and other common sucking insects excrete when they feed on plant sap. Many beneficial insects, such as predators and parasitic wasps, feed on honeydew and may be poisoned or killed by neonicotinoids.

Slugs, shown here on a soybean plant, are unaffected by neonicotinoids but can transmit the insecticides to beetles that are important slug predators. Nick Sloff/Penn State UniversityCC BY-ND

Are neonicotinoids essential?

Neonicotinoid advocates point to reports – often funded by industry – that argue that these products provide value to field crop agriculture and farmers. However, these sources typically assume that insecticides of some type are needed on every acre of corn and soybeans. Therefore, their value calculations rest on comparing neonicotinoid seed coatings with the cost of other available insecticides.

Recent field studies, however, demonstrate that neonicotinoid-coated seeds provide limited insect control because target pest populations tend to be scarce and treating fields for them yields little benefit.

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Does this mean that the U.S. should follow the European Union’s lead and ban neonicotinoids or adopt strict limits like those enacted in New Jersey?

As I see it, neonicotinoids can provide good value in controlling critical pest species, particularly in vegetable and fruit production, and managing invasive species like the spotted lanternfly. However, I believe the time has come to rein in their use as seed coatings in field crops like corn and soybeans, where they are providing little benefit and where the scale of their use is causing the most critical environmental problems.


Instead, I believe agricultural companies should promote, and farmers should use, integrated pest management, a strategy for sustainable insect control that is based on using insecticides only when they are economically justified. Recent research at Penn State and elsewhere reaffirms that integrated pest management can control pests in corn and other crops without reducing harvests.

Concerns about neonicotinoid-coated seeds are mounting as research reveals more routes of exposure to beneficial animals and effects on creatures they are not designed to kill. Agricultural companies have done little to address these issues and seem more committed than ever to selling coated seeds. Farmers often have very limited choice if they want to plant uncoated seeds.

Scientists are sounding the alarm about rising extinction rates worldwide, and research indicates that neonicotinoids are contributing to insect declines and creating more toxic agricultural lands. I believe it’s time to consider regulatory options to curb the ongoing abuse of neonicotinoid-coated seeds.

This is an update of an article originally published on June 26, 2018.

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Research Finds Protecting Pollinators is Critical For Food Security in Africa

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Nov 06, 2020

Photo Credit: Aleksandra Georgieva

This post is written by Sunday Ekesi, Michael Lattorff, Thomas Dubois, International Centre of Insect Physiology and Ecology (ICIPE).


Pollination is crucial for food production, human livelihoods, and the preservation of biodiversity in natural ecosystems. Global crop production is highly dependent on pollinators. Approximately 75% of all crop plants are dependent on animal-mediated pollination and a recent analysis estimated the annual market value of pollinator services at US$235-577 billion. Thus, pollinators and the pollination services they provide serve a crucial function in food security. In many developing countries, agricultural production has become increasingly dependent on pollination services, as the relative number of pollination-dependent crops has increased three times compared to developed countries over the past 50 years. Pollination of crop plants by insects also contributes directly to human nutrition by increasing the availability of critical micronutrients. Animal-pollinated crops contain the majority of the available dietary lipid, vitamin A, C, and E, which are critical for the physical and intellectual development of children, as well as of key importance to other vulnerable groups including pregnant women, populations in disease risk regions (e.g. malaria endemic regions), and immuno-compromised individuals (due to malnutrition or pre-existing conditions). Beyond supporting crop production and human health through a diversified diet, pollinators are also a source of several commercial products (e.g., honey, wax, bee venom, royal jelly and resins) important for cosmetics, medicine, and cultural identity. Yet, despite their importance, pollinators are under increasing pressure and populations are declining worldwide.

Pollination R4D to improve food security: Examples from the International Centre of Insect Physiology & Ecology (ICIPE)

Assessing pollinator diversity

Globally, declines in insect pollinator populations (due to diverse factors including unsustainable agricultural practices, habitat destruction, and climate change) are threatening crop production amidst the growing demand for food driven by human population growth. To conserve and augment the population of pollinators for horticultural crops, we first need a basic understanding of their diversity. In this regard, we have undertaken surveys on avocado along the altitudinal gradient of the Eastern Afromontane region of Taita Hills, Kenya. Diverse pollinators belonging to 28 species in 14 families were observed visiting avocado. Overall, the proportion of honeybee (Apis mellifera) visits were the highest. In Murang’a, Kenya, a richer assembly of flower visitors was observed — including 73 species in 29 families. The most abundant families were ApidaeCalliphoridaeRhiniidae, and Syrphidae. Honeybees comprised 95.8% of Apidae. Other bee species included Braunsapis sp.Ceratina (Simioceratina) sp. (both Apidae), and Nomia sp., Lasioglossum sp., Pseudapis sp. (both Halictidae). On macadamia, stingless bee species from the genus Hypotrigona and Liotrigona have also been identified as efficient pollinators to enhance pollination and increase the productivity of the crop.

Understanding pollinator deficits and exploring opportunities to utilize pollinators to increase crop yields

Intensification of agriculture is leading to losses of wild pollinator species and hence of pollination services required to increase crop yields. As a result of the threats facing honeybees and other pollinators, ICIPE has been developing tools to utilize alternative managed pollinators (e.g., honeybees, stingless bees, and carpenter bees). In one of the major avocado growing areas of Kenya (Murang’a county), we analyzed the pollination deficit in avocado. This is the decrease in crop yield due to lack of sufficient pollination services. We found a 27% loss of fruits due to suboptimal pollination. However, supplementation of smallholder avocado farms with two honeybee colonies was sufficient to reverse this pollination deficit, increasing avocado yield by 180% and income by US$168 per farmer per season.

The domestication of stingless bees as alternative pollinators is a major component of activity at ICIPE. Through this activity, it has been possible to domesticate 14 species from East, West, and Central Africa; among which 6 have been widely evaluated and promoted with respect to their pollination efficiency. We are currently implementing activities for the use of stingless bee-targeted pollination on specific crops in open fields. In Kakamega, Kenya, research activities implemented jointly with smallholder farmers on pollination showed that stingless bee species, such as Hypotrigona gribodoi, are more efficient in improving green pepper fruit and seed quality in open fields compared to other wild pollinators. We also determined that the stingless bee species Meliponula bocandei and M. ferruginea are more efficient than honeybees in the pollination of sweet melon and cucumber. Recently, we also demonstrated that flower odor learning in stingless bees is species-specific, and that specific vibrational sounds are used to recruit foragers to crop plants. In an ongoing Mastercard Foundation-funded projects (Young Entrepreneurs in Silk and Honey [YESH] and More Young Entrepreneurs in Silk and Honey [MoYESH]) aimed at expanding commercial beekeeping, entrepreneurial and decent employment opportunities for >100,000 youth in Ethiopia, pollination of horticultural crops, especially vegetables using honeybees and stingless bees, along developed watersheds and rehabilitating landscapes, is being promoted as a complementary income generating opportunity while also providing diverse bee forages. Already, a cohort of 16,926 partner youth (59% female) have been recruited at project action sites and organized into 1,263 business enterprises designed to enhance agribusiness and income generation opportunities for rural youth and women in the country. Model beekeeping sites will be used to demonstrate managed beekeeping as an integral component of sustainable ecological farming that promotes healthy food, healthy farming, and a healthy environment.

Bee health R4D in support of pollination services

ICIPE has established the African Reference Laboratory for Bee Health (ARLBH) at its headquarters in Nairobi, Kenya, with four satellite stations in Liberia, Burkina Faso, Cameroon, and Ethiopia, as well as a diagnostic laboratory in Madagascar. This is the first of its kind in Africa. The ARLBH was accredited as a Collaborating Centre for Bee Health in Africa by the World Organization for Animal Health (OIE). Activities in the facility include assessment of environmental stressors like pesticides and habitat deterioration responsible for bee declines, development and establishment of diagnostic tools for pesticide residue analysis, surveillance for bee diseases, and establishing measures to protect them.

Improving habitat protection and restoration

Large-scale land transformation puts insect pollinators at risk, as land use change often results in degraded or fragmented habitats, that can no longer support pollinators due to the lack of nesting or foraging habitats. We have demonstrated that habitat deterioration, which includes natural forest loss, reforestation and afforestation with exotic tree species, negatively impacts species richness and diversity of stingless bees in sub-Saharan Africa. In fact, most stingless bee species are susceptible to habitat degradation since they tend to have very specific nesting requirements and only few species accept a broad range of natural and artificial substrates.

Strengthening pest and disease surveillance and management

Selected pollinator pests have been identified as being a particular concern to pollinator populations, including the wax moth (Galleria mellonella) and large and small hive beetles (Oplostomus haroldi and Aethina tumida) respectively. An initial survey provided high quality data that have been used, in combination with modeling approaches, to predict regions of high pest risk. The chemical and behavioral ecology of these pests has also been studied in detail, with the aim of developing control measures based on using chemical agents as attractants or repellents in traps. In Kenya, small hive beetles have also been identified as a major pest affecting stingless bee Meliponula species. Additionally, we have established that the Black Queen Cell virus that attacks honeybees can also be transmitted to stingless bees. Finally, we have also determined the resistance and tolerance mechanisms of African honeybees to the ectoparasitic mite Varroa destructor, potentially the most severe bee-pest. A plant-based bio-pesticide has been developed that is effective against the Varroa mite and has a repellent effect on the small hive beetle.

Decreasing the risk of pesticide use in crops and foraging plants, and adopting pollinator-friendly agricultural practices

While pesticide residue levels currently remain below international standard norms (e.g. EU standards), ICIPE and partners have observed an increase in pesticide residues in beehive products, which implies that pollinators are picking up pesticides applied to crops that could in turn affect their health. Pesticide use is increasing in sub-Saharan Africa, and ICIPE has piloted the use of ‘integrated pest and pollinator management (IPPM)’ to ensure that crop protection is harmonized with pollination services on pollinator-dependent crops such as avocado and cucurbits. In Kilimanjaro, Tanzania, and Murang’a, Kenya, we are implementing best-bet integrated pest management (IPM) package based on  fungal bio-pesticides, attract-and-kill products, and protein baits that enhance pollinator diversity while reducing pest populations (such as the oriental fruit fly — Bactrocera dorsalis — and the false codling moth — Thaumatotibia leucotreta) on avocado across landscapes. So far, more than 1,400 farmers in Murang’a have been trained on the use of IPPM, and many have adopted the practice to combat avocado pests without negatively impacting pollinators.

Understanding the bee microbiome to improve pollination services

Honeybees and stingless bees harbor diverse gut microbiota, which are critical to a variety of physiological processes — including digestion, detoxification, immune responses, and protection against pests and diseases. Surprisingly, whereas beekeeping has been widely promoted as a tool to mitigate poverty in tropical and subtropical regions of the world, no comprehensive studies of honeybee gut microbiota have been done in sub Saharan Africa where pollen and nectar resources are present year-round. Moreover, Africa hosts a highly significant diversity of bee species that might be associated with significant and uncharacterized gut microbe diversity selected for by different evolutionary pressures. ICIPE’s goal is to increase pollinator fitness and thus the pollination services they provide by investigating gut microbiota-host interactions. With the use of comparative genomics and microbiology tools, we are characterizing the nature of specific beneficial interactions. Results indicate that microbial abundance varies with geographical locations. We are currently investigating the parameters affecting this abundance as well as uncovering novel members of the microbiome that we found to be specific to Africa, in an effort to enhance pollinator health and pollination services.

Modeling climate change impact on pollinators

Climate shocks and land use change increasingly affect the life cycle as well as spatial and temporal distribution patterns of pollinators (e.g., honeybee, stingless bees), their pests, and the flowering plants upon which they depend for food and shelter. These habitat changes and climatic shifts have a trickle-down effect on pollination efficiency and thus food security. We are using replicable analytical methods and novel procedures for assessing the impact of climate and landscape change on the current and future distribution and abundance of honeybees, stingless bees, their pests, and flowering plants. Using long-term climate data with time-series satellite data variables overlaid on actual land surface properties and dynamics (i.e. changes in vegetation chlorophyll activity over time), we have developed accurate and realistic pest risk maps to guide interventions with regard to managing the pests of these pollinators using bio-pesticides without harming bees. Within the landscape mapping context, we have developed a sophisticated algorithm to map floral responses from spectral imagery. This is helping to understand the role of landscape fragmentation and the distribution, abundance, and temporal availability of flowering plants, pollinators, and pollination services. The knowledge on the value of natural habitats for bees within agro-ecological landscapes (using flowering and fragmentation maps) should be an incentive for the protection of these habitats.

Strengthening the capacity of farmers and national systems

Capacity building of farmers and national agricultural extension systems has been integral to building awareness of the important role pollinators play in improving food security. Training activities range from minimizing pesticide use, adopting pollinator-friendly agricultural practices, incentive to communities to support conservation of pollinators, and training of graduate students (PhD and MSc). Over 17,793 farmers and 816 extensionists have been trained across 21 Francophone and 23 Anglophone speaking countries across Africa. A total of 32 graduate students (PhD and MSc) have been trained across different countries (Kenya, Burkina Faso, Belgium, Uganda, Cameroon, Ethiopia, D.R. Congo, South Sudan, Nigeria, Ghana, Tanzania, Madagascar).

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A monarch butterfly sits on an orange flower
There were up to 70% fewer pollinators for plants in polluted air in the study. Image © Nikola Bilic/Shutterstock


Bees, butterflies and moths ‘confused’ by air pollution

By James Ashworth

First published 24 January 2022

Bees and butterflies are ‘confused’ by air pollution, making them less able to seek out the crops that both humans and insects depend upon.

In some cases, the presence of pollutants such as nitrogen oxides and ozone resulted in as much as a 90% decline in flower visits by pollinators.

Air pollution obscures the sweet smell of flowers, making it much harder for pollinators to find them.

Research led by the University of Reading found that insects including bees, flies, moths and butterflies were being impaired by air pollution, reducing pollination rates by as much as 31%. 

With 70% of the world’s crops, including apples, strawberries and cocoa, relying on insect pollination, scientists are concerned that the impact of common air pollutants goes far beyond impacts on human health.

Lead author Dr James Ryalls, says, ‘The findings are worrying because these pollutants are commonly found in the air many of us breathe every day. We know that these pollutants are bad for our health, and the significant reductions we saw in pollinator numbers and activity shows that there are also clear implications for the natural ecosystems we depend on.’

The findings of the study were published in the journal Environmental Pollution.

Cars in a queue with exhaust fumes rising around them
Common air pollutants include ground-level ozone, nitrogen oxides and sulphur oxides. Image © LanaElcova/Shutterstock

What is air pollution?

Air pollutants are commonly found across the world and include any substance that contaminates the environment by modifying the normal characteristics of the atmosphere.

After fuels are burnt, the waste products (as well as their impurities) can react in the atmosphere to produce a variety of harmful products. Common air pollutants include nitrogen oxides, ozone, sulphur oxides and particulates.

These have a diverse range of impacts, from causing acid rain to harming health. Air pollution has both short and long-term health impacts, from shortness of breath and exacerbating asthma to increasing the risk of heart failure.

As a result, the World Health Organisation (WHO) estimates that these pollutants cause around four million deaths a year, and suggest that 91% of the global population live in areas where air pollution exceeds recommended limits.

Aside from its impact on people, air pollution also impacts the natural world. In vertebrates, air pollution can cause similar issues as in humans, while pollutants like ozone and particulate matter can impair the ability of plants to photosynthesise.

The scents that plants produce to attract their insect pollinators are also affected by air pollution. While there are a number of ways insects find plants to pollinate, scent is one of the most important. However, air pollution can react with the compounds in these scents, making them much less recognisable to the insects they are supposed to be attracting.

The researchers wanted to investigate how this impacted pollinators in practice, by running an experiment testing their ability to find plants to pollinate.

Dr Robbie Girling, one of the paper’s co-authors, described the findings as ‘much more dramatic than we had expected.’

Bees landing on a yellow flower
Pollution reduced the visits of pollinators to the plants by up to 90% in some cases. Image © RUKSUTAKARN studio/Shutterstock

Pollinators in peril

The researchers used a purpose-built facility to regulate the levels of nitrogen oxides and ozone in a field environment, looking at the impacts these pollutants had on free-flying local pollinators and the pollination of black mustard.

They found that there up to 70% fewer pollinators for plants in polluted air, which led to a reduction in pollination of up to 31%.

With 8% of the value of agricultural food production worldwide dependent on pollinators, productivity declines from pollution could be causing billions of pounds worth of economic damage each year.

Furthermore, the levels of pollution used in the study were below the average maximum levels known from the real world, with scientists using concentrations around half of that deemed safe by the US government. 

These higher levels of air pollution in the real world could mean that the impacts on pollinators and other insect life are more severe than demonstrated in this study.

The UK Government says that it intends to tackle air pollution through a variety of techniques, including the consideration of an SMS air pollution alert scheme and aiming to set new targets for particulates and other pollutants. 

To find out levels of air pollution in your area, visit DEFRA’s forecasting site here.

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Why Giant Hornets Rub Their Abdomens on Bee Hives Before Attack


New research examines glands on the underside of Vespa soror wasps and the chemical signals they emit, which appear linked to behavior in which the wasps rub their bodies against honey bee hives to recruit nest mates for a group attack. (Photo by wklegend via iNaturalistCC BY-NC 4.0)

By Paige Embry

Paige Embry

For humans, communication is all about sight and sound, but, for many other organisms, chemicals are their primary language. We occasionally see this type of communication in action—the dog sniffing a rock and leaving his return message with a raised leg—but most of the chemical conversations going on around us are hidden from our perceptions.

We’ve identified some of these communications, and it’s pretty wondrous. Young queen honey bees, out for their nuptial flights, trail an it’s-time-to-mate scent. Pathogenic bacteria lie quietly inside a host and send out “I’m here” signals, releasing their toxins only when enough are present to potentially overcome the host’s immune system. A tree under attack may release chemicals that nearby relatives recognize as signs of impending disaster, allowing them to prepare their own defensive weaponry. Despite discoveries like these, we still understand little of the chemical conversations floating around us.

study published in November in the Annals of the Entomological Society of America opens a window onto this means of communication for one sophisticated insect predator, Vespa soror, a giant hornet that is kin to the one that sparked a media frenzy in 2020.

Vespa soror, like its infamous cousin, is a highly social insect whose workers occasionally coordinate to attack a honey bee colony en masse. These attacks happen in the fall when hornet colonies have grown large and have many mouths to feed. Heather Mattila, Ph.D., a professor at Wellesley College, is lead author of the Annals paper. (Her work finding that Apis cerana honey bees emit alarm sounds to warn colony members of hornet attacks has also recently earned public attention.) She says that, in typical giant hornet behavior, individuals grab whatever food they can get on their own. Come fall, however, they sometimes switch to group predation, “this full court press effort to try and take over a whole colony.” How V. soror hornets choose a honey bee colony for mass attack? And how do they let their relatives know?

The van der Vecht and Richards’ glands, found only in certain eusocial wasps in the Vespinae and Polistinae subfamilies, are located on the underside of the abdomen. Shown here is an external side view (A) of the posterior abdomen of a Vespa soror worker. The black rectangle indicates the approximate area shown in microscope view (B), where dotted ovals indicate the gland locations. (S5 and S6 indicate metasomal sternites 5 and 6.) (Image originally published in Mattila et al 2021, Annals of the Entomological Society of America)

Scientists know that social insects communicate with each other (and sometimes other species as well) via chemicals released from exocrine glands—glands that secrete something outside the animal’s body. In this study, Mattila and colleagues investigate two of those glands: the van der Vecht and Richards’ glands. These glands are found only in certain eusocial wasps in the Vespinae and Polistinae subfamilies. No other wasps, bees, or ants have these glands. The researchers looked in detail at the structure of the glands, a first step in better understanding their purpose. They also studied the hornets’ rubbing behavior at a honey bee apiary to try and assess which glands are involved and the rubbings’ role in mass attacks. (See videos below.)

Researchers observing Vespa soror wasps visiting a bee hive recorded their behavior in which they rubbed their abdomens on the hive near its entrance. Each white dotted line traces the path of the wasps’ rubbing. The rubbing appears to leave a chemical signal to other wasps to recruit them for a group attack on the hive, and a new study suggests two glands found on the underside of V. soror abdomens are likely involved in this chemical signaling. (Image originally published in Mattila et al 2021, Annals of the Entomological Society of America)

Both glands are located toward the end of the gaster—the part of a hymenopteran that is behind the “waist.” The Richards’ gland is smooth while the van der Vecht gland has a large brush of hair. Each gland is tucked under a sternite—one of the little plates on the underside of an insect. In certain body positions a gland is exposed, and in others the sternite acts as a kind of cap. “They have this structure that allows them to produce the pheromone but then release it to the world when they change their body posture, and part of that change in body posture could very well be rubbing,” Mattila says.

Because the glands are on the underside of the insect, it’s difficult to see which are involved in the rubbing. Nevertheless, the authors write, “Observations confirm that the van der Vecht gland is exposed during gastral rubbing but that the Richards’ gland and glands associated with the sting apparatus may also contribute to a marking pheromone.”

The scientists recorded V. soror activity over several days at an Apis cerana apiary in Vietnam. Lots of hornets were present during the study period. “Just hornets at a salad bar,” Mattila says, “grazing and grabbing bees,” and sometimes rubbing their hind ends on nest boxes or overhead vegetation. Some colonies weren’t marked or received only a rub or two. “We saw lots of marking going on that didn’t lead to a massive attack,” Mattila says. Some colonies, however, were heavily rubbed—and that heavy marking mattered. At one colony that received 26 rubbings over three hours, the hornets had, the authors write, “transitioned from hunting to attempting to breach the nest entrance.”  Mattila says, “we feel pretty confident these things are linked.”

Mattila notes that a lot more work needs to be done to understand how giant hornets communicate. “I kind of cringe sometimes thinking about this whole ‘murder hornet’ label, because these are really incredible animals. They are really beautiful creatures that are doing something hardly any other social insect does,” Mattila says. “And it’s fun to see up close how their parts are built for this.”Video Player00:0000:001. “Vespa soror rubbing bee hive”2. “Vespa soror rubbing bee hive”

Researchers observing Vespa soror wasps visiting a bee hive recorded their behavior in which they rubbed their abdomens on the hive near its entrance. The rubbing appears to leave a chemical signal to other wasps to recruit them for a group attack on the hive, and a new study suggests two glands found on the underside of V. soror abdomens are likely involved in this chemical signaling. (Videos originally published supplementary to Mattila et al 2021, Annals of the Entomological Society of America)

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Linking the Morphology of Sternal Glands to Rubbing Behavior by Vespa soror (Hymenoptera: Vespidae) Workers During Recruitment for Group Predation

Annals of the Entomological Society of America

Paige Embry is a freelance science writer based in Seattle and author of Our Native Bees: North America’s Endangered Pollinators and the Fight to Save Them. Website: www.paigeembry.com.

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Chemical crop protection affects bee reproduction over several generations

A new study from researchers at the University of California, Davis, finds that chemical crop protection not only directly affects bee health, but effects from past exposure can carry over to future generations. The study, published in the journal Proceedings of the National Academy of Sciences, suggests that bees may require multiple generations to recover from even a single application.

Bees play a critical role in agricultural ecosystems, providing pollination for many important crops. In most agricultural areas, bees may be exposed to chemical crop protection multiple times, over multiple years. Studies to date have only looked at exposure to chemical crop protection in one life stage or over one year.

“It was important for us to understand how exposure persists from one generation to the next,” said lead author Clara Stuligross, a Ph.D. candidate in ecology at UC Davis. “Our findings suggest we need to be doing more to help mitigate risks or we limit critical pollination services.”

Reproduction drops
In the study, the blue orchard bee was exposed to imidacloprid — the most commonly used neonicotinoid in California — according to amounts recommended on the label. Neonicotinoids are a class of insecticides chemically related to nicotine. Stuligross said the exposures were similar to what the bees would experience in the field. Female bees that were exposed to the insecticide as larvae had 20% fewer offspring than bees not exposed. Those bees that were exposed as larvae and as adults had 44% fewer offspring.

“We gave them one application in the first year and one in the second — that’s a pretty standard exposure. Even then, we saw strong results that added up, each exposure reducing fertility,” said Stuligross.

Populations affected
Because the impacts of insecticides tend to be additive across life stages, repeated exposure has profound implications for population growth. The research showed that bees exposed to neonicotinoids in both the first and second years resulted in a 72% lower population growth rate compared to bees not exposed at all. Neonicotinoids also persist in the environment long after application.

The study reveals how past chemical crop protection exposure can have lasting impacts, said co-author Neal Williams, professor of entomology at UC Davis. “One could draw parallels to human health where impacts early in development show up much later in life,” he said. “We just didn’t know the same was true for bees. Now we do and we need to continue to manage risks appropriately.”

For more information:
University of California Davis 
One Shields Avenue, Davis
California 95616, US

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Bees deliver organic fungicide to crops while pollinating flowers

Sustainable farming technology company Bee Vectoring Technology (BVT) has created a natural fungicide powder that eliminates mold on growing fruits. The preventative measure is delivered by bees doing what they do best – pollinating flowers. They take it directly to the flower, rather than spreading it all over the plants and soil as a traditional spraying system does. This bee-based system has been dubbed ‘natural precision agriculture’.

The fungicide is dispensed through the openings of the hives. As bees leave the hive, they move through the powder, picking up a thick coating on their legs and wings. When they land on a flower to collect pollen, the powder naturally falls off.  

With bee populations all over the world declining in number, lessening environmental pollution is a necessity for their survival. As the bees deliver the fungicide, they are reducing the need for chemicals. Growers can rent or buy hives of bees for a season or full-time, and beekeepers monitor hive health and the needed volumes of fungicide for each crop. The fungicide is available as a single ingredient or a stackable mix of powders, depending on what crop is being protected.

“Spraying products onto crops is inherently inefficient. Only a small amount of what is sprayed on an acre of farm lands on the crop flower,” explains Ashish Malik, CEO of BVT. “On the other hand, bees only visit flowers, and so all of what they are carrying can be used to inoculate the crop with a beneficial microbe to help it fight diseases and pests.”

A number of innovations are focusing on ways to help improve the resilience of hives, with Springwise spotting several new designs. These include a hive that mimics the shape of a tree, and another made from mycelium that helps repel deadly mites. 

For more information:
Bee Vectoring Technologies International 
T: (647) 660-5119

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View as a webpage ARS News Service ARS
News Service Handfeeding a honey bee.
Scientists at the ARS Bee Research Laboratory in Beltsville, Md., use the handfeeding technique to deliver pathogens and medicines to bees.

Natural Products May Be Buzzworthy Solutions for Honey Bees’ Health
For media inquiries contact: Jessica Ryan, (301) 892-0085
November 29, 2021 The buzz about natural products is not just for humans. United States Department of Agriculture (USDA), Agricultural Research Service (ARS) researchers from the Bee Research Laboratory in Beltsville, Maryland, and collaborators found some natural products’ medicinal properties reduced virus levels and improved gut health in honey bees. Among the study’s results, which were recently published in Applied Sciences, researchers found a significant reduction in virus levels in bees fed raw cacao and hesperidin, a plant chemical commonly found in citrus fruits and other fruits and vegetables. There were also lower levels of viruses in bees fed chrysin, curcumin and vanillin. Chrysin is a chemical found in honey and various plants such as passionflower and silver linden. Curcumin is a bright yellow chemical produced by plants and is known for giving turmeric its distinctive color. Vanillin is a chemical compound of the extract of a vanilla bean and major flavor component of vanilla. The results also showed that some natural products had positive impacts on bees’ gut health and immune response. For example, bees fed Vitamin E had significantly decreased levels of Gilliamella, a gut bacterium. In addition, there were also lower levels of Gilliamella in bees fed curcumin, vanillin and hesperidin. While Gilliamella can be beneficial for honey bees, too much of the gut bacterium can negatively impact their health. “Gilliamella is a common bacterium in honey bees―even healthy ones,” said Jay Evans, research entomologist for the Bee Research Laboratory. A gut bacterial imbalance could be bad for bees. If Gilliamella levels are high, then Gilliamella could take the place of other core bacteria. If bee diets or treatments help maintain a good mix of ‘good’ bacteria in bees’ guts, then this seems to help strengthen their immune responses, according to the study’s results. The 20 natural products used in the study included native extracts and individual compounds known to support immunity, have antiviral or antimicrobial properties, and/or control parasites and pests. Scientists researched these natural products as possible safer, cost-effective alternatives to antibiotics and synthetic chemicals. Understanding these natural products’ effects can also help scientists determine better crops and flowers for bees’ diets.   “Many of the natural products tested are recognized as safe components of the food supply and are potentially less expensive to produce,” said Evans. “These results could also inform us on possible, healthier crops and flowers for bees. Bees foraging on crops or non-crop plantings of flowers that provide these benefits could naturally have better health.” The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $17 of economic impact. Interested in reading more about ARS research? Visit our news archive U.S. DEPARTMENT OF AGRICULTURE
Agricultural Research Service

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Pesticides can harm bees twice—as larvae and adults

Impacts on pollinators may be worse than thought

Blue orchard bees
Blue orchard bees (Osmia lignaria) live a solitary life.JOE DLUGO/ALAMY STOCK PHOTO


Honey bees have a reputation for working hard, but carpenter bees and other bee species that don’t live in colonies might be even more industrious. For these so-called solitary bees, there is no dedicated worker class to help with rearing young and foraging. “Each female is kind of like a lone wolf,” says Clara Stuligross, a Ph.D. student at the University of California (UC), Davis.

Now, a study by Stuligross and colleagues tallying the detrimental impacts of a key pesticide on reproduction of a solitary bee species adds to growing evidence that such insects, which make up the vast majority of bees species, are vulnerable to the compounds just like their more social counterparts. Their finding suggest the harm of pesticides can accumulate over multiple generations, which could exacerbate the loss of species that provide valuable pollination for farms and ecosystems.

The work demonstrates that chronic pesticide poisoning can cause “meaningful and significant impacts” on bees, says Nigel Raine, a bee ecologist at the University of Guelph who was not involved with the study. “That’s really quite important.”

Of all the types of pesticides that harm bees, one is particularly insidious. Known as neonicotinoids, they are coated on seeds or sprayed on soil. Then they permeate the tissue of plants, eventually showing up in pollen and nectar. The pesticides disrupt learning and memory in honey bees and several studies have shown solitary bees suffer the same kind of damage. At higher levels, the chemicals impair reproduction, such as by reducing the viability of sperm, leading to fewer offspring. Yet little research has examined how neonicotinoids might harm pollinators throughout their life cycle.

So Stuligross and her UC Davis adviser, ecologist Neal Williams, designed a study to find out. They looked at the blue orchard bee (Osmia lignaria), a solitary species native to North America that farmers sometimes use to pollinate almond and other fruit trees.

Stuligross set up 16 cages, each about the size of two small cars, and planted three species of wildflower to feed the bees. In half of the cages, she drenched the soil with imidacloprid, as farmers do with this common neonicotinoid. The eight females bees in each cage had the company of 16 males, and they were provided with nesting space (holes drilled in wood) and a supply of mud that insects use to create cells for their brood inside the holes. Other solitary bee species do this as well, which is why they’re also called mason bees.

After the females mated, they laid eggs inside the holes, provided each egg with a ball of pollen and nectar, and sealed them up in individual cells made of mud. Meanwhile, the females were themselves consuming pesticide-contaminated pollen and nectar. They seemed sluggish and needed longer to find their holes, for example, and they laid fewer eggs than healthy bees. “They just seemed like they weren’t well,” Stuligross says.

Adult blue orchard bees typically only live for a few weeks. After they die, their larvae develop while feeding on the food left behind. This exposure to the pesticide had lasting harm. Bees that had consumed pesticides had 30% fewer offspring, compared with bees that had grown up without pesticides.

To figure out the effect of chronic exposure, Stuligross drenched the soil in some cages again the next year. Fertility suffered even more. Those insects with a double dose over the 2 years—they had consumed pesticides as larvae in the first year of the experiment and then again as adults, when they collected pesticide-laden pollen from flowers—laid about 20% fewer eggs than did bees that had only been exposed as larvae, Stuligross and Williams report today in the Proceedings of the National Academy of Sciences.

“Clearly, this paper shows that there are substantial impacts,” Raine says.

Over two generations, the damage to bee fertility adds up: The number of offspring would be about 75% less than for bees never exposed to imidacloprid, the team concludes. Such a reduction in fertility could tip populations into a long-term decline in the real world, where uncaged bees are not protected from predators or provided with easy access to unlimited food, Stuligross says.

“This is very important because it can explain at least partly the decline of bees worldwide,” says Fabio Sgolastra, a bee ecologist at the University of Bologna. “This is another piece of the puzzle showing that neonicotinoids are bad for solitary bees.” Government regulators should start to consider the risk to solitary bees, and not just honey bees, Sgolastra and others say. Although solitary bee species have not been commercialized as much as honey bees, they provide essential—and free—pollination for many farmers.

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RAZOR 19:37, 18-Oct-2021Translate How these bees are reducing the need for harmful pesticidesCGTN


How can the world be fed without the use of pesticides? One company thinks it has the answer – and bees are going to help it achieve this. 

The company BeeVT, or Bee vectoring technology, has developed a natural fungicide to treat certain crops. And instead of spreading it with fossil fuel-run machines it has got bees on board, harnessing their natural pollination process to deliver targeted crop controls.09:4838

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The yellow-legged Asian hornet (Vespa velutina nigrithorax) is an
invasive species that poses a particular threat to the European honey
bee (Apis mellifera). This study reports on the management of Asian hornet
incursions in the UK, including the use of nest dissection and microsatellite
marker analysis (a form of genetic testing) to determine the relatedness and
reproductive status of detected nests and hornets.

The yellow-legged Asian hornet (Vespa velutina nigrithorax) is an invasive species in Europe. Once
established, the hornet presents a threat to native invertebrate species — particularly the European
honey bee (Apis mellifera), which is vulnerable to predation. Since 2004, Asian hornet populations
have colonised parts of France, Spain, Portugal, Belgium, Italy, Germany and some of the Channel
Islands. Their nests and lone individuals have also been detected in other countries, including the UK.
Pollinators are vital for our food production. By helping plants to reproduce, pollinators supporting a
supply of healthy and economically valuable food for humans, while supporting entire ecosystems.
The EU Pollinators Initiative is a strategy for Member States to address the decline of pollinators in
the EU and to support global conservation efforts.

In the study, British researchers describe the management of Asian hornet incursions, including the
use of nest dissection and microsatellite marker analysis (a form of genetic testing) to determine
the relatedness and reproductive status of detected nests.

In the UK, the Non-Native Species Secretariat and National Bee Unit respond to all reports of foraging
Asian hornets and use trajectory tracking techniques to locate and destroy nests. Between the time
of the first detection in 2016 and the end of 2019, a total of nine nests were detected. Lone adult
individual hornets were sampled from seven additional sites during the same time period.

After destruction, all nests were sent to a laboratory for dissection. For each, the number of adult
hornets, sex ratio, and mass of individuals was recorded. The diameter of the nest and each
individual comb was also measured, and the life stages present in the nest were determined.
Tissue samples from the nests and lone adult hornets were then collected for microsatellite
marker analysis. Microsatellites are segments of DNA where a short section of the nucleotide (a
basic building block of nucleic acid — an organic substance present in living cells such as DNA)
sequence repeats and are useful for measuring genetic variation.

The results of these analyses suggest that the Asian hornet has not established a population in
the UK, and that the detected nests and lone individuals are likely the result of separate incursions
from the European continent. None of the nests were found to have produced the next generation
of queens, and follow-up monitoring in affected regions detected no new nests in later years.
Diploid males (i.e. those having two identical chromosomal sets — indicative of inbreeding) were
also found in many UK nests, while microsatellite analysis showed that nests had low genetic
diversity and the majority of queens had mated with only one or two males. All nests were found
to have derived from continental Europe, rather than from Asia or elsewhere in the UK.

The researchers report such insights are used to guide real-time decision making in the UK. Data
on the reproductive status of the nest are used to inform the level of monitoring in the area
implemented in subsequent years. Determining whether captured individuals belong to one or
more nests also enables inspectors on the ground to know how many nests they are searching
for. For this reason, this research may be of interest to policymakers, particularly those concerned
with the management and control of invasive species and the protection of European apiculture

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Fungus fights mites that harm honey bees

New fungus strain could provide a chemical-free method to help honey bees


Date:May 27, 2021Source:Washington State University

Summary: A new fungus strain bred in a lab could provide a chemical-free method for eradicating mites that kill honey bees. Varroa destructor mites play a large role in Colony Collapse Disorder, which destroys thousands of bee colonies every year. Share:


A new fungus strain could provide a chemical-free method for eradicating mites that kill honey bees, according to a study published this month in Scientific Reports.

A team led by Washington State University entomologists bred a strain of Metarhizium, a common fungus found in soils around the world, to work as a control agent against varroa mites. Unlike other strains of Metarhizium, the one created by the WSU research team can survive in the warm environments common in honey bee hives, which typically have a temperature of around 35 Celsius (or 95 F).

“We’ve known that metarhizium could kill mites, but it was expensive and didn’t last long because the fungi died in the hive heat,” said Steve Sheppard, professor in WSU’s Department of Entomology and corresponding author on the paper. “Our team used directed evolution to develop a strain that survives at the higher temperatures. Plus, Jennifer took fungal spores from dead mites, selecting for virulence against varroa.”

Jennifer Han, a post-doctoral researcher at WSU, led the breeding program along with WSU assistant research professors Nicholas Naeger and Brandon Hopkins. Paul Stamets, co-owner and founder of Olympia-based business Fungi Perfecti, also contributed to the paper. Stamets is a fungi expert, well-known for using several species in applications ranging from medicine to biocontrol.

Varroa destructor mites, small parasites that live on honey bees and suck their “blood,” play a large role in Colony Collapse Disorder, which causes beekeepers to lose 30-50% of their hives each year. The mites feed on bees, weakening their immune systems and making them more susceptible to viruses.

The main tools beekeepers use to fight varroa are chemicals, such as miticides, but the tiny pests are starting to develop resistance to those treatments, Naeger said.

Metarhizium is like a mold, not a mushroom. When spores land on a varroa mite, they germinate, drill into the mite, and proliferate, killing it from the inside out. Bees have high immunity against the spores, making it a safe option for beekeepers.

Stamets, who did some of the initial testing with Metarhizium that showed the fungus couldn’t survive hive temperatures, was impressed by the work done by the WSU researchers.

“Science progresses through trial and error, and my technique wasn’t economical because of the hive heat,” he said. “But Jennifer did enormous amounts of culture work to break through that thermal barrier with this new strain. It’s difficult to really appreciate the Herculean effort it took to get this.”

Han and Naeger screened more than 27,000 mites for levels of infection to get the new strain.

“It was two solid years of work, plus some preliminary effort,” Han said. “We did real-world testing to make sure it would work in the field, not just in a lab.”

This is the second major finding to come from WSU’s research partnership with Stamets involving bees and fungi. The first involved using mycelium extract that reduced virus levels in honey bees.

“It’s providing a real one-two punch, using two different fungi to help bees fight varroa,” Stamets said. “The extracts help bee immune systems reduce virus counts while the Metarhizium is a potentially great mite biocontrol agent.”

The next step is to seek approval from the Environmental Protection Agency to use Metarhizium on hives used in agriculture. The team must also finalize delivery methods for beekeepers to apply the fungus in hives.

“We hope in 10 years that, rather than chemical miticides, Metarhizium is widely used to control Varroa mites,” Sheppard said. “And that the mite problem for beekeepers has been significantly reduced.”

The team thinks the methods they developed to evolve Metarhizium for varroa control could be used to improve biocontrol agents in other crop systems as well.

The majority of the funding for this work came from private donations from individuals and foundations. Additional funding came from Washington State Department of Agriculture (WSDA) Specialty Crop Block Grant K2531 and the USDA National Institute of Food and Agriculture, Hatch 1007314.

Story Source:

Materials provided by Washington State University. Original written by Scott Weybright. Note: Content may be edited for style and length.

Journal Reference:

  1. Jennifer O. Han, Nicholas L. Naeger, Brandon K. Hopkins, David Sumerlin, Paul E. Stamets, Lori M. Carris, Walter S. Sheppard. Directed evolution of Metarhizium fungus improves its biocontrol efficacy against Varroa mites in honey bee coloniesScientific Reports, 2021; 11 (1) DOI: 10.1038/s41598-021-89811-2

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