Bees face many challenges – and #ClimateChange is increasing the pressure – The Conversation #ActOnClimate

The extreme weather hitting much of the United States in 2022 isn’t just affecting people. Heat waves, wildfires, droughts and storms also threaten many wildlife species, including some already facing other stresses.

I have been researching bee health for over 10 years with a focus on honey bees. In 2021, I first started hearing from beekeepers about how extreme drought and rain was affecting the health of the bee colony.

In 2021, drought conditions in the western United States dried up bee forage—the flower nectar and pollen that bees need to produce honey and stay healthy. Heavy rain in the Northeast has limited the hours bees can fly to forage.

In both cases, managed colonies—hives kept by humans for honey production or commercial pollination—were starving. Beekeepers had to feed their bees more sugar water and pollen than usual to keep their colonies alive. Some beekeepers who have been in the business for decades shared that they lost 50% to 70% of their colonies in the winter of 2021-2022.

These weather conditions likely affected wild and native bees as well. And unlike managed colonies, these important species didn’t receive supplements to buffer them under harsh conditions.

Each year, the U.S. Department of Agriculture and the Environmental Protection Agency host federal pollinator experts to share the latest scientific findings on the health of bees and pollinators and assess the status of these important insects, birds, bats and other species. One clear takeaway from this year’s meeting was that climate change has become a new and frightening stressor for bees, potentially exacerbating previously known problems in ways that scientists cannot yet predict but must prepare for.

Australia’s recent bushfires and drought have destroyed millions of bees and countless hectares of habitat. Australian honey may soon be imported and vital pollinators will be scarce for agriculture. One third of the world’s food depends on bee pollination.

The trouble Varroa ticks

Pollinators contribute an estimated US$235-577 billion annually to global agriculture based on the value of the crops they pollinate. Understanding and mitigating the effects of climate change on pollinators is key to supporting healthy ecosystems and sustainable agriculture.

Bee health first gained widespread attention in 2006 with the emergence of Colony Collapse Disorder. This phenomenon results in the disappearance of most of the adult worker bees in the colony, leaving the honey and pollen stores and some nurse bees behind to care for the queen and the remaining immature bees. . In the last five years, reported cases have decreased significantly. Now researchers are focusing on what beekeepers call the “four Ps”: parasites, pathogens, pesticides and poor nutrition, as well as habitat loss for wild and native bees.

It has been one of the most serious threats to honey bees in the last few decades Varroa destroyer, a crustacean parasitic mite that feeds on the fat body tissue of honey bees. A fat body is a nutrient-rich organ that functions like the liver in mammals. It helps bees maintain a strong immune system, metabolize pesticides and survive the winter.

These are vital functions, so controlling mite infestations is important to bee health. Varroa can also transmit deadly pathogens such as deformed wing virus to honey bees.

Tick ​​populations are difficult to control. This requires using an insecticide on an insect colony, or as beekeepers say, “trying to kill a bug.” It is difficult to find a formula strong enough to kill mites without harming the bees.

Monitoring Varroa requires considerable skill and labor, and ticks can become resistant to treatments over time. Researchers and beekeepers are working hard to breed Varroa-sustainable bees, but mites continue to plague the industry.

Microdoses of pesticides

Pesticides also harm bees, especially products that cause sublethal or chronic bee health problems. Exposure to sublethal pesticides can impair bees’ ability to forage, produce healthy larvae, and fight viruses and mites.

However, fatal toxicity can be difficult to document and understand. Many factors influence the response of bees to agrochemicals, including whether they were exposed as larvae or adults, the mix of chemicals to which the bees were exposed, weather conditions at the time of application, and how healthy the bee colony was at initial exposure.

Researchers are also working to understand how soil pesticides affect ground-nesting wild bees, which make up more than 70% of the US native bee population.

Junk food diets

Like many other species, bees are losing the habitats and food sources they depend on. This happens for many reasons.

For example, uncultivated land is being converted into cropland or is being appropriated around the world. Large-scale agriculture focuses on the mass production of a few commodities, which reduces the amount of nesting habitat and forage resources available to bees.

Many farmers often remove pollinator-friendly plants and shrubs growing around farm fields to reduce the risk of attracting animals such as deer and rodents, which can spread pathogens that cause foodborne diseases. Studies show that these efforts harm beneficial insects and do not improve food security.

With the loss of diverse and healthy bee forage, beekeepers are increasingly feeding their bees sugar syrup and non-nutritive food additives such as nectar and pollen from pollen.

Climate change is a force multiplier

Researchers don’t know exactly how climate change will affect bee health. But they suspect it will add to existing stresses.

For example, bees will be exposed to more pesticides if pest pressure increases for farmers. Excessive rain can disrupt foraging bees. Wildfires and floods can destroy bee habitats and food sources. Drought can also reduce available forage supplies and discourage land managers from planting new areas for bees as water becomes less available.

Climate change may also increase its prevalence Varroa and other pathogens. Warmer fall and winter temperatures extend bee foraging time. Varroa travel with foraging bees, so longer foraging periods provide a larger window of time for mites and the viruses they carry to spread between colonies. Higher mite populations in hibernating bee colonies will compromise colony health and increase winter losses.

Research has already shown that climate change is disrupting the seasonal relationship between bees and flowers. Because spring comes earlier in the year, flowers bloom earlier or in different regions, but bees may not be available to feed on them. Even if flowers bloom at normal times and places, they may produce less nutritious pollen and nectar in extreme weather conditions.

Research that analyzes the nutritional profiles of bee forage crops and how they change under different climate scenarios will help land managers plant climate-resilient crops for different regions.

Creating safe bee spaces

There are many ways to support bees and pollinators. Planting pollinator gardens with regional plants that bloom year-round can provide much-needed forage.

Ground-nesting native bees need open and undisturbed patches of soil without mulch or other ground cover. Gardeners can clear some soil in a sunny, well-drained area to create special nesting sites for bees.

Another important step is to use integrated pest management, a land management approach that minimizes the use of chemical pesticides. Anyone interested in helping monitor native bees can join community science projects and use phone apps to submit data.

Most importantly, educating people and communities about bees and their importance to our food system can help create a more pollinator-friendly world.

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