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Extreme heat waves could threaten honeybee fertility or cause sudden death

Extreme heat waves could threaten honeybee fertility or cause sudden death

Extreme heat waves threaten honeybee fertility and trigger sudden death

In June 2021 temperatures rose to 42 C in Western Canada, with Lytton (B.C.) registering 49.6 C. Canada’s hottest temperature. Wildfires erupted in the province, sparking a 56-day state emergency Nearly 600 additional sudden deathsComparatively to the same period in 2020.

However, the heat was not just affecting humans. Okanagan Valley beekeepers reported Unusual deaths in honeybee colonies, drones and queens. Drones, which are the reproductive men, Ejaculate spontaneouslyWhen they die of stress, Emily Huxter (a beekeeper from Armstrong), will help. We saw dozens more dronesShe was suddenly found lying on her back, with her male bits peeking out from the lids of her beehives.

A honeybee drone that was killed by the heat wave in British Columbia, June 2021.
(Emily Huxter)

I research how heat stress affects honeybees, and Huxter’s observations reflect what I’ve seen in the lab. Our experiments have shown that honeybees are more responsive to heat than temperatures of 42 C after six hours. 50% of male honeybees are killed. The results were alarming but conservative in comparison to previous work. Other researchersResearchers have found that 42 C exposure for as little as four hours can cause drone deaths of up to 77%.

This means that after a heat wave, new queens — the reproductive females — will have fewer opportunities to mate. Colonies that are headed by poorly mated Queens are More likely to fallThis could cause problems for farmers who depend on honeybees for pollination. It also highlights the danger heat waves pose for wild insects.

Death isn’t the only damage

Worryingly, male fertility may begin to decline long before the drones die. After just two hours at 42 C, the average age of male fertility is about one-thirdPerishance of drone ejaculates sperm cells. This means that male bees who survive heat events are likely to have reduced fertility. Huxter’s dead drones indicate that the temperatures last summer clearly reached the fertility-damaging range, even for those that survived.

Queen honeybees mate, and keep sperm inside a specialized storage system over their lifetime. One to three years. But even stored fertilm cells are not immune to hot temperatures. Queens exposed to temperatures above 38 C for two hours or more usually survive, but the viability of the stored sperm drops to what beekeepers consider to be “Poor quality.”

In terms of survival, large colonies seemed to do well in the 2021 heat dome. However, even though most bees survived, the insidious loss to queens and drone fertility means that they could still be harmed.

Queen honey bee
Canada imports around 250,000 queen honeybees annually.
(Alison McAfee)

Wild insects are important too

Extreme heat affects not only honeybees but also other insects. Scientists predict that this will continue. Heat waves are getting worseCould impair fertility beetles, Bumblebees, Flies, moths Wasps — and those are just some of the ones we know about.

The trends are even more alarming for whole populations. The flour beetle Tribolium castaneumEven though they have never experienced heat, sons of heat-stressed dads may experience impaired fertility. Scientists predict widespread. Wild bumblebees decline as the frequency of heat events increase to “untenable” extremes. The temperature at which male fruit flies lose fertility does a better job of Explain their geographical distributionThe more than The hottest temperatures they can survive do.

Bumble bee on blueberry flowers
Blueberry pollination is done primarily by honeybees. However, wild bumblebees also make excellent pollinators.
(Alison McAfee)

Honeybees are adaptable to their environment and can be trained to adapt to hotter temperatures. Subspecies of the Middle East honeybee have evolved. Higher toleranceHotter and more arid than Europeans, for example. However, colonies established in Canada have shown this. Evidence of selectionFor cold tolerance

Honeybee colonies only produce new queens once a calendar year when they prepare to swarm or create a new colony. This means that honeybee colonies are slower to reproduce than mosquitoes and they are less able to adapt to changing conditions.

The queen honeybees are able to compensate for this by mating with multiple males – provided they haven’t been killed in a recent heatwave. This increases the genetic diversity in their colonies, which is what natural selection relies on.

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Canadian beekeepers also import around 250,000Each year, queens are born, bringing with them a steady flow of new genetics. Today, the queens mostly arrive from California and Hawaii. However, other exporters include Australia and New Zealand, Chile, Australia, Ukraine, and many others. This can be a blessing or a curse depending on how genetic diversification is balanced with local adaptation. However it does encourage new combinations that could help address new challenges.

The bellwethers of the universe are the bees

Despite the beekeepers’ losses, honeybees will almost certainly survive as the climate changes. However, not all insects will have the same luck. Bumblebee, wasp, and many ant queens are also produced each summer. You will usually mate with one or more malesThey may not have as many opportunities for gene transfer and are less likely to adapt.

Heat waves are not the only problem that insects face. It is also important to consider habitat loss, pesticides, pathogens, and other issues.. Two months later, British Columbia lifted the emergency state. a devastating floodFamilies were displaced again, and there were untold numbers native bees hibernating on the ground.

Insects are important players in ecosystems across the globe, and with good reason. Many terrestrial species are already in declineIt is important to research how climate change will affect their fertility. Honeybees are important because they pollinate crops and we depend on them. But, they are not the only ones we pay attention to. We know that the conditions during the 2021 heat dome are sufficient to reduce fertility of honeybees, which should raise alarm bells about the wild insects who don’t have keepers.

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