There is little chance that honey bees will go extinct – even with the threat of the deadly Varroa mite. Honey bees are mostly managed and domesticated by beekeepers who can oversee them and work to make sure they are healthy.
But non-managed bees are not so lucky. Bumblebees are greatly threatened by increasingly hotter temperatures, the combination of habitat loss and pesticide use is a real threat to bees that must take care of their own.
Are Bees Endangered?
Even only casual consumers of science news, have read or viewed a story about the crisis facing bees. The most recognized bees – honey bees and bumblebees – have received a lot of press about their plight during the past couple of decades.
And it is true that around 2006, honey bees were falling victim to a phenomenon called Colony Collapse Disorder (CCD), in which the majority of worker bees in a hive mysteriously disappear, leaving the queen and only a few nurse bees to take care of the queen’s brood. CCD did cause many honey bee colonies to “collapse” during that time, but since then there has been an increase in the number of hives, and it is understood that honey bees are no longer in grave danger.
But honey bees are mostly a managed species – taken care of by beekeepers – so they are at an advantage compared to the 99% of other species that are on their own. And although there are seven species that have been placed on the Endangered Species List, honey bees are not one of them, and neither are bumblebees.
But there is still evidence that thousands of species of native bees are at risk. The most comprehensive study of global bee decline, published in 2017, found that 40% of pollinators (and most were bees) could face extinction if threats are not mitigated.
Are Honey Bees Endangered?
Despite the fact that honey bee colonies are no longer collapsing, beekeepers still lost between 35 and 40 per cent of their colonies in 2018, according to the most recent reported data.
The biggest threat facing honey bees today is a tiny parasite called the Varroa mite, also known as the Varroa destructor. This mite is so devastating to honey bee colonies because it attaches to the bee and sucks its “fat body” – tissue that contributes to its immune system and also helps it to remove toxins from pesticides.
Additionally, the Varroa mite is a vector for several other bee viruses, such as deformed wing virus and acute bee paralysis virus. These viruses can quickly spread within and between honey bee colonies.
While beekeepers can try to ward off Varroa mites with miticides, the Varroa mite has become more resistant to them over time. If this mite cannot be contained, honey bee colonies could be at greater risk than they were during the period when CCD was occurring. Considering that honey bees pollinate more than 80 crops and contribute $15-$20 million to the U.S. economy each year, it is crucial that beekeepers find a way to mitigate this threat.
Are Bumblebees Endangered?
The number one threat facing bumblebees is climate change, according to the researcher, Peter Soroye. Along with two other colleagues, Soroye found that the bumblebee’s rate of decline was so severe that it could disappear within a few decades.
The study, published in the Journal Science in early 2020, developed a new measurement of temperature to determine how tolerant particular species are to increasing temperatures. They used available data for 66 different species of bumblebees to map out where bees were historically and where they are today.
The research team found that populations were disappearing in regions that had shown temperature increases, and they felt confident they could predict how hotter temperatures would impact individual species and larger bumblebee communities. Their predictions for bumblebees are dire.
Are Carpenter Bees Endangered?
Carpenter bees are not on the Endangered Species list, but you might think that the greatest threat they face is the humans who work to exterminate them. These bees burrow into dead wood and can cause structural damage to homes, so they are not as highly regarded as honey bees or bumblebees.
But like many solitary bees, a bigger threat for Carpenter bees is the class of pesticides known as neonicotinoids. Neonicotinoids are absorbed by the entire plant, so when bees forage among flowers that have been treated with them, the nectar and pollen they carry to their nests will likely contain these toxins. Because neonicotinoids are used in 120 countries throughout the world, they can potentially have a harmful effect on large populations of bees.
What Other Species of Bees Are Endangered?
In 2016, after a 10-year study by a collective group of state agencies, independent researchers, and the Xerces Society, the U.S. placed seven species of Hawaiian yellow-faced bees on the Endangered Species list. These species have experienced a pronounced decline in number due to loss of habitat, natural disasters, land-use changes, and invasive species – both plants and pests:
- Hylaeus anthracinus
- Hylaeus longiceps
- Hylaeus assimulans
- Hylaeus facilis
- Hylaeus hilaris
- Hylaeus kuakea
- Hylaeus mana
It is thought that human development is the primary reason these bees are threatened.
Then, in 2017, the Rusty Patched bumblebee (Bombus affinis), was also added to the list. Habitat loss and threats from pests and pathogens are what has caused its decline. Since the 1990s, Bombus affinis has decreased by 88% in the number of populations.
What Role Does Disease Play in the Decline of Bees?
The disease can affect both adult bees and their developing broods. The most common diseases faced by adult bees include chronic bee paralysis (CPV), acute bee paralysis (APV), and Nosema disease, which primarily affects honey bees by invading their digestive tracts. Common brood diseases are those that are caused by a spore-forming bacterium or fungus-like American foulbrood, European foulbrood, Chalkbrood, and a virus known as Sacbrood.
But the reason disease is such a big problem is that it is often spread to native bee populations when bees are imported to help with pollination. Due to a worldwide decline in pollinators, honey bees and bumblebees are often shipped into regions that are in need of pollination services for crops.
Unfortunately, because of the absence of laws that require health checks, some of the imported bees are infected with diseases that eventually spread to native bee populations. Even when bee shippers do look for diseases, they often focus only on honey bee pathogens, and neglect to consider diseases specific to bumblebees.
While there is not much research that shows how prevalent this problem is or how virulent the diseases are, one group of university students in Australia discovered that a common honey bee disease was transmitted by flowers and resulted in the deaths of many wild Australian bees.
Shipping of managed bees can also be a problem even if those bees are healthy. Introducing imported bee species can cause native populations to become stressed, and thus more susceptible to disease.
What Causes Bees to Become Endangered?
It’s a combination of factors that contribute to the decline of bees, although some of the causes have proven to be greater threats than others.
Habitat Loss
Habitat loss is widely considered to be the greatest threat to bees, due to changes in land use for commercial agriculture and urban development. When land is cleared to grow monocultures (one kind of crop instead of many different ones), bees are no longer able to forage among a diverse range of plants, and that can affect their nutrition.
Modern farming methods also require changes in natural structures like waterways, trees, and meadows in order to scale commercial crop production. Although urban development is also a threat, city planners can require that parks and verge plantings be added to make up for the loss of resources when the land is cleared.
Pesticides
The commercial agriculture industry is also the culprit for the widespread use of pesticides – especially the aforementioned neonicotinoids that can threaten bee colonies when bees forage among treated plants.
In early 2020, the Environmental Protection Agency proposed some interim steps that may help cut down on the damage caused by this class of pesticides. A couple of the proposed changes include:
- Managing ways to keep these pesticides only on plants that absolutely require them and to reduce the amount used on at-risk crops.
- Restrictions on the timing of application so that bees would be less exposed when crops are blooming.
It’s not clear if these proposals are simply suggestions or will eventually become mandates.
Climate Change
As discussed earlier, increasingly hot temperatures are contributing to the decline of several bumblebee species. But it is not only hot temperatures that can threaten bees’ livelihoods. Changing weather patterns can affect when plants bloom, and if bloom time doesn’t coincide with when bees emerge from hibernation, bees will not be able to collect the pollen and nectar they need to feed their colonies and keep them alive.
Parasite, Diseases, and Predators
The deadly varroa mite is not the only parasite bees face. In honey bee colonies, there is another mite that can invade the bees’ breathing tubes. Parasites and diseases can often be controlled with managed bees, but once diseases spread into wild populations, nothing can be done to mitigate the disaster.
Predators also threaten bees, but it’s important to note that bees are a part of the food chain. Some larger animals do feed on bees, and that’s just a natural process of the ecosystem. However, when invasive species are introduced – especially highly aggressive ones like the newly discovered “murder hornets – the result can be particularly destructive for bee populations.
Invasive Species
Invasive bee species can affect native bee populations when they take over habitats and force the native bees to compete for foraging resources. But invasive plant species can also harm bees when they crowd out some of the native plants and diminish foraging diversity. Bees need to forage among a diverse array of floral resources in order to get balanced nutrition.
German researcher, Benjamin Kaluza, said “Only in environments rich in plant species do bees find continuously sufficient, balanced and high-quality food and other resources.”
Are Bees Becoming Extinct?
Although it may seem like a hopeless situation for non-managed bees, some policy changes – like bans on particular pesticides – can help alleviate the crisis to some extent. Additionally, the Pollinator Partnership Action Plan, which was established in 2016 to dedicate land to pollinators, is still intact – although it is not certain if it will continue past 2020.
Currently, the USDA is studying ways to control pathogens and parasites, and that work can greatly contribute to the health of bees.
But for the average citizen, the best way to take an active role in helping bees to survive is to plant native wildflowers, rely less on pesticides, and consider replacing even a portion of the lawn with a garden full of food and habitat resources for native bees. It may not seem like a big contribution, but if many within our society would take these small steps, our collective actions could be truly meaningful.
