Causes

When examining die off in bee population whether it be domesticated bees or wild/feral bees one has to be careful to know the difference between periodic die off and die off on an endangered scale. Bee die off is finally getting attention from the press, but when a large influx of hype is created around a subject, researchers must be wary of the truth being stretched in published work. Many articles do not specify the difference between domesticated and wild, and address decline in bee population as a problem for all bees. While domesticated bee population has been a problem many times, the population has actually recently hit a boom. On the other hand, native and wild bees are experiencing an unprecedented decline in population.

All over the United States Beekeeping has become a hobby of many people in both rural and urban areas. This spike in interest in beekeeping has done wonders for the domesticated honey bee population. Even though many diseases and certain aspects of climate change affect these bees the increase in interest and people who own hives counters this. Periodically a large amount of the population of domesticated bees is wiped out by disease, however after each influx of disease the population grows back to an even larger size than before. This normal process should not be interpreted as domesticated bees becoming endangered.

On the other hand recent studies have shown that while domesticated bees are in good shape the same cannot be said for wild bees. Many factors are causing the decline in population of wild bees in the United states. The main causes are outlined below.

Pesticides

It's a given that pesticides are harmful to living organisms. However, until recently researchers did not realize that these harmful chemicals could be killing bees as well. Farmers by no means intentionally kill bees, they are in fact pollinators for some of their crops. Despite this, recent studies have shown the harmful effects pesticides have on bees, particularly wild ones.

The most harmful of pesticides to bees are Neonicotinoid pesticides. These are the most commonly used pesticides in the world (Bee Decline & Pesticide Use) There are many effects on bees that can cause entire colonies to collapse. These effects include but are not limited to:

Compromised immune response
Shortened adult life cycles
Impaired memory and learning
Reduced social communication (reduces foraging efficacy)
Disorientation, which also impairs foraging
Delayed larval development and disrupted brood cycle
“Gut” microbe disruption, leading to malnutrition

This can all be caused even in small doses of Neonicotinoid pesticides. (Bees In Crisis). The effects of these pesticides are greatly contributing to the decline in population of wild bees and is also killing domesticated bees.

Habitat Loss

All living organisms require a habitat to survive and thrive. We see organizations campaigning against the habitat loss that is happening in places like the Amazon. However, people when speaking about habitat loss do not normally think of insects. Unlike domesticated bees, wild bees are in decline because of habitat loss. "Intensification of agriculture prompts the loss and fragmentation of valuable natural to semi-natural perennial habitats for pollinators, such as agroforestry systems, grasslands, old fields, shrublands, forests, and hedgerows." (Causes). A lack of habitat for bees to live and gather resources in causes colonies to become extremely weak. Bee colonies need resources in order to thrive because so many organisms have to be supported. Their resource hubs are being replaced by sprawling farmland and industry. Without plants close to hives bees have to fly farther for pollination and many times do not gather enough resources for the hive. Bees are affected by habitat loss the same as any animal, more attention needs to be paid to these irreplaceable pillars of the ecosystem.

Parasites and Pathogens

Bees like all other living organisms are prone to harmful parasites and pathogens. In bees these parasites and pathogens can wipe out entire colonies with ease. With all of the other causes of die out, wild bees are even more susceptible to parasites and pathogens. These parasites and pathogens generally come in waves wiping out large amounts of bees, but the bees still recover. However, when combined with habitat loss, pesticides, and climate change, wild bee populations are unable to recover properly. Currently the main parasite plaguing bee hives is Veroa Mite. This mite weakens bees immune systems and makes them prone to other diseases which can collapse the hive. This mite can be managed in domesticated bee hives through treatment but in wild bees there is no control of the mite. The exposure to other diseases means that bees are dying off at a rapid rate.

Climate Change

Climate change is the silent killer of the bee population because its effects are harder to track. Bees like other living organisms adapt to change in their enviorments. Usually these changes are slow and give the bees time to adapt. However, climate change is changing bees' environments at a rate that the bees cannot keep up with. With the seasons lengths rapidly changing because of climate change, bees do not know when to come out of winter hibernation. This means that the flowers could bloom before the bees even become active again. Bees would be unable to find sufficient resources to support the colony. In addition, climate change itself weakens the colony because slight increases in temperature can be detrimental for bees. Several experiments have been done to test how bees react to warmer temperatures in their hives and almost every time the colony collapses. (Bee Populations Dying Climate Change Global). Overall, climate change heightens the effects of all the other causes, and leads to bees unable to survive.