Honeybee Predators – Varroa Mites

Honeybee predators are a serious threat not just to the honeybees but also to our ecosystem and ultimately to us humans.

The honeybee has been around for centuries and is a vital part of our ecosystem. They play an important role in pollinating plants, which helps to produce fruits and vegetables. Unfortunately, honeybees are facing several threats that could lead to their extinction and humans are one of the threats!

Varroa Mite

One of the biggest predators of honeybees is the varroa mite that can reproduce only in a honeybee colony. Originally from Asia, the varroa mite was introduced to Europe and the US during the 80´s.

Scientists believe that the parasites came over from Asia on honeybee colonies that were imported for pollination. Once they arrived, they spread rapidly and has become a major problem for beekeepers. Since then, the parasites have spread to all continents.

Appearance

The mite is reddish brown, oval-shaped and about 1/16th of an inch long. It attaches itself to bees and their brood, feeding on their fat body and hemolymph (blood), often killing the bee.

Researchers believed for decades that varroa mites feed on blood, however, new research at the University of Maryland suggests that the mites feed on the fat body of bees. The fat body of a bee can be compared to the human liver, although it also stores food and contributes to the immune system. This weakens the bees and makes them more susceptible to disease.

Study leader Samuel Ramsey said,

¨ Bee researchers often refer to three Ps: parasites, pesticides and poor nutrition. Many studies have shown that varroa is the biggest issue. But when compromised by varroa, colonies are also more susceptible to the other two. Now that we know that the fat body is varroa’s target, this connection is now much more obvious. Losing fat body tissue impairs a bee’s ability to detoxify pesticides and robs them of vital food stores. The fat body is absolutely essential to honey bee survival.”

 

Life Cycle of the Varroa Mite

One or two days before a brood cell is capped, the female mite enters it and lays about 1 egg per day after 60 hours. The first egg laid is a male, and subsequent eggs are female.

Depending on the sex of the mite, the eggs take between three to nine days to mature. Whereas honeybee worker brood cells remain capped for about 12 days, those of the drones remain capped for 15 days. The additional time inside the cell could explain why mites prefer drone over worker cells. It is thought that the varroa mite is attracted to the scent of drone larvae because they can raise more mites per cell than they can in worker brood.

Breeding Preferences

Researchers have detected varroa mites two to 30 times more often in drone brood than in those of workers. Not surprising, given that the extra time within the cell means drone cells yield 2.4 mites, while the worker cells only yield 1.7 mites on average.

The mites reproduce rapidly, causing tremendous stress on the colony, making the bees highly susceptible to viruses. As a result, the entire colony can be wiped out within a couple of seasons.

How do Varroa Mites Spread?

The mites spread viruses and disease amongst their hive population and other hives if two bees cross in pollination. They can also spread by traveling on clothing or equipment, or they can be carried in the air and spread through wind currents.

Signs of Varroa Mite Infestation

Varroa mites are thought to be one of the main reasons why honeybee populations have declined in recent years. They are most active during the summer months when temperatures are warm. Given that the growth of varroa mites is exponential means that the mites increase slowly at first. Colonies with low infestation usually show very few symptoms. Although as the mite increase in numbers, the symptoms are more apparent. It can take three to four years to detect an infection in the hive.

A heavily infected hive causes crippled and crawling honey bees, scattered brood, a lower rate of return to the colony after foraging, impaired flight performance, a significantly reduced weight of worker bees, and a reduced lifespan. The symptoms, known as the parasitic mite syndrome, are abnormal brood patterns, sunken and chewed cappings and larvae fallen in the bottom or side of the cell. As a result, the honeybee population declines, the queen is replaced and the colony eventually breaks down and dies.

Beekeepers should constantly monitor and inspect their colonies, especially drone brood for signs of mite infestations and take quick action if they find evidence of any presence.

Pesticides

Pesticides are another big threat to honeybees. Many pesticides are toxic to bees, and even trace amounts can be deadly. When bees come into contact with pesticides, it can affect their navigation, learning, and memory. They also damage the bees’ nervous system and impair their ability to find their way back to the hive. Pesticides also make bees more susceptible to diseases.

Studies have found that neonicotinoid pesticides, which are the most widely used class of pesticides in the world, can kill honeybees outright and make them more susceptible to pests and diseases. Other studies have found that pesticides can make honeybees more susceptible to parasites and diseases, which can lead to colony collapse. Pesticides can also contaminate pollen and nectar, which honeybees rely on for food.

Loss of Habitat

Humans are mainly responsible for the two most prominent causes that lead to the decline of bees, namely pesticides and loss of habitat. As humans continue to develop land, there is less available for honeybees to build their hives and forage. But it is not only destroying their habitat that leads to a decline of the worldwide bee population.

Every year industrial agriculture converts grasslands and forests into mono-culture farmlands that are heavily contaminated with pesticides to produce maximum yield. Add a drought or heavy rain, air pollution, climate change and extremely low frequency electromagnetic fields to the loss of habitat and the decline becomes even more serious.

Solutions

There are a few things we can do to help protect honeybees from these threats. One is to plant native flowers and plants that bees can use for food. Another is to avoid using pesticides in our gardens and yards. We can also help by supporting organizations that are working to protect honeybees and their habitats.

By working together we can help ensure that honeybees continue to play a vital role in our ecosystem for years to come. Some common sense solutions are requesting to ban dangerous pesticides, protecting and preserving wild habitats and restoring ecological agriculture.

What other ways can we help protect honeybees? Let us know in the comments below!