Africanized Honeybees in the United States: A Growing Concern
The Africanized honeybee, often referred to as the “killer bee,” is an invasive species in the United States, with a particularly strong presence in the state of Arizona. While Africanized honeybees are similar to European honeybees in many ways, they exhibit significant differences in behavior, resilience, and potential danger to humans and animals. Approximately to 95 to 100 percent of Feral honeybee colonies in the Phoenix and Tucson areas of Arizona consist of Africanized honeybees. Africanized honeybees are a beneficial insect due to their ability as a very good pollinator. This blog post explores the history, life cycle, dangers, and survival strategies of Africanized honeybees, particularly in Arizona, where they have become a noteworthy environmental and public safety concern.
The Arrival of Africanized Honeybees in the U.S.
Africanized honeybees first arrived in the United States in 1990. These bees are a hybrid of the African honeybee (Apis mellifera scutellata) and various European honeybee subspecies, such as the Italian honeybee (Apis mellifera ligustica). The African bees were initially imported into Brazil in the 1950s as part of an experiment to improve honey production in tropical climates. However, they escaped quarantine and spread rapidly across South America.
In 1990, the first Africanized honeybees crossed into the United States through Texas. From there, they spread quickly across the Southwest, including Arizona, where the warm desert climate is ideal for their survival and proliferation. By the early 2000s, Africanized honeybees had established a significant presence in the southern parts of the U.S., including Florida, California, New Mexico, and Texas and have continued to expand their range in the years since.
Danger to Humans and Animals
One of the most significant concerns with Africanized honeybees is their highly defensive behavior when they think their hive is threatened. While European honeybees typically only sting humans or animals in self-defense or when their hive is threatened, Africanized honeybees are much more defensive and quicker to react to disturbances. Africanized bees are far more likely to sting in larger numbers if they perceive any threat, even from something as minor as a person walking too close to a hive. They are highly protective of their hive, and their tendency to chase perceived threats for longer distances makes them more dangerous.
The risks to humans and animals are particularly high for those who may be allergic to bee stings, as their tendance to sting in large numbers can result in dozens or even hundreds of stings in a short amount of time. Though bee stings are not usually lethal, an allergic reaction can lead to severe anaphylactic shock, which can be fatal without immediate medical treatment. For pets, particularly dogs and especially horses, encounters with Africanized bees can also result in multiple stings, leading to serious injury or even death.
Life Cycle and Differences from European Honeybees
The life cycle of Africanized honeybees is similar to that of European honeybees, with three primary stages: egg, larva, and pupa, before emerging as adult bees. Queen bees lay eggs that hatch into larvae, which are then fed by worker bees until they develop into pupae and eventually become adult bees. This process typically takes about three weeks for worker bees, but it can vary depending on environmental conditions.
However, Africanized honeybees differ from European honeybees in a few key aspects. One notable difference is the rapid reproduction rate of Africanized honeybees. Queen Africanized bees tend to lay more eggs compared to European queen bees, allowing their colonies to grow and multiply more quickly. This rapid expansion allows Africanized honeybees to spread faster and build larger hives, which in turn increases their chances of surviving in the wild.
Another difference lies in their behavior. While European honeybees are generally docile and can be managed with relative ease, Africanized honeybees are more prone to aggressive defense of their hives. This defensive nature is linked to their greater sensitivity to disturbances and their tendency to swarm in response to threats.
Resistance to the Varroa Destructor Mite
One of the biggest threats to honeybee populations worldwide is the Varroa destructor mite, a parasitic mite that attacks and weakens honeybee colonies by feeding on their blood and spreading virus, bacteria, and fungi. The Varroa mite is a rusty-red color and is visible with the naked eye as it hitchhikes on honeybees. Varroa mites have devastated European honeybee populations, leading to colony collapse in many regions.
Africanized honeybees, however, exhibit a remarkable resistance to the Varroa destructor mite. Their natural resistance is believed to be a result of their African ancestry, as African honeybees have developed behaviors that limit the mite’s ability to reproduce. For instance, Africanized honeybees engage in grooming behaviors that help remove mites from their bodies, and they may also exhibit quicker colony turnover, which disrupts the mite’s reproductive cycle.
This resistance is not absolute, and nearly all Africanized honeybees in Arizona still have some level of Varroa mite infestation. This trait has allowed Africanized honeybees to thrive in regions where Varroa mites are prevalent, giving them an advantage over other honeybee species.
Swarming Behavior and Differences from European Honeybees
A honeybee “swarm” is a group of bees that leave an established colony to form a new colony. Swarming is a natural part of a honeybee colony’s reproduction process. Africanized honeybees, however, swarm more frequently than European honeybees. While European and Africanized honeybees mainly swarm during the spring or early summer as part of their reproductive cycle, Africanized bees can swarm at any time of the year, especially when they perceive a threat or are overcrowded.
Conclusion
Africanized honeybees have established themselves as a significant presence in the United States, especially in regions like Arizona, where their rapid spread and aggressive nature pose serious concerns for public safety. They are a very good pollinator and therefore a beneficial insect. Their resistance to the Varroa destructor mite, combined with their faster reproductive rate and more frequent swarming behavior, make them both a boon and a challenge for beekeepers and researchers alike. Understanding these bees’ life cycle and behavior is essential for mitigating the risks they pose to humans and animals. While Africanized honeybees are not inherently more dangerous than their European cousins, their heightened aggression and defensive tendencies make them a species that requires careful attention and respect. To prevent danger to humans and pets, Africanized honeybees should be removed when they establish their hives close to homes and businesses.