Saturday, June 8, 2013

The Magically Disappearing Honeybee and You

Would you notice anything if honeybees disappeared? What about if large amounts of flowering plants started disappearing? And now fruits and vegetables like peaches, peas, pears, and watermelons. Without the western honeybee Apis mellifera L. many of our foods would vanish, and our diets would suffer. The food pyramid we have would crumble; other goods like fiber, drugs, and fuel would become scarce. Despite building the honeybee to be the forefront of pollination on many monocrop plantations world wide (Mazer 2007) it is incredibly fragile susceptible to externalities that we have created.

Apis Mellifera (Public Domain)

But is this doomsday event ever likely to occur? I mean we can have our cake, or in this case fruit, and eat it too right? Sadly, the unfortunate scenario can become a reality. Because A. mellifera L. is the premier biotic pollinator for agricultural crops world wide (
Delaplane and Mayer, 2000), the effects of a disappearing honeybee is a reality. Figure 2-1 from Status of Pollinators shows a decline in managed honeybee colonies in the US. Since 1945, we have seen a loss of around 4 million bee colonies (USDA-NASS).
Figure 2-1: Total U.S. Colonies from 1945-2005 

Some of the potential causes for this decline have come from a variety of factors: parasitic mites, pathogens, pesticides, transgenic crops, migratory beekeeping, lack of genetic diversity, and invasive species. These biotic and abiotic factors are possible reasons for colony collapse disorder (CCD), which is the phenomenon where entire honeybee colonies abruptly disappear. These culprits have been identified, but not publicized enough.

The Varroa Mite (Varroa destructor) has been a major threat to colonies. These mites have caused a significant decline in populations of honeybees throughout the world (Jong, 1990; Sammataro et al., 2000). In some states, around 30-80 percent of managed colonies were lost due to these mites in 2003, despite the reliance on pesticides. (Elzen et al., 1998).  However, a certain pathogen proves to be more harmful than this deadly mite
The most harmful pathogen to honeybees is Paenibacillus larvae. By attacking honeybees during their larval stage of metamorphosis, the bacterium spreads the contagious disease American foulbrood (AFB) not only within managed colonies, but between managed colonies through the use of spores. The disease is so serious that most states require that if a colony is found to host AFB, it should be destroyed and its equipment, like the physical colony, be burned or buried. (Ratnieks, 1992).

The use of pesticides has also negatively affected honeybee populations. The major cause for the decline has been from improper use of pesticides, specifically neonicotinoid pesticides like acetamiprid, clothianidin, and imidacloprid. (Johansen and Mayer, 1990). After spraying agricultural fields, bees visit flowers for their pollen and nectar, and return to their hive to store this pesticide-soaked pollen and nectar. This pesticide is a neurotoxin, which affects a bee’s behavior. In fact, the European Union recently installed a ban on these types of pesticides because of their high risk to bees. What the EU, and many other people worry about with pesticide use, are colonies being exposed in their foraging environment and in their colonies. This pesticide-covered pollen is fed to honeybee larvae and stored in the form of the honey. Over time, the whole colony will become exposed to this pesticide, which may affect every individual in the hive.

Genetically modified organisms have also been a concern, as there has been some evidence that the insecticidal proteins in pollen can negatively affect honeybees, even though they are not the target species. (Losey et al., 1999) These pollen grains are fed to young brood by nursing honeybees, which potentially alters behavior during the adult stage of the bee’s life. 

The problems associated with migratory beekeeping are the stressful environments bees are placed in. Typically, farmers rent beehives from commercial beekeepers. These hives are placed on a truck and driven thousands of miles to their farms. Even though they have access to lots of pollen in these new areas, they are not used to a new location every 3 months since they only swarm once a year (Mazer, 2007). Managed colonies are not subject to the highly selective breeding process that natural colonies endure because inbreeding depression has made many managed colonies weaker than their natural counterparts. Not only is there a reduction in diversity between managed colonies, but within managed colonies. Because of this, many colonies are susceptible to hereditable diseases and infectious diseases (Mazer, 2007)

There is also the concern of invasive species. The Africanized honeybee (A. mellifera scutellata) was first introduced in Brazil in 1960s, and was later spotted in Texas in 1990, and California in 2000 (Hunter et al., 1993). These species not only have been responsible for depleting resources and increasing competition for honeybees, but attacking managed colonies and killing its queen.

Knowing all this, the potential loss of managed and unmanaged honeybee colonies could have severe economic consequences. It’s estimated that 30% of all food humans consume is made possible from honeybees. Dennis vanEngelsdorp, state apiarist for Pennsylvania's Department of Agriculture, shows us what would be missing from our plate if bees were not here. The, “one in three bites of food,” we eat would be gone if it wasn’t for bees. 

Crop pollination is also estimated to be valued at $16 billion dollars when only examining the United States’ agricultural industry.  Other important crops that need pollinating are alfalfa and clover, which are important food sources for livestock feed. Other important products that honeybees produce are honey, which has a value of $150 million annually. It’s an understatement to say that the loss of honeybees will be catastrophic to the agricultural industry. (Mazer, 2007)

But what can be more severe than this? Well, the loss of plant diversity could be drastic as well. The mutualistic association between honeybees and plants is extremely important for the reproduction of angiosperms. We would see drastic reductions in plant diversity without essential supporting ecosystem services like pollination (Mazer 2007). From this many mutualistic relationships that animals have with flowering plants will be disrupted, and other species could suffer as well. The effects of this could undermine the agricultural system we have established, which would leave many individuals and organisms without food. Without the honeybee, we will experience a global catastrophe resulting in countless innocent lives being lost.

Knowing all this, what can we do? Well, individual action is a start, but global action is necessary to reverse these effects.  You can help by starting your own beehive in your backyard. Honeybees are actually quite friendly, and will not bother you at all when they’re foraging. You can also stop using pesticides around your home, to protect insect visitors from neurotoxins. Talk to your neighbors as well, and work with them to reduce their pesticide use too. You can also begin writing to your government officials, asking them to consider a ban on certain pesticides in the state to protect honeybees. Having a garden that flowers throughout the seasons helps too, as it gives an area for honeybees to forage throughout the year. The sooner action is taken to protect honeybees, the better off we, and other organisms, will be.


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