Tuesday, October 11, 2011

The Unanswered Question of Bee Domestication

This article is one big paraphrase of a paper I wrote for a class I took with Mark Feinstein at Hampshire College called Cognition in Domesticated Animals. I highly recommend to course to anyone. For the sake of the audience, I have cut down the length of the original paper. However I have also added extra information on domestication in order to contextualize some of the information. Although my notebook for the class is over three thousand miles away in Massachusetts, I'll try my best. If there are any glaring problems with this article, please contact me. I have also maintained all of the citations in case you are interested in reading more about this topic. Where information was added, I included the link, or the full citation in the text.

Bees communicate the location of flowers and food by "dancing". Wikipedia now has a great, well cited article on this behavior. This was first noted by the Austrian scientist Karl von Frisch in his book Die Tanzsprache der Bienen (English: The Dance Language and Orientation of Bees). Today our understanding of how bees communicate through "dancing" is much more complex.

15,000 year old cave painting
found in Valencia, Spain.
Humans and bees have always coexisted. Before beekeeping, hunter-gathers would climb trees in order to retrieve honey from nests. Wall paintings showing this behavior have been found in different geographical locations, such as Zimbabwe, China, and Spain; which suggests that the way, and means by which people collected honey from bees developed at the same time in different places. One wall painting in Spain shows how humans would put giant ladders against trees in order to climb up and collect the honey. In Thailand permanent ladders made out of bamboo would be installed into the trees in order to access the honey bees’ nests (Oldroyd 213).

As a result, the art of beekeeping also has developed at the same time in different places. In Vietnam, Apis Dorsata honeybees were kept in rafters. African tribes would, and still do create artificial “hives” out of suspended wood logs, which could be placed near a dwelling. Hieroglyphics show us that the Egyptians kept hives in clay pots, as did the Greeks. In the seventeenth century the Greeks started using wicker hives. The Romans had a more advanced hive made of wicker, oak and dung. Wen the Romans invaded Britton, the practice spread there too.

Aristotle was one of the first people to write about the inner workings of beehives, which is fascinating considering a clay hive wouldn’t allow such observations. The Romans were the first to develop transparent hives from lantern horn, or mirror stone. In fact it was the Romans who first started the practice of beekeeping. The word apiary, a place in which bees are kept, is Latin for beehive; the root word apis is bee (Free 78 - 112). Virgil too wrote concerning bees and where to place apiaries. While he made many significant findings, some of the concepts of the hive were beyond him. For example, while he noticed that there was a class structure within a bees nest, he called the queen bee a king; he also remarked that pollen stuck to bees in order to act as a ballast for when they flew. Some countries today such as Oman and Yemen still refer to the Queen Bee as a sheik, meaning they consider it a male (Free 100).

One of the theories that have been suggested as an explanation to dog domestication is that of self domestication. That is, dogs that had a smaller flight distance would eat food scraps from neolithic "garbage dumps" humans were making. This reduce in flight distance may be the result of an altered state of brain chemistry, which in turn would effect other behaviors. For example, the size of a domesticated dog's skull and brain is on average, smaller than their wild type (Serpell, James (1995). The Domestic Dog; its evolution, behaviour and interactions with people. Cambridge: Cambridge Univ. Press. p. 35. ). This theory also suggests that humans, and animals are participating in a reciprocal relationship in which they both benefit.

For example:
This strange link between coat color and temperament stems from a relationship between pigment production, hormones, and neurochemistry. It is not the case that coat color causes a difference in temperament, but rather that certain physiological processes underlie facets of both coat color and behavior. In particular, the hormones and neurotransmitters involved in the stress response and other behaviors are closely integrated with pigment production.
For example, the neurotransmitter dopamine and the hormones noradrenaline and adrenaline, which are involved in the stress response, have the same biochemical precursor as the melanin pigments (Anonymous 1971, Ferry and Zimmerman 1964). In addition, dopamine directly influences pigment production by binding to the pigment-producing cells (Burchill et al. 1986). Dopamine indirectly influences pigment production by inhibiting pituitary melanotropin, also known as melanocyte stimulating hormone (MSH), which is responsible for stimulating pigment cells to produce pigment (Tilders and Smelik 1978).
Therefore, by breeding only the most docile animals in a group, humans select for physiological changes in the animal's hormonal and neurochemical systems, changes that impact morphology and physiology -- including fur color. A change in fur color during domestication may therefore be an incidental byproduct of selection for tameness.
It is therefore suggested that tamed animals have less melanin production:

The character Mongo riding a tame, mostly white bull in the film Blazing Saddles.
 The question of domestication for bees is a tough for a variety of reasons. Do they fit classification for domestication? Honey bees cannot exist without the hive. The word eusocial has been used to describe their complex hierarchical behavior, and the beehive has been described as operating as a “super organism". Due to the beehive existing as a single organism, and early man’s misconception as to how bees mated, it was tough for one to directly or artificially select for the right honey bees due to the fact that so many of their behavioral traits are linked to social interaction (Menzel 27).

When European settlers came to North America they brought with them the European Honey Bee. While this is the species of bee we are familiar with in North America, it is specifically the Italian honey bee, Apis Mellifer that now populates the continent. This species was not introduced into North America until 1859. It has been suggested by sources that the Italian honey bee was selected out of all the honey bees for a verity of reasons (Frank, et el.; 2000).  They occupy less space in the nest, they swarm even less than other honey bee species, they are more adaptable to climate, and most importantly, they produce more honey than other honey bee species (Frank, et el.; 2000).

On the other hand these verities of bees were most likely first selected because their honey was edible. Texture, color, and a final product that is free of brood are all important factors when selling honey (Free, 124). Some wasps, such as the polistinae wasp (paper wasp) produce honey that can be poisonous to humans. These wasps are eusocial and also form hexagonal combs (Strassman). Although, one study on the nutrients in wasp honey notes that wasp honey has been collected for human consumption in the past (Hunt, et el; 1998). There is evidence however that those wasps produce poisonous honey by harvesting pollen from specific plants, such as the datura plant, which themselves are poisonous to humans (Ramirez, et al; 1990). Why this situation would not occur in honey bees is of interest. Do honey bees collect pollen from datura plants? If they do, what causes their honey to not have an adverse affect on humans?

Today beekeepers are able to select for desired traits by removing larva from their cells in the hive and placing them in “queen cups” where they can then be introduced into another colony. As mentioned before, there are many aspects to control for. “Cleaning behavior” which is the removing of damaged larva, and debris from the nest. Grooming is also important; this is the removing of mites from the bees themselves. A foreign mite introduced from another bee species has the potential to wipe out a whole race of bees. Bees stealing honey from other hives is another behavior that one beekeeper reports, and supposedly can be controlled for (Cushman).

By having apiaries, are domestic bees receiving any benefit from humans through this relationship? That is, besides any causalities taken when the honey is taken to be processed, and at least in a majority of western countries; we do not consume the bees. A recent phenomenon called colony collapse disorder is when European honey bees disappear. One has to wonder what role humans may have in this situation. Everything from pesticides to cell phone radiation has been suggested as the cause. Oldroyd suggested that it may be a combination of factors which are worsened by the presence of mites which lower the immune system of the bees (Oldroyd; 2007). If it is not too late, bees will have to be selected based on their immunity to these adverse conditions.

Nest size is another factor that may have been selected for in bees. Considering more bees mean more honey, solitary bees are never used for honey cultivation. A healthy honey bee nest can have anywhere from 50,000 to 60,000 bees (World Book Encyclopedia; 154 - 161). Compare to a paper wasp nest, which can house around 5,000 wasps (Strassman). Due to the fact the nests are smaller and wasps are carnivores, they do not produce as much honey as a honey bee. Wasps also construct their nests out of paper instead of wax, which is less useful for human consumption.

A bee on a yellow Rudbeckia hirta flower.
The pain score for honey bees on several different scales tends to fall in the middle. On the Starr Sting Scale of Pain, insects in the Apidae genus all score a two on a scale of one to four (Starr; 1985). On the Schmidt Sting Pain Index honey bees once again score a two out of four; alongside yellow jackets and wasps. The paper wasp scores a four on the Schmidt scale. However honey bees are less aggressive than wasps. This could have to do with the fact that honey bees consume nectar, while wasps are carnivores and therefore have to hunt and fight to survive. (Online sources suggest that the bee stinger has evolved through fighting between bees, however all of these sites cite an outsourced Wikipedia article). Have honey bees been selected based on the pain of their sting, or is this a trait that is tied to domestication?

The Africanized honey bee for example may have adapted its aggressive behavior from having to protect their nests from predators in their environment; possums, bears, badgers, jackals and other predators that would destroy their nest. The climate of Africa also means that the Africanized bees are more tailored to harsher climate with less water. Due to this reason, Africanized bees have been able to easily travel outside of their habitat, much to the discontent of the people who come into contact with them. Beekeepers in Brazil have successfully been able to breed Africanized bees into their apiaries and over time, select for less aggression (Tew). The only major difference between Africanized bee and honey bees is that the Africanized bees are more aggressive, and will pursue a perceived threat for a longer distance (Tew).

The worker honey bee’s brain contains about 850,000 cells, half of which belong to the occipital lobe (Menzel 191 - 201). Vision is incredibly important for bees, and they can see ultraviolet light. There is no current research suggesting that honey bees have smaller brains than their “wild” counterparts. However as stated before, due to the large size of honey bee nests, the honey bee must exhibit many social behaviors. For example, the bees do a very good job of regulating themselves. At some point all the drones from a nest will be escorted out to leave (Free 44). While this behavior may seem bizarre, it assures that the drones are able to continue spreading their genes. Oldroyd compares bee reproduction to an arms race (114). One has to wonder if there ever has been a practice of simply killing the drones. Perhaps there are drones, or have been drones that are not “charismatic” enough to leave the nest alive.

Nevertheless it seems that, compared to their wild types, the “domestic” bees are much more ductile. Comparison of the brain size and density of honey bees to wasps and their Africanized counterparts would prove to be interesting. Studying the hormonal balance of the two might also prove valuable. All in all bees are incredibly smart creatures that can distinguish flowers, communicate through their movement, and possibly create mental maps of the areas around hives (Menzel). To the naked eye there are no noticeable physical differences or phenotypes between “domestic” bees and their wild type.

Right now there may not be much physical evidence of the bee being domesticated, even though many important traits still have been selected for over time; aggressiveness, quality of honey, amount of honey produced, wax production, and efficiency. In the future it will be important to select for traits that make bees more resistant to disease spread by mites as well as ourselves. Nonetheless more research needs to be done in this field; research should one the brain size of honey bees species, as well as their counterparts; to see if they indeed fall in line with the criteria set by domestication. Still one cannot deny the rich evolutionary history of the bee, spanning over almost every continent, climate, and many taxonomies (Menzel, 8).

Sources:
"Bee." World Book Encyclopedia. Vol. 2. Chicago: Feild Enterprises Educational Corporation, 1973. 154-61. Print.

Cushman, Dave. "Honey Bee Colony Assessment Criteria." Beekeeping & Bee Breeding. 10 May 2005. Web. 9 May 2011. <http://www.dave-cushman.net/bee/assessmentcriteria.html>.

Frank, P., L. Garnery, G. Celebrano, M. Solignac, and J.-M. Cornuet. "Hybrid Origins of Honeybees from Italy (Apis Mellifera Ligustica) and Sicily (A. M. Sicula)." Molecular Ecology 9.7 (2000): 907-21. Print.

Free, John B. Bees and Mankind. London: Allen and Unwin, 1982. Print.

Hunt, James H., Anthony M. Rossi, Nels J. Holmberg, Samuel R. Smith, and William R. Sherman. "Nutrients in Social Wasp Honey." Physiology, Biochemistry and Toxicology 91.4 (1998). < http://www.umsl.edu/~huntj/Number%2064.pdf >.

Menzel, Randolf, and Alison Mercer. Neurobiology and Behaviour of Honeybees. Berlin. Springer, 1987. Print.

Oldroyd, Benjamin P. (2007). "What's Killing American Honey Bees?". PLoS Biology 5 (6): <http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1892840.>

Oldroyd, Benjamin P., Siriwat Wongsiri, and Thomas D. Seeley. "Asian Honey Bees: Biology, Conservation, and Human Interactions." Harvard University Press. Print.

Ramirez, M., E. Rivera, and C. Ereuc. "Fifteen Cases of Atropine Poisoning after Honey Ingestion." Vetinary and Human Toxicology 41.1 (1999): 19-20. Print.

Starr, Christopher K. "Pain Scale for Field Comparison of Hymenopteran Stings." Journal of Entomology 20.2 (1985): 225-32. Web. 10 May 2011. <http://www.ckstarr.net/cks/1985-PAIN.pdf>.

Strassmann, Joan E. "Social Behavior of Polistine Wasps." Rice University Web. Rice University, 1 Nov. 2006. Web. 9 May 2011. <http://www.ruf.rice.edu/~evolve/Waspweb/wasphome.html>.

Tew, James E. "Africanized Honey." Ohioline. Ohio State University. Web. 9 May 2011. <http://ohioline.osu.edu/hyg-fact/2000/2124.html>.

2 comments:

  1. Fuck bees, i'm allergic to their sting hahaha no bees for me sir.

    ReplyDelete
  2. I don't like them either. I have this fear they're gonna enter my ear.
    I'm not even kidding. :D

    ReplyDelete