When we think of honeybees, we usually associate them with pollination and honey. With such fuzzy, cumbersome bodies, it is hard to take them seriously. That is, until one is trapped in close vicinity to our person. Then their proximity is quite alarming. But other than that, when was the last time you ever thought carefully about how much bees affect our lives?
by Areana Park | staff writer | SQ Vol. 10 (2012-2013)
Background
With closer examination, it becomes apparent that the work of honeybees is extremely important within human society. The honey that they create is used as natural flavoring and sweeteners in our food, whether eaten directly or applied in our cooking. Honey is regarded by nutritionists as a “perfect protein” because of its molecular structure, and contains many medicinal properties that are effective in treating a wide range of maladies from sore throats to diabetic ulcers.
But perhaps most importantly, honeybees work hard to help plants continue their cycle of growth with pollination, making them essential to human food production. It makes sense that honeybees are very important to our economy, health and future scientific discoveries. Unfortunately, due to a variety of reasons, the healthy of honeybee colonies has slowly declined.
Dr. James Nieh, Vice Chair of UC San Diego’s Division of Biology’s Section of Ecology, Behavior, and Evolution, has conducted important research on honeybee health and was able to find an important correlation between the effect of pesticides and the negative way in which these pesticides affect honeybee behavior and communication.
Key Communication
Scientifically, the honeybee colony is an interesting system to study. Honeybees have a sophisticated yet simple communication system within their colony. They are one of few insects that have a highly evolved and complex social life. Like humans, honeybees are extremely social creatures with highly evolved representational communication. A good example of one of these types of evolved communication is the waggle dance. When food is scarce, worker bees (who are all female) communicate the location of a quality food source through recruitment. A worker bee recruits its nest mates by communicating the location of a potential high quality food sources by implementing a waggle dance, an incredible communication system that maps out the source of potential food through movements. The waggle dance is just one of the ways honeybees relay information, but how they obtain the information of the location of high quality food sources is extremely important to the well-being of their colony.
Honeybee Decline
Unfortunately, over the past decade, honeybee colonies have slowly collapsed and numbers have declined. Though this decline is due to a number of reasons, one of the causes is due to the negative effects of pesticide on honeybee behavior. We use pesticides in our crops to get rid of pests and harmful insects, but in doing so we often harm the insects that help the harvest, like the honeybee.
Imidacloprid, an important component of many pesticides, was found to have a direct affect on honeybee foraging behavior. Dr. James Nieh has studied honeybee behavior and the effect of imidacloprid extensively.
With careful research and experimentation, Dr. Nieh found that pesticides negatively affect honeybee behavior on a molecular level and cause dysfunctional behavior that affects the well being of the entire colony.
Picky Eaters
“The most amusing and also admirable thing about bees, for me, is their tenacity at getting a job done. A forager will often continue to forage at a food source non-stop, despite inclement conditions,” Dr. Nieh said.
So what happens when something interferes with that tireless and motivated behavior? Through extensive experiments, Dr. Nieh was able to study the effects of imidacloprid on honeybee behavior.
“Imidacloprid blocks the nicotinic acetylcholine receptor, which is found on insects like the honeybee, leading to its cascade of effects in honeybee behavior. It is a key ingredient in many insecticides and in high doses can be lethal,” he explained.
Dr. Nieh tested the effects of imidacloprid on learning and memory in bees. The purpose of his experiments was to find out whether or not it would affect a bee’s ability to measure distance, perceive quality of a sugar solution, and communicate that information to the rest of the colony.
This discernment of quality in sugar or “sucrose responsiveness” (SR) plays a role in how forager bees divide their labor. Within the colony, foragers specialize in nectar while others specialize in collecting pollen or water. Depending on their role in the colony, bees will have a certain standard for the concentration of sugar that they expect in their food source.
“Foragers specializing in collecting nectar will, not surprisingly, have developed a sweet tooth and will not extend their proboscis, or mouthparts, to accept low concentration sugar solutions. On the other hand, foragers that collect pollen or water would accept very low concentrations of sugar,” said Dr. Nieh.
