This is a three-semester-long endeavor, where I will come up with my own research project, carry this project out, and ultimately defend my thesis in front of the University of Maryland Honor Board. As of now, May 2017, I am finishing up the first part of this process: developing my own research project.
Learning and memory in honey bees is vitally important to a colony’s health. Honey bees depend on their ability to learn and remember landmarks and celestial cues in order to find their way to and from food sources. When bees return to the colony after foraging, they must remember detailed information about food sources so they can communicate this information to other foragers.
At first it may seem like a challenge to quantify a honey bee’s ability to learn and retain information. However, in 1961, Kimihisa Takeda developed a method to do just this. Takeda’s method is called Proboscis Extension Response (PER) conditioning. PER is a method of classical conditioning that can be used to assess the learning ability and memory retention of honey bees. Under normal circumstances, if a drop of sucrose solution is touched to a bee’s antenna, it will reflexively extend its proboscis. Below is a video I took of the bees responding to the sucrose solution with proboscis extension. PER takes this behavior and pairs it with an odor stimulus, so that the bee will learn to associate extending its proboscis with the odor, and not with the sucrose solution. The bee’s ability to make this connection is used as an indicator of its ability to learn.
Research using PER shows that sub-lethal doses of several pesticides actually decrease honey bees’ learning ability and memory retention. One of these pesticides is Fluvalinate. Fluvalinate is a varroa treatment that is applied to a colony in the form of strips. This means that it potentially comes into contact with bees of many different ages. While there is already extensive research on Fluvalinate’s effects on PER performance, there is no research on how the age of the bee at the time of exposure impacts the intensity of those effects. That is what I’m trying to tackle in my research project.
Basically, I’m going collect a lot of newly emerged bees and keep them in several small populations (~30 bees), in modified solo cup cages. Different cups will be exposed to Fluvalinate at different ages. Some will be exposed when the bees are 5 days old, some when they are 10 days old, and some when they are 15 days old. These 3 ages roughly represent 3 worker roles in the colony. Five day old bees are pre-nurses, that clean cells and cap brood, 10 day old bees are nurses, that feed larvae, and 15 day old are foragers, than collect pollen and nectar for the colony.
What I’m expecting to see after conditioning is that fewer bees are able to make the correlation between the odor and the sucrose stimulus if they have been exposed to the fluvalinate, regardless of the age when they were exposed. I’m also expecting to see less bees successfully conditioned in the groups that were exposed later in life, as past research indicates that pesticide sensitivity increases with age.
My project is going to take a lot of intricate planning if I’m going to complete it all in the upcoming fall semester (which is my goal). But as complicated as it may be, I can’t wait to get started and learn a lot more about honey bees and the methods with which to study them.