Genetic Differences in Scouting vs. Non-Scouting Bees

An article in Medical News Today, features a study on honey bees and genetic variations between scouting bees and non-scouting bees. Bees that are considered to be scouting bees are females that go out and search for food all on their own, never being told where to go. When they find one, they fly back to their colony and perform what is known as the "waggle dance" to relay the message of the new food source to the rest of the bees.

Scientists conducted an experiment to test the genetic differences between scouting and non-scouting, or foragers. The did this by enclosing bee hives in a large mesh cage so the bees could not escape and placing a specific food source outside of the hives, letting the bees get used to it. A couple days later, a new food source was added to the enclosed area in different locations than the original food source. Researchers observed which bees found the food source first and painted a colored dot on them to keep track of them.

The process of adding a new food source and marking the bees was done two more times so some bees had three dots on them. Researchers then separated the scouting bees from the non-scouting bees. Bees with two or more dots on them were considered to be scouting bees. Then, the brains were taken from the captured bees and geneticists examined the differences between gene expression between the two types of bees.

What they found was extremely interesting; 16% of the 7,500 genes in honey bees were significantly different in the two. Some include genes that regulate neurotransmitter receptors of glutamate and dopamine. Even more interesting, when non-scouting bees were treated with octopamine, a chemical that activates the dopamine receptor, they started showing behavior similar to scout bees. Alternatively, when a scout bee was given a glutamate inhibitor, it would act like a forager.