Bees and Socialization
The National Institute of Mental Health (NIMH) interviewed Dr. Gene Robinson about his recent research on bees and socialization and asks these questions: What is the most altruistic animal? What can we learn from the small, but complex bees?
Introduction: Welcome to "Speaking of Science." The National Institute of Mental Health presents a series of conversations with innovative researchers working in a wide range of disciplines to pave the way for the prevention, recovery, and cure of mental illness.
Dr. Wang: Good morning. Dr. Robinson, thank you. It's a pleasure to have you here for NIMH Director's Innovation Speaker Series and I'd just like to introduce you. His groundbreaking on the regulation of social behavior using honeybees spans and integrates a wide range of disciplines: neuroscience, genomics, molecular biology, behavior and evolutionary biology. And what I found most remarkable is that you somehow managed to find a time to mentor well over a hundred junior faculty, post docs, graduate and undergraduate students. It's really quite remarkable. So welcome. It's really a pleasure for us.
Dr. Robinson: Thank you. It's a pleasure to be here.
Dr. Wang: Why did you choose honeybees, and why did you choose particular species?
Dr. Robinson: Well honeybees are an excellent species for these kinds of studies of genes, brains, and social behavior, because they have been the best-studied social insect. The reason for that is that they have provided humans with products that humans value. So honeybees have provided honey, and honey is the world's oldest sweetener. People have been paying attention to honeybees for a long time. There's a tremendous amount known of the behavior of honeybees. That knowledge then forms the foundation for our research program. So we know how bees behave in a variety of different circumstances, because it's been important to people for very pragmatic reasons to know that. That's also led them, of course, to a bee keeping industry. And in the beekeeping industry, they have developed techniques of manipulation that we can then use in our scientific enterprise, such as for example instrumentally inseminating queens to be able to control genetics, a great tool that we have queens to be able to control genetics, a great tool that we have that is not available for other social insects.
Dr. Wang: In broad terms, what are we learning?
Dr. Robinson: Well, in broad terms I think we two insights so far. First of all that the genome is very responsive to the social environment. When we experimentally perturb the social environment in ways that are biologically natural, we see strong responses on the part of the genome in neurons in particular brain regions. So the genome is very responsive to changes in the social environment is the first insight. And this insight by the way now has been seen in a variety of other animals, vertebrate animals, and there are strong indications of that it's humans as well. And then the second insight is more of an evolutionary one. And that is that social behavior, which arguably has evolved later than many forms of solitary behavior, or in evolutionary terms it's more derived relative to solitary behavior, that various forms of social behavior have evolved by changing the functions of some genes that are involved in solitary behavior.
Dr. Wang: What about bees' orientation flights? I'm particularly intrigued by those. How do they relate to bees and learning, and what does this tell us about human memory and learning?
Dr. Robinson: Well, we tracked orientation flights with radar a few years ago, and got some very interesting insights. First I'll just give you the background. So I mentioned before that bees when they're young, they work in the hive, then they graduate and they become foragers. So when they're foragers, they go out. They collect food from hundreds of flowers on any given trip. They cover miles of flight. When they have collected a full load of food, they make, pardon the pun,a beeline back to the hive. What that means is that they know their environment. They have learned where they live. They know their address. They know where they live relative to prominent landmarks in the environment. They use that to navigate, to make their way home. They then use that to communicate. They are the only animal outside of humans that has a symbolic language. They communicate distance, direction, and quality of the food that they have just collected to their hive mates. To do that they have to know, again, where they live. So how do they get that information? They take orientation flights. So before they become foragers, while they are still doing jobs inside the hive, they take little breaks here and there, and take flights that are orientation flights.
Dr. Wang: What's the connection between the bees' use of dance to communicate and dopamine, our well-known reward chemical?
Dr. Robinson: When a solitary animal comes across food, the better the food, the more they will eat. When a honeybee comes across food, the better the food, the more she will go back home and dance. Honeybees are the ultimate, altruistic, cooperative species. Everything that they do is for the good of the hive. The reward system is very, very labile. It can be coupled to other forms of behavior. So the same brain region is involved in modulating and mediating a variety of different behaviors. It's easily coupled with other behaviors. We're seeing something very similar in our work on dance language and dopamine in honeybees. The dopamine treatment which gives animals more pleasure -- a variety of animals -- makes bees dance more. So it's as if dancing more is more pleasurable to bees. So the way we are interpreting this is in a evolutionary context. Somehow there's been a switch from me to we. And so the behavioral systems that support selfish behavior, eating, that are tuned by a reward system, are now tuned to provide a cooperative behavior.
Dr. Wang: How did the social interactions that you are referring then affect or alter gene expression? What does this tell us about the ecoplasticity?
Dr. Robinson: These kinds of experiments where we've manipulated the social environment -- I'll give you one example in a moment -- are the kind of experiments that we've used to make that kind of broad generalization of how dynamic the genome is to social input. So for example I mentioned that when there is a shortage of foragers, some bees will grow up more quickly, and become precocious foragers. The stimuli associated with those changes, the kinds of social signals that are involved are social signals that cause changes in brain gene expression, that then cause the bee to grow up more quickly. So for example, insects go in for chemical communication in a big way, pheromones, animal perfumes if you will that cause changes in behavior. Honeybees have a variety of these pheromones. One pheromone is produced by the queen, and it has the opposite effect. It causes bees to slow down how fast they grow up. It delays maturation. We find when we expose bees to this pheromone produced by the queen, and then measure brain gene expression, we see a massive response. Thousands of genes are regulated in response to the queen's pheromone, and in a very predictable way. So if the queen's pheromone delays the onset of foraging, what we see is that genes that are associated with working in the hive, the hive jobs are up-regulated. Genes that are associated with foraging are down-regulated in the brain.
Dr. Wang: What have your findings taught us about the evolution of social behavior?
Dr. Robinson: I think what we're looking at is the idea of a sort of a leggo-like approach or a modular approach. There are particular modules that are involved in particular neural functions. Those modules can be put together in different ways to create more complex behavior, such as social behavior.
Dr. Wang: Dr. Robinson this is very innovative and exciting research, and it's been a pleasure talking to you.
Dr. Robinson: Thank you. Thank you very much for your interest.
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