How do you find the newest, trendiest restaurants with the best food in your neighborhood (that is, of course, during non-pandemic times when restaurants are all open)? Well, one way that you may notice the new hip spot is to follow the crowds. If you wander by a spot filled with folks enjoying mouth-wateringly delicious food, you will likely be drawn to visit that restaurant yourself. But, how does your brain process these signals about food resources and quality? Tianfei Peng and two of his colleagues from the University of Mainz in Germany dug into this question by looking at the inner-workings of a slightly simpler brain – that of the stingless bee – to uncover the brain's role in social animal foraging.
The trio suspected that the compound octopamine could play a role in how both individuals and social groups find food and perceive its value. Octopamine is a major player in the brain function of invertebrate animals, including many insects, equivalent to the fight-or-flight hormone noradrenaline in vertebrates, including humans. Past research highlighted the key role of octopamine in the ability of individual honey bees to learn about food resources and to communicate that information to their buddies. Like honey bees, stingless bees live in colonies that are characterized by strict division of labor and unwavering cooperation, yet the stingless bees’ ancestors diverged from their honey bee cousins over 80 million years ago. Could octopamine also stimulate individual and social foraging behaviors in stingless bees?
Peng and colleagues tested this idea in wild colonies of the Brazilian stingless bee (Plebeia droryana). To get the bees foraging, they set up feeders close to each colony filled with tasty sugar syrup. Once the bees had learned to snack at the feeders, the researchers dosed the syrup with octopamine, to test their theory that bees would feed more and in bigger groups when they experimentally boosted this important brain compound.
And they were right. Individual foraging increased almost 75% following an octopamine-laced treat. Although past studies show that octopamine has lightning-fast impacts on social foraging in honey bees (detectable in a matter of minutes), the stingless bees took a bit longer to follow their friends to the feeders and it took more than 2 h for the team to detect larger groups at the feeder after the insects had consumed octopamine. So, although stingless bees are a bit slower to jump on the octopamine wagon, the effects of the hormone on their behavior are undeniably similar to those of their honey bee cousins, despite millions of years of diverging evolution.
The researchers suggest that these octopamine-induced changes in the response to food may be driven by the brain's perception of food value and the potential rewards at different food patches. If the brain perceives a food resource as rewarding, insects are more likely to return to it again and again, bringing their friends along on subsequent visits. There is a still a huge amount to learn about how the brain shapes stingless bee behaviors and particularly how octopamine interacts with other brain hormones to regulate important daily tasks like sleeping, learning, aggression and social interactions. But when it comes to feeding, octopamine seems right for increasing a bee's appetite.
