Chennai, December 10, 2011: A honey bee colony "has to make decisions constantly," said Dr. Thomas Seeley, Professor and Chairman in the Department of Neurobiology and Behavior at Cornell University, Ithaca, New York, during an interview (Podcast dated December 9, 2011) by Sarah Crespi, Senior Web Editor, Science Magazine, talking about the research being undertaken by his team at the Cornell University. He clarified further: "Every day, for example, it has to make the decision of where its foragers should go foraging - which patches of flowers are the best ones? ... It also has to make other decisions, such as whether or not to build more combs, which is the infrastructure in which the whole colony functions. And a key feature of all these decisions, is the fact that they are distributed, or it's a collective, decision-making. ... these are decisions that have to be worked out collectively by the worker bees in a honey bee colony."
Collective decision making has to be worked out collectively, for example, by scout bees searching for a suitable nest site for a swarm to settle. In this process, the groups of scout bees compete for their choice of hive sites and the group with majority numbers of bees silencing the opponents, much like the neurons in the mammalian brains. Seeley and his team found that an inhibitory signal between bees advocating different locations allows them to make a decision even when potential nest sites are equally favorable. In their paper* published on December 8, 2011 in the issue of Science, the researchers explain the design of experiments and their findings. Following is the Press Release dated December 8, 2011 by the Cornell University, on this research.
*Seeley, T.D., Visscher, P.K., Schlegel, T., Hogan, P.M., Franks, N.R. and Marshall, J.A.R. 2011. Stop signals provide cross inhibition in collective decision-making by honeybee swarms. Science, 8 December 2011, DOI: 10.1126/science.1210361
CORNELL UNIVERSITY PRESS RELEASE
Cornell University, Thursday, Dec. 8, 2011
Bee swarms mimic human brain neurons to make decisions
Ithaca, N.Y. - Swarms of bees and brain neurons make decisions using strikingly similar mechanisms, reports a new study in the Dec. 9 issue of Science.
In previous work, Cornell University biologist Thomas Seeley clarified how scout bees in a honeybee swarm perform "waggle dances" to prompt other scout bees to inspect a promising site that has been found.
In the new study, Seeley, a professor of neurobiology and behavior, reports with five colleagues in the United States and the United Kingdom that scout bees also use inhibitory "stop signals" - a short buzz delivered with a head butt to the dancer - to inhibit the waggle dance produced by scouts advertising competing sites. The strength of the inhibition produced by each group of scouts is proportional to the group's size. This inhibitory signaling helps ensure that only one of the sites is chosen. This is especially important for reaching a decision when two sites are equally good, Seeley said.
Previous research has shown that bees use stop signals to warn nest-mates about such dangers as attacks at a food source. However, this is the first study to show the use of stop signals in house-hunting decisions.
Such use of stop signals in decision making is "analogous to how the nervous system works in complex brains," said Seeley. "The brain has similar cross inhibitory signaling between neurons in decision-making circuits."
Co-authors Patrick Hogan and James Marshall of the University of Sheffield in the United Kingdom explored the implications of the bees' cross-inhibitory signaling by modeling their collective decision-making process. Their analysis showed that stop signaling helps bees to break deadlocks between two equally good sites and to avoid costly dithering.
The study was funded by the Cornell Agricultural Experiment Station, the Univrersity of California-Riverside and the U.K. Biotechnology and Biological Sciences Research Council.