Key Points:
- Researchers propose new model for the evolution of higher brain functions and behaviors in insects.
- Kenyon cells in the mushroom bodies of “primitive” sawflies and sophisticated honey bees were compared.
- Findings could help better understand the evolution of higher brain functions and behaviors in humans.
Insects may be small, but their brains can tell us a lot about the evolution of our own. A team of researchers from the University of Tokyo and Japan’s National Agriculture and Food Research Organization (NARO) has proposed a new model for the evolution of higher brain functions and behaviors in the Hymenoptera order of insects, which includes bees, wasps, and ants.
The team studied the Kenyon cells in the mushroom bodies of sawflies and honey bees, which are important for learning, memory, and sensory integration. The study found that the honey bee brain had evolved to have three different types of Kenyon cells that had evolved from one multifunctional ancestor Kenyon cell subtype.
The researchers used a range of techniques, including transcriptome analysis, to identify the gene expression profiles of the various Kenyon cell subtypes and speculate on their functions. They found that the three Kenyon cell subtypes in honey bees showed comparable similarity to the single Kenyon cell subtype in sawflies. As the number of Kenyon cell subtypes increased, each subtype inherited some distinct properties from the ancestral Kenyon cell, resulting in their present-day functions.
Despite the differences in the size and complexity of insect and mammalian brains, there are similarities in function and the basic architecture of the nervous system. The model proposed in this study for the evolution and diversification of Kenyon cell subtypes may help towards better understanding the evolution of our own behavior.
Takayoshi Kuwabara, doctoral student and lead author from the Graduate School of Science, said that there are many mysteries about the neural basis that controls social behavior, whether in insects, animals or humans, and how it has evolved still remains largely unknown. The researchers are now interested in studying the Kenyon cell types acquired in parallel with social behaviors, such as the honey bee’s “waggle dance.”
The study was published in Science Advances and supported by Grant-in-Aid for Scientific Research (B) 20H03300 and Grant-in-Aid for JSPS Fellows 21J20847.
In summary, the research into the evolution of higher brain functions and behaviors in insects could provide valuable insights into the development of our own brains.
