The Science of Nature

, 106:49 | Cite as

Brain differences between social castes precede group formation in a primitively eusocial bee

  • Sarah Pahlke
  • Sarah Jaumann
  • Marc A. Seid
  • Adam R. SmithEmail author
Short Communication


Social interactions may shape brain development. In primitively eusocial insects, the mushroom body (MB), an area of the brain associated with sensory integration and learning, is larger in queens than in workers. This may reflect a strategy of neural investment in queens or it may be a plastic response to social interactions in the nest. Here, we show that nest foundresses—the reproductive females who will become queens but are solitary until their first workers are born—have larger MBs than workers in the primitively eusocial sweat bee Augochlorella aurata. Whole brain size and optic lobe size do not differ between the two groups, but foundresses also have larger antennal lobes than workers. This shows that increased neural investment in MBs precedes social group formation. Larger MBs among foundresses may reflect the increased larval nutrition provisioned to future queens and the lack of social aggression from a dominant queen upon adult emergence.


Social evolution Social brain hypothesis Neural plasticity Dominance Mushroom body 


Funding information

This work was supported by NSF grant #17-1028536545 to ARS and MAS.

Compliance with ethical standards

Ethical approval

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.George Washington UniversityWashingtonUSA
  2. 2.Program in NeurobiologyUniversity of ScrantonScrantonUSA

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