Can sociality facilitate learning of complex tasks? Lessons from bees and flowers

Abstract

The emergence of animal societies is a major evolutionary transition, but its implications for learning-dependent innovations are insufficiently understood. Bees, with lifestyles ranging from solitary to eusocial, are ideal models for exploring social evolution. Here, we ask how and why bees may acquire a new 'technology', foraging on morphologically complex flowers, and whether eusociality facilitates this technological shift. We consider 'complex' flowers that produce high food rewards but are difficult to access, versus 'simple' flowers offering easily accessible yet lower rewards. Complex flowers are less profitable than simple flowers to naive bees but become more rewarding after a learning period. We model how social bees optimally choose between simple and complex flowers over time, to maximize their colony's food balance. The model predicts no effect of colony size on the bees' flower choices. More foraging on complex flowers is predicted as colony longevity, its proportion of foragers, individual longevity and learning ability increase. Of these traits, only long-lived colonies and abundant foragers characterize eusocial bees. Thus, we predict that eusociality supports, but is not mandatory for, learning to exploit complex flowers. A re-analysis of a large published dataset of bee-flower interactions supports these conclusions. We discuss parallels between the evolution of insect sociality and other major transitions that provide scaffolds for learning innovations. This article is part of the theme issue 'Human socio-cultural evolution in light of evolutionary transitions'.

Keywords: eusociality; evolutionary transition; flower morphology; learning; pollination.

Figure 1.

The optimal allocation of foragers to complex flowers for varying time horizons (colony longevity). The arrows indicate the end of the time horizon for the different values of T.

Figure 2.

The optimal number of foragers on complex flowers for varying proportion of foragers in the colony (1 − r).

Figure 3.

The optimal allocation of foraging effort on complex flowers for varying colony sizes (N).

Figure 4.

The optimal number of foragers on complex flowers at varying learning rates β.

Figure 5.

The optimal number of foragers on complex flowers at varying probabilities of forager survival (=individual lifespan).