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’.

Human socio-cultural evolution in light of evolutionary transitions: introduction to the theme issue

“…While many bee species are solitary, some species are eusocial, where the entire colony functions much like a single individual [27]. Keasar et al [26] hypothesize that learning to exploit complex flowers would be more common in eusocial than in solitary species, and its likelihood would increase with increasing colony size and colony longevity. They construct a mathematical model to test these hypotheses, and their results are non-trivial.…”

“…Here, three papers address aspects that are common to ETIs in general. Keasar et al [26] study the role of learning in honeybees. While many bee species are solitary, some species are eusocial, where the entire colony functions much like a single individual [27].…”

Connecting and integrating cooperation within and between species

“…When they are unrelated or of different species, such information sharing could still come about through direct reciprocity or fitness interdependence (sharing information in some situations can also be costly to the individual being eavesdropped upon [35], a situation we do not consider here). Bumblebees, for example, are well documented to observe and thereby learn how to handle complex flowers from other individuals-a time-consuming process but one that increases handling proficiency and colony-level food intake [36]. Moving away from social insects, certain bats learn the location and quality of fruits from others, including their mothers [37], and seed-dispersing birds follow other members of their flock to newly located fruit crops [38].…”