Metabolic rate shapes phenotypic covariance among physiological, behavioral, and life history traits in honeybees

Metabolic rate is often cited as the fundamental rate that determines the
rate of all biological processes by shaping energetic availability for the
various behavioral and life history traits that contribute to performance.
It has therefore been suggested that metabolic rate drives the widely
observed covariance among these different levels of phenotypic traits.
However, much of the work on this topic has relied on pairwise
correlational analysis, thereby leaving an important gap in our
understanding regarding the functional links that shape this phenotypic
covariance, often referred to as pace-of-life. Using honeybees as an
experimental model, we measured a large number of behavioral, life history
and physiological traits in individual bees and used a structural equation
model to characterize the phenotypic covariance structure among these
traits. Following this with a path analysis, we demonstrate that variation
in metabolic rate plays a fundamental proximate role in driving this
phenotypic covariance structure in honeybees. We discuss the importance of
these findings in the context of how interindividual variation in terms of
slow-fast phenotypes may drive the phenotype of a group and the functional
role metabolic rate might play in shaping division of labor and social
evolution.