Data from: Context-dependent expression of the foraging gene in field colonies of ants: the interacting roles of age, environment and task

Task allocation among social insect workers is an ideal framework for
studying the molecular mechanisms underlying behavioural plasticity
because workers of similar genotype adopt different behavioural
phenotypes. Elegant laboratory studies have pioneered this effort, but
field studies involving the genetic regulation of task allocation are
rare. Here, we investigate the expression of the foraging gene in
harvester ant workers from five age- and task-related groups in a natural
population, and we experimentally test how exposure to light affects
foraging expression in brood workers and foragers. Results from our field
study show that the regulation of the foraging gene in harvester ants
occurs at two time scales: levels of foraging mRNA are associated with
ontogenetic changes over weeks in worker age, location and task, and there
are significant daily oscillations in foraging expression in foragers. The
temporal dissection of foraging expression reveals that gene expression
changes in foragers occur across a scale of hours and the level of
expression is predicted by activity rhythms: foragers have high levels of
foraging mRNA during daylight hours when they are most active outside the
nests. In the experimental study, we find complex interactions in foraging
expression between task behaviour and light exposure. Oscillations occur
in foragers following experimental exposure to 13 L : 11 D (LD)
conditions, but not in brood workers under similar conditions. No
significant differences were seen in foraging expression over time in
either task in 24 h dark (DD) conditions. Interestingly, the expression of
foraging in both undisturbed field and experimentally treated foragers is
also significantly correlated with the expression of the circadian clock
gene, cycle. Our results provide evidence that the regulation of this gene
is context-dependent and associated with both ontogenetic and daily
behavioural plasticity in field colonies of harvester ants. Our results
underscore the importance of assaying temporal patterns in behavioural
gene expression and suggest that gene regulation is an integral mechanism
associated with behavioural plasticity in harvester ants.