BioProject

Honey bees move through a series of in-hive tasks (“nursing”) to outside tasks (“foraging”) that coincident with an intense increase in metabolic activity. Social context can cause worker bees to speed up, or slow down this process and foragers may revert back to their earlier in hive tasks accompanied by reversion to earlier physiological states. To determine if the transcriptional profile of forager bees can revert, or if the effects of flight on gene expression are irreversible, we used whole-genome microarrays. Brain tissue and flight muscle exhibited independent patterns of expression during behavioral transitions, with patterns of expression in the brain reflecting both age and behavior, while flight muscle exhibited primarily age-related patterns of expression. Our data suggest that the transition from little to no flight (nurse) to intense flight (forager), rather than the amount of flight has a major effect on gene expression. Following behavioral reversion there was a partial reversion in gene expression but some aspects of forager expression patterns, such as those for genes involved in immune function, remained. These data suggest an epigenetic control and energy balance role in honey bee functional senescence. Overall design: Brains and thoraces from the same individuals of all behavioral groups were compared on a total of 132 arrays. The samples were hybridized against each other using a loop design. The groups tested are outlined as follows: Typical aged nurse 'YN' (8-10 days old; <1 day flight experience), Precocious forager 'PF' (8 to 10 days old; 2 to 3 days flight experience), Overaged nurse 'ON' (19 to 22 days old; < 1 day flight experience), Forager - low flight 'TFL' (19 to 22 days old; 2 to 3 days flight experience), Forager - high flight 'TFH' ( 19 to 22 days old; 7 to 9 days flight experience), Forager - old 'OF' (25 to 26 days old; 10 to 12 days flight experience), Reverted nurse 'RN' (25 to 26 days old; 7 to 9 days flight experience). The comparisons are outlined as follows: YN:ON (6 arrays), ON:RN (6 arrays), RN:TFH (6 arrays), TFH:TFL (6 arrays), TFL:PF (6 arrays), PF:YN (6 arrays), ON:TFL (12 arrays), YN:OF (6 arrays), OF:RN (6 arrays), RN:YN (6 arrays). Each comparison was done for individual brains and thoraces. Total: 132 arrays