Octopamine (OA) and juvenile hormone (JH) are implicated in the regulation of age-based division of labor in the honeybee, Apis mellifera. We tested the hypothesis that these two neuroendocrine signals influence task-associated plasticity in circadian and diurnal rhythms, and in brain expression of the clock gene period (per). Treatment with OA, OA antagonist (epinastine), or both, did not affect the age at onset of circadian rhythmicity or the free running period in constant darkness (DD). Young bees orally treated with OA in light-dark (LD) illumination regime for 6 days followed by DD showed reduced alpha (the period between the daily onset and offset of activity) during the first 4 days in LD and the first 4 days in DD. Oral treatment with OA, epinastine, or both, but not manipulations of JH levels, caused increased average daily levels and aberrant patterns of brain per mRNA oscillation in young bees. These results suggest that OA and JH do not influence the development or function of the central pacemaker but rather that OA influences the brain expression of a clock gene and characteristics of locomotor behavior that are not thought to be under direct control of the circadian pacemaker.
|Original language||American English|
|Number of pages||19|
|Journal||Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology|
|State||Published - Feb 2007|
Bibliographical noteFunding Information:
Acknowledgments We thank RaW Nir and Allan Ross for expert assistance with bees; Mira Cohen, Rachel Saf, and Sara O’Brien for technical assistance in the laboratory; Bryan A. White for gracious use of the ABI 5700 real-time PCR machine. Thanks to Gene E. Robinson for support, helpful discussions, and for reading an earlier version of this manuscript, Joseph P. Sullivan for performing the allaetectomy operations, Dave J. Schulz for performing HPLC analyses for biogenic amine levels, and two anonymous reviewers for helpful comments on a previous version of this manuscript. Financial support was provided by NIH grant GM57196 to GER, the National Institute for Psychobiology in Israel grant number 036.7207 to GB, and the Israel–US Binational Science Foundation # 2001022 to GB and GER.
- Circadian rhythms
- Clock gene
- Honey bee
- Juvenile hormone
- Locomotor behavior