Abstract
Reproductive and worker division of labour (DOL) is a hallmark of social insect societies. Despite a long-standing interest in worker DOL, the molecular mechanisms regulating this process have only been investigated in detail in honey bees, and little is known about the regulatory mechanisms operating in other social insects. In the fire ant Solenopsis invicta, one of the most studied ant species, workers are permanently sterile and the tasks performed are modulated by the worker's internal state (age and size) and the outside environment (social environment), which potentially includes the effect of the queen presence through chemical communication via pheromones. However, the molecular mechanisms underpinning these processes are unknown. Using a whole-genome microarray platform, we characterized the molecular basis for worker DOL and we explored how a drastic change in the social environment (i.e. the sudden loss of the queen) affects global gene expression patterns of worker ants. We identified numerous genes differentially expressed between foraging and nonforaging workers in queenright colonies. With a few exceptions, these genes appear to be distinct from those involved in DOL in bees and wasps. Interestingly, after the queen was removed, foraging workers were no longer distinct from nonforaging workers at the transcriptomic level. Furthermore, few expression differences were detected between queenright and queenless workers when we did not consider the task performed. Thus, the social condition of the colony (queenless vs. queenright) appears to impact the molecular pathways underlying worker task performance, providing strong evidence for social regulation of DOL in S. invicta.
Original language | English |
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Pages (from-to) | 660-672 |
Number of pages | 13 |
Journal | Molecular Ecology |
Volume | 23 |
Issue number | 3 |
Early online date | 22 Jan 2014 |
DOIs | |
Publication status | Published - Feb 2014 |
Bibliographical note
AcknowledgementsThe authors would like to thank Sarah Kocher (Harvard) and Naomi Altman (Penn State) for assistance with the statistical analysis and Mark Brown, Elli Leadbeater, members of the Brown group and the three anonymous reviewers for providing thoughtful comments that helped improving the quality of the manuscript. The authors would also like to thank Alex McMenamin for performing the qRT‐PCR studies. Many thanks to Craig Praul and his team at the Penn State Genomics Core Facility for performing all the steps to prepare RNA samples for microarrays and for providing assistance during RNA extraction and data analysis. A special thanks to Eileen Carroll, Chin‐Cheng Yang (Scotty) and all the undergraduate research assistants in the Shoemaker Lab that provided extraordinary support, help and advice during field work and laboratory experiments at the USDA‐ARS, CMAVE in Gainesville, Florida. This study was funded by US Department of Agriculture AFRI Award 2009‐35302‐05301 to DS, CMG and John Wang (Academia Sinica), the Swiss NSF and an ERC advanced grant to LK and by the Société Académique Vaudoise to CL.
Keywords
- division of labour
- fire ants
- foraging workers
- microarrays
- queen pheromone
- sociogenomics
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Fabio Manfredini
Person: Academic