INVICTA2 · Caste-specific gene expression in the fire ant, Solenopsis invicta
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2007-08-01 → 2009-07-31
- EU contribution
- €174,398
- Participants
- 1
- Scheme
- EIF
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Results in brief
Final Activity Report Summary - INVICTA2 (Caste-specific gene expression in the fire ant, Solenopsis invicta)
Colonies of the single-queen-per-colony social form of the invasive fire ant, solenopsis invicta, are typically specialised in the production of a single sex, i.e. virgin queens versus males, during the reproductive season. Queens determine the sex of their eggs by fertilising or not fertilising them. The first are destined to become female, i.e. workers or virgin queens, while the latter become males. It has previously been shown that a colonys final sex allocation ratio, i.e. the energy invested in virgin queens versus males, is mainly determined by the proportion of female eggs laid by the mother queen. It has recently become clear that queens have a strong influence over the caste fate of her daughters, i.e. over whether her female eggs will develop into virgin queens or small, medium or large size workers. Our main aim was to identify genes whose expression pattern, either up or down regulated, in queens could explain the observed variation between queens in primary sex ratio. Using powerful microarray technology we compared the expression of more than 22 000 genes between 30 solenopsis invicta mother queens with widely varying primary sex ratios. We identified a previously unknown neurotransmitter receptor, whose expression was significantly, highly (with R2 equal to 0.81) and positively correlated with the proportion of female eggs laid by a mother queen. This result, which we were pursuing further by the time of the project completion, was potentially of great importance for the study of adaptive between and within species variation in sex ratios in any ant species. It suggested that it might be possible to experimentally change the sex ratio produced by captive ant colonies by adding synthetic neurotransmitters to their food.
Data: CORDIS, © European Union
Project objective
Societies of ants, bees, and wasps achieve a highly efficient division of labour by matching the morphology, physiology, life-history, and behaviour of each female to her role in the colony. Females thus occur in distinct castes (e.g. workers and queens). Castes are an example of polyphenism: the caste fate of developing larvae does not depend on their genotype, but is determined by their environment. Therefore, caste differentiation must involve the differential expression of genes that are shared by all castes. Identifying caste-specific patterns of gene expression thus offers a special opportunity to study the generation of adaptive morphological variation by a fundamental biological process, and is the key to profound understanding of the evolution of sociality. Because of the recent development of new methods (especially microarrays) for identifying differentially expressed genes, a burst of research on caste differentiation is predicted. I propose to study caste-specific gene expression in the fire ant, Solenopsis invicta, with a large ( and gt;20,000 clones) spotted cDNA microarray that was recently developed, sequenced, and annotated at the prospective host institute, the group of Prof. L. Keller at the University of Lausanne. S. invicta is the second social insect species (after the honeybee) and the first ant species for which a large microarray has become available. I will study differential gene expression at three levels: in queen vs. worker larvae; in minor vs. major worker larvae; and in the brai n of (equally old) foragers and brood care workers.
Original text from CORDIS.
Participants
- UNIVERSITE DE LAUSANNE · LAUSANNECoordinatorSwitzerland
Links
Data: CORDIS, © European Union