Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: This year 12 polymorphic co-dominant microsatellite or simple sequence repeat (SSR) DNA markers were developed specifically for Camponotus pennsylvanicus. These markers will be used with the maternal mitochondrial DNA (mtDNA) sequence markers already in use to determine the intra- and interspecific genetic structure for these insects. Because the markers are co-dominant both the maternal and paternal contributions to the genetic structure can be determined. Furthermore, the mtDNA markers are being used with agonism assays to validate ant site fidelity. Ants representing different colonies are put into an arena. If they fight they are considered to be from different colonies. Since the colonies from which the ants were taken the previous year were known, and since the mtDNA fingerprint was also determined upon initial collection, each ant's mtDNA haplotype should be the same if there is continuous site fidelity. We discovered that the ant colonies remain site specific and the ants that fight represent the colonies that were unique, even though mtDNA haplotypes were identical. Thus, maternal haplotype cannot be the only criteria used to determine colony uniqueness or site fidelity. This research has also shown using mtDNA sequence that considerable distance is covered by alates. This likely accounts for the paucity of mtDNA haplotypes among colonies. Several site specific and unique colonies, some very close and others at opposite ends of the study area, had the same mtDNA haplotype, an unexpected result. Two mtDNA sequence markers, cytochrome oxidase I (COI) and cytochrome oxidase II (COI) have been collected from 20 individuals within 20 colonies. Agonism plus mtDNA sequence verification has been accomplished for three sites and SSRs have been determined for individuals in four colonies. Thus, enough preliminary data had been collected for an AFRI grant, Program Code - 91111. Questions addressed by the grant included is the genetic social structure of the black carpenter ant, Camponotus pennsylvanicus, ecology-dependent Will the higher temperatures predicted from climate change result in increased colony density and/or range expansion as predicted (Angilletta et al. 2007); and, will this expansion be the same across ecoregions PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: These data will provide the most complete picture to date of the sociogenetic structure of C. pennsylvanicus colonies. Improved understanding of colony spatial and temporal genetic structure and the ecological factors that affect them will provide predictive power in terms of spatial and temporal population expansion under climate change and should lead to the development of methods for predicting colony size and structure that are necessary for the improvements in management technologies in areas where carpenter ants must presently be managed There are several ways in which the knowledge of colony spatial organization and foraging range could help management efforts. First, if the efficacy of baits, or other methods, is influenced by the spatial structure of colonies, then it follows that the best management strategies can only be implemented if colony structure and inter-colony interactions are known. Some areas may favor small, localized colonies that can be effectively eliminated by baiting or other targeted treatments. In other habitats, larger, more spatially diffuse colonies may predominate, requiring a different approach. Second, the proposed research on the spatial organization of carpenter ant colonies using SSR data will serve as a model system for understanding the spatial structure and foraging ecology of other polydomous pest ants, including introduced invasive species such as the Argentine ant and the red imported fire ant. Finally, because C. pennsylvanicus is an important agricultural and landscape pest, and since it has been demonstrated that urban Formicidae are more thermally tolerant than rural Formicidae (Angilletta et al. 2007), this work will provide an opportunity to understand the similarities and differences in colony structure across a varied topology. The study has implications for the forestry and arboriculture industries and should result in improved management methods to protect nursery and urban shade trees during global climate change. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Few mtDNA haplotypes were found among colonies within the large study area. Thus, alates from a few colonies appear to dominate the sites. This finding further points to the fact that little is known about carpenter ant genetics or population genetic structure that would provide insights into carpenter ant population growth, and therefore, range expansion due to selection pressures such as climate change. There is considerable evidence that climate change will be a reality in the United States during the 21st century (IPCC.com). Also development, reproduction and expansion are strongly influenced by climate, particularly temperature. Thus, the genetic delineation of the social structure and gene flow of these ant colonies will aid in making predictions about black carpenter ant adaptive strategies based on genetic diversity (maternal and nuclear), population genetic structure, and the genetics behind agonistic displays. One of the objectives for the coming year, therefore,is to overlay the mtDNA data collected from each of the 20 colonies in this study with the nuclear SSR data being collected. Overall genetic diversity and female genetic contributions to each generation will provide insight into the method and speed of population expansion and control of such expansion.
Publications
- Jenkins, T. M., T. D. Eaton, D. Suiter. 2008. A longitudinal study of Camponotus pennsylvanicus (Hymenoptera: Formicidae) population structure: A preliminary report.2008. Proceedings of the 2008 National Conference on Urban Entomology, p.61.S.C.Jones(ed.)Tulsa, OK.
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