Department of Entomology
I am interested in evolutionary biology, particularly the patterns and processes that give rise to the diversity of life and the evolution of social and cooperative behaviors in insects. Because I am currently mainly focused on the study of fire ants and thief ants (genus Solenopsis), these traits include worker size polymorphism, queen number, social parasitism, and invasiveness; each of these traits vary widely among closely related species in this genus, rendering comparative phylogenetic approaches ideal for the study of their evolution.
Sociogenomics and the Genetic Regulation of Social Behavior
I have studied the molecular evolution and regulation of queen number in the Red Imported Fire Ant, Solenopsis invicta, as well as other fire ants using behavioral and genetic approaches. In particular, we have focused on allelic variation in the nuclear protein-coding gene, General protein-9 (Gp-9), because worker allele frequencies predict a colony’s social organization (and Gp-9 genotype). Currently, collaborators and I are conducting a large population genomic study of the socially polymorphic fire ants within a phylogenetic framework in order to understand the molecular evolution and genomic architecture of the region surrounding Gp-9. This region is of interest, because it has been hypothesized to be a rare example of a “green beard” gene region that also acts as a selfish genetic element, attracting other selfish genetic elements (i.e., transposable elements) and leading to a general degradation of the region in a manner similar to the evolution of a sex chromosome.
- Gotzek D., M. Strand, K. Ross, L. Keller, and M. Beck (in prep.) Patterns of expression and protein abundance of Gp-9, a candidate gene implicated in regulation of fire ant social behavior.
- Gotzek D., H. et al. (2011) Odorant binding proteins of the Red Imported Fire Ant, Solenopsis invicta (Hymenoptera: Formicidae): An example of the problems facing the analysis of widely divergent proteins. PLoS One 6:e16289.
- Wurm Y., et al. (2011) The genome of the fire ant Solenopsis invicta. PNAS 108:5679–5684.
- Gotzek D., K.G. Ross (2009) Current status of a model system: The gene Gp-9 and its association with social organization in fire ants. PLoS One 4:e7713.
- Gotzek D., K.G. Ross (2008) Experimental conversion of colony social organization in fire ants (Solenopsis invicta): Worker genotype manipulation in absence of queen effects. J Insect Behav 21:337-350.
- Gotzek D., D.D. Shoemaker, K.G. Ross (2007) Molecular variation at a candidate gene implicated in the regulation of fire ant social behavior. PLoS One 2:e1088.
- Gotzek D., K.G. Ross (2007) Genetic regulation of colony social organization in fire ants: an integrative overview. Quart Rev Biol 82:201-226.
- Costa J.T., D.A. Gotzek, D.H. Janzen (2003) Late-instar shift in foraging strategy and trail pheromone use by caterpillars of the Neotropical moth Arsenura armida (Cramer) (Lepidoptera: Saturniidae: Arsenurinae). J Lep Soc 57:220-229.
Phylogenomics and Genome Evolution
Elucidating the relationships among taxa is central to understanding much in evolutionary biology and I have extensively utilized phylogenies in my research. Currently I am using multi-locus and phylogenomic approaches to estimate species trees across several systematic levels in ants (e.g., Pheidole obscurithorax, genus Solenopsis, Neartic Nylanderia, Ant AToL). I complement my phylogenetic research with coalescent-based population genomic analyses to better understand inter- and intraspecific evolutionary processes. Where possible, I like to include other types of data, such as morphology, ecological niche modeling, or biochemical characters, for an integrative and multi-disciplinary approach. These large scale and in-depth evolutionary genetic projects will provide the systematic and taxonomic framework for future comparative studies on fire ants and other taxa.
- Brady, S.G. et al. (in prep) The phylogeny of Nearctic Nylanderia and implications for the evolution of social parasitism.
- Gotzek D. et al. (in prep) Species tree of fire ants: alternate methods to calibrating nodes.
- Gotzek D., J. Clarke, D. Shoemaker (2010) Mitochondrial genome evolution in fire ants (Hymenoptera: Formicidae). BMC Evol Biol 10:300.
- Ross K.G., et al. (2010) Species delimitation: A case study in a problematic ant taxon. Syst Biol 59:162-184.
- Kadereit G., et al. (2004) Origin and age of Australian Chenopodiacaea. Org Div Evol 5:59-80.
Through my work with fire ants, I have also become interested in the evolution and determinants of invasiveness, because two of the globally most damaging invasive insects are fire ants (
- Gotzek D., et al. (in prep.) Global Invasion History of the Tropical Fire Ant, Solenopsis geminata.
- Gotzek D., D.D. Shoemaker, and N.B. Barr. (in review) An allele-specific PCR assay to indentify native from invasive fire ants in North America. Submitted to J. Econ Entomol.
- Gotzek D., S.G. Brady, R.J. Kallal, J.S. LaPolla. (2012) The importance of using multiple approaches for identifying emerging invasive species: the case of the Rasberry Crazy Ant in the United States. PLoS One 7:e54314
As part of my increasing taxonomic focus, I have become increasingly interested in the study of biodiversity. I regard DNA barcoding as useful tool for a rapid, heuristic approach in large, high-throughput studies of diversity, especially in taxonomically difficult groups, such as ants.
I am currently barcoding ant collections from Cambodia with the Consortium for the Barcode of Life at the Smithsonian Institution and will continue to add to this collection since Cambodia has one of the most understudied ant faunas in the world. This work will also have conservation implications, since ants, as key ecosystem engineers, are useful biomonitors. Since Cambodia currently has one of the highest rates of habitat destruction in Southeast Asia, there is a particular relevance to this work and I am keen to pursue similar projects. To this end, collaborators and I recently received a three-year grant to study the biodiversity of Cambodian leaf- and treehoppers (Membracoidea) and we are currently seeking to expand this through a multi-institution collaborative grant to survey the insect fauna of Indochina (Myanmar, Thailand, Cambodia, Laos, Vietnam, and peninsular Malaysia) within a comparative biogeographic framework.