For my Master’s thesis, I researched two closely related species of ants from the genus Lasius at the University of Munich in Germany. Until recently, the two species were thought to be a single species that was very polymorphic, but were split apart from each other in the 1990’s by a taxonomist. The two species were Lasius platythorax and Lasius niger. Preliminary observations indicated that both species occur in the same habitats, which prompted the question about how they can coexist with one another. The goal of my project was to evaluate the degree of their ecological, chemical, and genetic differentiation. In pursuit of those goals, I took several ecological observations, including laying out a systematic baiting experiment with tuna and honey baits. In addition, I collected individuals from both platythorax and niger nests and analyzed their cuticular hydrocarbons using GC-MS. Finally, I also employed microsatellites to evaluate genetic structure in both populations. I found that species were significantly different from one another along each axis, which may be how they are able to coexist in the same habitat.