Demographic behavior of social insect populations: the specific case of Formicidae

Monomorium pharaonis is one of the many invasive ant species which can be found associated with the endosymbiont bacteria of the genus Wolbachia. The association of M. pharaonis ants with Wolbachia is still being studied but is already known for giving the colony a reproductive advantage. The present work aimed to use biodemography analysis to check the effect of Wolbachia in the colonies of M. pharaonis ants, regarding its reproductive potential and rate of fertility (fertility pace). We took advantage of Birch (1948) methods to assess the effect of the bacteria in the whole colony, using data of the Dryad project. We evaluated the mean length of the generation, its capacity to multiply and the intrinsic rate of increase (r) and if the presence of the bacteria favors the longevity of the colony. The results obtained in the present work confirmed our initial hypothesis that the presence of the endosymbiont bacteria Wolbachia increased the reproductive rates of M. pharaonis colonies. We also found that the employment of interdisciplinary approaches highly contributes to obtaining more accurate and quantifiable results. The application of this methodological approach, highly contributed to obtain more accurate and directly driven results. For example, colonies infected with Wolbachia showed higher intrinsic growth rate (r) and thus enlightening with a new methodological approach results already presented in previous research. This "new" methodological approach revealed itself as a new tool extendible to other ants colonies or even other species. The use of statistical and biodemographic formulas and the adaptation of classical demography concepts for the study of the growth and reproduction of ant colonies revealed to be very useful.