Abstract ID: 3.12839 | Accepted as Poster | Poster | TBA | TBA

The vast majority of individuals in an ant colony are sterile females, that is, workers. Normally, exclusively queens and males are the fertile individuals. After mating, queens can lay eggs, from which female individuals (diploids) and/or males (haploids) will hatch. Nevertheless, under specific ecological circumstances, workers can lay eggs, from which haploid males or diploid females, that is, cloned workers, can originate by asexual reproduction. Lasius fuliginosus is a well-studied ant species because of its peculiar ecology that occurs up to the timber line and plays an important role in mountain ecosystems. This fungus breeding ant is famous for building its paper-nests using shredded wood, honey dew, and the hyphae of symbiotic fungi. The breeding system is peculiar (queens must penetrate the nests of other Lasius species to reproduce), and many details still await discovery. The aim of this study was to investigate within-nest relatedness between individuals in several L. fuliginosus as a basis to evaluate the occurrence of asexual reproduction. We sampled 744 individuals from 62 different nests in five populations in Austria and Germany along elevational transects and used 12 nuclear microsatellite loci for evaluating genetic diversity. We estimated the linkage disequilibrium, deviations from Hardy-Weinberg equilibrium, heterozygosity, allele frequency, allelic richness, probability of identity, and genetic relatedness inside each nest. We found clones originating from asexual reproduction in nearly half of the L. fuliginosus nests analyzed. This now opens up questions about proximate causations, such as if clonal individuals are produced by workers and / or queens. The latter would mean that sexual and asexual reproduction by the same individual coexists. Our findings also open up questions about ultimate causations, such as the dependence of asexuality in this ant on environmental conditions. In more detail, as environmental conditions become more extreme at higher altitudes, ant populations may benefit from increasing colony size through asexual reproduction, while avoiding the risks associated with sexual reproduction. The presence of asexual reproduction in L. fuliginosus provides new insights into the reproductive mode and social structure of ants generally as it does into mountain ecosystems.