Facultative polyandry, polygyny and worker reproduction in Lasius fuliginosus
Tobias van Elst, Tobias van Elst , Jürgen Gadau
Institute for Evolution and Biodiversity, University of Münster, 48149 Münster, Germany; Institute for Evolution and Biodiversity, University of Münster, 48149 Münster, Germany ; Institute for Evolution and Biodiversity, University of Münster, 48149 Münster, Germany
Ant societies exhibit striking diversity in their social systems, including variation in the number of queens and mating partners. Knowledge on the number of breeders in a colony is crucial for a better understanding of the evolution of social insect life history traits such as reproductive skew or worker reproduction. Little is known about the breeding system of the formicine ant Lasius fuliginosus even though it is widely distributed in the Palearctic and able to compete ecologically with dominant genera like Formica. Moreover, L. fuliginosus has a particularly interesting life history in that it is a temporary social parasite of several Lasius species that are temporary social parasites themselves. To further our understanding, we studied the number of (reproductive) queens and mating partners of L. fuliginosus colonies in a population in Münster, Germany. We genotyped workers for each of 33 colonies and males for thirteen of these colonies for four polymorphic microsatellite markers. Our results show that 29 of 33 colonies were monogynous and monandrous and two colonies were monogynous but polyandrous. Workers of the remaining two colonies were derived from multiple queens, possibly due to adoption of unrelated queens after the original queen’s death. Furthermore, genotyping of male offspring provided evidence for worker reproduction in three colonies, potentially also in response to queen orphanage. To our knowledge, this is the first study to provide molecular insights into the breeding system of L. fuliginosus which appears to be characterized by facultative polyandry and polygyny. In addition, L. fuliginosus now presents the second species in the genus Lasius for which worker reproduction has been documented.