Evolution and consequences of polygyny in leptothoracine ants
Sammanfattning: In this thesis the evolution and consequences of multiple queen societies (polygyny) in leptothoracine ants are discussed. The majority of the studies have been conducted on the boreal species Leptothorax acervorum, but polygynous behaviour is also discussed in a broader sense concerning ant species in general. In L. acervorum the intra-colony relatedness is high. Relatedness in monogynous colonies is higher than in polygynous, and the relatedness between colony mates decreases with increasing number of queens present in the nest. The number of queens contributing offspring is lower than the actual number of functional queens present in the nest. L. acervorum is considered to be a secondary polygynous species where young queens are adopted back to the natal colony after their mating flight, and new colonies are established by means of budding or colony fission. Aggregations of maternally related colonies occur, supporting the idea of budding. Furthermore, unrelated queens are found in some colonies, indicating that adoption occurs. The L.acervorum queen is only twice the size of the worker, and the number of queens in polygynous colonies decreases during early summer. Polygyny and queen morphology in relation to colony founding strategies in ants are discussed. Sex allocation in L. acervorum is influenced by colony size, production, and queen number. The sex ratio is negatively correlated with colony size and productivity, and positively correlated with the number of queens in the colony. DNA sequence data indicates that leptothoracine ants can be divided into two lineages, the Myrafant and the Leptothorax s. str. groups. Social parasitism has originated independently in the two groups, twice in the former and possibly two or three times in the latter group. True inquilinism only occurs in the Leptothorax group which is characterised by free living species with polygynous behaviour, whereas dulosis and pseudoinquilinism occur in both groups. This suggests that polygyny is a prerequisite for inquilinism, while other parasitic behaviours most likely have originated in monogynous species.
Denna avhandling är EVENTUELLT nedladdningsbar som PDF. Kolla denna länk för att se om den går att ladda ner.