Populationsbiologie zweier gefährdeter sozialparasitischer Ameisenarten
Final Report Abstract
The ant genus Myrmoxenus comprises about a dozen currently recognized species of slave-making ants, degenerate slave-makers, and workerless Inquilines, which all are listed as threatened by IUCN. Aim of our project was to determine the genetic population and colony structure of two species, the Central European slave-maker M. ravouxi and the degenerate slave-maker M. kraussei from Northern Italy. From the relatively high genetic diversity we conclude that populations are larger than previously thought, but the high FST- and D-values indicate that even neighboring populations (< 3km) are isolated from one another. This reflects a limited dispersal capability of the parasite and might explain why host populations in restored grassland patches are not readily colonized. Though locally relatively abundant, Myrmoxenus therefore appears to be vulnerable because they cannot easily evade habitat destruction by settling in adjacent areas. Specific conservation measures for Myrmoxenus should therefore concentrate on the maintenance of large and old host populations rather than the renaturalization of agricultural land. A phylogeny of the genus based on mtDNA sequences shows that the worker caste has been lost convergently at least twice and that a number of taxa are not clearly distinct. This might indicate incomplete lineage sorting in a rapidly diverging clade or, more likely, the synonymy of several of the described taxa.
