KIN-STRUCTURED COLONIZATION IN PHALACRUS-SUBSTRIATUS

The focus of this work is to examine the genetic structure of newly co lonized populations of the mycophagous beetle Phalacrus substriatus. T he newly colonized populations are characterized by small founding gro ups, often consisting only of females. Because an all-female colonizin g propagule can successfully found a new population, females must be m ated prior to dispersal. Furthermore, because of limited dispersal, fo unders come from only a limited set of populations, thereby increasing their probability of common origin (phi). The small founding groups, high probability of common origin and mating patterns of female beetle s generate a strong kin-structuring in P. substriatus as evidenced by the high average relatedness among first generation offspring (r = 0.1 90, weighted average over populations). The effective number of mating s per female (M-e) was estimated to be around 1.5. This yields an esti mate of the effective size of the newly colonized populations of 5.2. The probability of common origin was also high (0.80). The results are discussed in the light of how founding events may affect the structur ing of genetic variation within and between local populations.