Kin-structured colonization in Phalacrus substriatus

Abstract

The focus of this work is to examine the genetic structure of newlycolonized populations of the mycophagous beetle Phalacrus substriatus.The newly colonized populations are characterized by small foundinggroups, often consisting only of females. Because an all-female colonizingpropagule can successfully found a new population, females must bemated prior to dispersal. Furthermore, because of limited dispersal,founders come from only a limited set of populations, thereby increasingtheir probability of common origin (phi). The small founding groups,high probability of common origin and mating patterns of female beetlesgenerate a strong kin-structuring in P. substriatus as evidencedby the high average relatedness among first generation offspring(r = 0.190, weighted average over populations). The effective numberof matings per female (M-e) was estimated to be around 1.5. Thisyields an estimate of the effective size of the newly colonized populationsof 5.2. The probability of common origin was also high (0.80). Theresults are discussed in the light of how founding events may affectthe structuring of genetic variation within and between local populations.