Genetic status and timing of a weevil introduction to Santa Cruz Island, Galápagos

Successful invasive species can overcome or circumvent the potential genetic loss caused by an introduction bottleneck through a rapid population expansion and admixture from multiple introductions. We explore the genetic makeup and the timing of a species introduction to Santa Cruz Island in the Galápagos archipelago. We investigate the presence of processes that can maintain genetic diversity in populations of the broad-nosed weevil Galapaganus howdenae howdenae. Analyses of combined genotypes for 8 microsatellite loci showed evidence of past population size reductions through moment and likelihood-based estimators. No evidence of admixture through multiple introductions was found, but substantial current population sizes (N0 298, 95% HPD 50-2300), genetic diversity comparable to long-established endemics (Mean number of alleles=3.875) and lack of genetic structure across the introduced range (ΦST = 0.01359) could suggest that foundations are in place for populations to rapidly recove...