Comparison of population structuring in sympatric octopus species with and without a pelagic larval stage

An understanding of the influence of life history on dispersal capability is central to a range of disciplines within ecology and evolution. While studies have investigated this question by contrasting spatial population structuring in taxa that differ in life history, in the vast majority such comparisons differ in space and time, and therefore environmental factors may have contributed. Here, population structure of a holobenthic (i.e. direct developing) octopus, Octopus pallidus, was investigated genetically. This was compared to existing genetic data for a co-occurring merobenthic (i.e. planktonic larvae) species, Macroctopus maorum. Greater spatial genetic structuring was evident in O. pallidus than M. maorum. Patterns were consistent with isolation by distance in O. pallidus, but appeared related to oceanographic circulation systems in M. maorum, suggesting distance-dependent adult dispersal and current-mediated larval dispersal, respectively. Genetic population structuring in O. pallidus also largely corroborated inferences based on stylet microchemistry, indicating the utility of these environmental signatures. This study enables stronger predictions to be made regarding the dispersal capabilities and spatial population structuring of other cephalopods based on life history.