|Allozyme characterization of Hogna species (Araneae, Lycosidae) of the Galápagos Archipelago|Baert, L.; Hendrickx, F.; Maelfait, J.-P. (2008). Allozyme characterization of Hogna species (Araneae, Lycosidae) of the Galápagos Archipelago. J. arachnol. 36(2): 411-417. dx.doi.org/10.1636/CA07-091.1
In: The journal of arachnology. American Arachnological Society: Lubbock, Tex.. ISSN 0161-8202, more
Wolf spiders, speciation, island biogeography, ecological speciation
The colonization of species on remote islands may result in phenotypic diversification and ultimately speciation. On the Galápagos Archipelago, seven very closely related morpho-species of the wolf spiders genus Hogna are distinguishable based on small somatic and genital differences. Based on habitat preference, these species can broadly be categorized into (i) three ‘‘high elevation species’’ occurring on the volcanic highlands, (ii) three ‘‘coastal dry’’ species occurring in dune habitats along the coast, and (iii) one generalist species which is chiefly found in wet coastal habitats such as salt marshes but also in wet habitats at higher altitudes. To determine the degree of reproductive isolation among these morpho-species, we investigated gene flow among populations and species based on nine allozyme loci. Genetic analysis by means of genetic distance estimates and cluster agglomerative analyses confirmed the status of the defined morpho-species. Allele frequencies were highly similar among populations within a species but differed profoundly among species. Genetic differentiation within the generalist species was generally very low. There were no constant differences between high elevation and coastal populations for this species. Neutral genetic divergence between species appeared to correspond more to geographic distribution rather than to a clear separation of the two different ecological groups within an island. This suggests that a parallel parapatric divergence between high elevation and coastal dry species may have taken place on the oldest islands of San Cristobal and Santa Cruz.