AbstrAct.-Working in the Galápagos Islands and surrounding areas, we examined the relationship between population structure, a precursor to allopatric speciation, in species of reef fishes that exhibit different life history traits and three types of distributions in a nested setting: endemic (restricted to the Galápagos Islands), insular (Galápagos and neighboring islands), and Panamic (tropical eastern Pacific). We used a combination of population structure and coalescent approaches to assess the degree of genetic population structure in the three groups of fish species. In addition, we evaluated the level of inter-island genetic diversity in endemic species to determine if Galápagos fishes, like their terrestrial counterparts, could be used as a system to study allopatric speciation in the sea. We found that in general, there was no correlation between distribution ranges, life history traits, and population structure, except for Dialommus fuscus Gilbert, 1891, a Galápagos endemic that lives in the uppermost intertidal area, and as predicted, shows very strong population structure. We found the highest number of statistically significant population pairwise F st comparisons in endemic species. In addition, three out of four endemic species showed significant population pairwise F st [D. fuscus, Lepidonectes corallicola (Kendall and radcliffe, 1912), and Lythrypnus gilbert (Heller and snodgrass, 1903)]. These results suggest that endemic Galápagos Islands reef fishes may be a promising group of species to study phylogeographic patterns of speciation. "The (Galápagos) archipelago does not appear to offer a good laboratory for researching the impact of isolation, because the barren islands do not harbor many isolated fish pools. "David starr Jordan (in a letter to robert Evans snodgrass, 1898)

According to Bateman's principle, female fecundity is limited relative to males, setting the expectation that males should be promiscuous, while females should be choosy and select fewer mates. However, several surfperches (Embiotocidae) exhibit multiple paternity within broods indicating that females mate with multiple males throughout the mating season. Previous studies found no correlation between mating success and reproductive success (i.e., a Bateman gradient). However, by including samples from a broader range of reproductive size classes, we found evidence of a Bateman gradient in two surfperch species from distinct embiotocid clades. Using microsatellite analyses, we found that 100% of the spotfin surfperch families sampled exhibit multiple paternity (Hyperprosopon anale, the basal taxon from the only clade that has not previously been investigated) indicating that this tactic is a shared reproductive strategy among surfperches. Further, we detected evidence for a Bateman gradient in H. anale; however, this result was not significant after correction for biases. Similarly, we found evidence for multiple paternity in 83% of the shiner surfperch families (Cymatogaster aggregata) sampled. When we combine these data with a previous study on the same species, representing a larger range of reproductive size classes and associated brood sizes, we detect a Bateman gradient in shiner surfperch for the first time that remains significant after several conservative tests for bias correction. These results indicate that sexual selection is likely complex in this system, with the potential for conflicting optima between sexes, and imply a positive shift in fertility (i.e., increasing number) and reproductive tactic with respect to the mating system and number of sires throughout the reproductive life history of females. We argue that the complex reproductive natural history of surfperches is characterized by several traits that may be associated with cryptic female choice, including protracted oogenesis, uterine sac complexity, and sperm storage.

Molecular technology can identify species noninvasively from faeces found in the field. We describe a fast and reliable genetic method that differentiates faeces of five potentially sympatric North American canids without using multiple primer sets or restriction enzyme digestion. Our primer set amplifies a short fragment (237-288 bp) of the mitochondrial d-loop that is a different length in each species: kit fox (Vulpes macrotis), red fox (Vulpes vulpes), gray fox (Urocyon cinereoargenteus), coyote (Canis latrans), and dog (Canis familiaris). We extensively tested our technique using published and novel d-loop sequences and then applied it to two large faecal data sets collected in California and Virginia. It provides an efficient tool for noninvasively distinguishing sympatric canids in diverse regions of North America.

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