Evidence for ecology's role in speciation

Abstract

A principal challenge in testing the role of natural selection in speciation is to connect the build-up of reproductive isolation between populations to divergence of ecologically important traits. Demonstrations of 'parallel speciation', or assortative mating by selective environment, link ecology and isolation, but the phenotypic traits mediating isolation have not been confirmed. Here we show that the parallel build-up of mating incompatibilities between stickleback populations can be largely accounted for by assortative mating based on one trait, body size, which evolves predictably according to environment. In addition to documenting the influence of body size on reproductive isolation for stickleback populations spread across the Northern Hemisphere, we have confirmed its importance through a new experimental manipulation. Together, these results suggest that speciation may arise largely as a by-product of ecological differences and divergent selection on a small number of phenotypic traits.

Costly plastic morphological responses to predator specific odour cues in three-spined sticklebacks (Gasterosteus aculeatus)

“…Predominantly heritable specialisation by adaptive divergence would in contrast lead to alternatively specialised populations in which individuals mate assortatively (Dieckmann et al 2004;Gavrilets 2004). In fact, adaptive divergence driven by ecological selection pressure is well documented in various classic examples of lake-dwelling sticklebacks (Schluter 2000;Bolnick and Lau 2008), as well as in migrating-resident stickleback pairs (McKinnon et al 2004), and in different resident lake or riverine populations (Reusch et al 2001;Hendry et al 2009 for a review).…”

Genetic diversity, population structure, and traditional culture of Camellia reticulata

“…Nei's genetic distances between populations (Nei, 1978) (also generated with POPGEN32) were used to construct unweighted pair group method arithmetic average (UPGMA) dendrograms in NTSYSpc 2.11 after running 100 replicates (McKinnon, Mori, Blackman, & Lior, 2004). Genetic diversity ( H ) was calculated at two levels: the average diversity within populations ( H pop ) and the total diversity ( H t ).…”

Physiological and genetic basis for variation in migratory behavior in the three-spined stickleback, Gasterosteus aculeatus

“…First, the G. aculeatus species complex includes both anadromous and freshwaterresident forms of G. aculeatus (Bell and Foster 1994;McKinnon and Rundle 2002). The ancestral forms of G. aculeatus are considered anadromous, whereas freshwater-resident forms have evolved independently from the anadromous forms in multiple lineages (Haglund et al 1992;Orti et al 1994;McPhail 1999, 2000;McKinnon et al 2004;Colosimo et al 2005). The anadromous forms of G. aculeatus usually migrate to freshwater or estuaries in spring (Table 1), while juveniles migrate to the sea in fall (Table 2), although there are substantial variation in the timing of migration (Tables 1, 2).…”

“…2b). Although the extent of gene flow between anadromous and resident forms varies according to the geography of the location, anadromous and resident forms are often reproductively isolated and genetically differentiated because of multiple isolating barriers, including ecogeographical isolation (Hagen 1967), temporal isolation (Hagen 1967), sexual isolation (Hay and McPhail 1975;McKinnon et al 2004), and postzygotic isolation against hybrids (Jones et al 2006(Jones et al , 2008.…”