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Full-Text Articles in Life Sciences
Sexual Selection, Speciation And Constraints On Geographical Range Overlap In Birds, Christopher Cooney, Joseph A. Tobias, Jason T. Weir, Carlos A. Botero, Nathalie Seddon
Sexual Selection, Speciation And Constraints On Geographical Range Overlap In Birds, Christopher Cooney, Joseph A. Tobias, Jason T. Weir, Carlos A. Botero, Nathalie Seddon
Biology Faculty Publications & Presentations
The role of sexual selection as a driver of speciation remains unresolved, not least because we lack a clear empirical understanding of its influence on different phases of the speciation process. Here, using data from 1306 recent avian speciation events, we show that plumage dichromatism (a proxy for sexual selection) does not predict diversification rates, but instead explains the rate at which young lineages achieve geographical range overlap. Importantly, this effect is only significant when range overlap is narrow (< 20%). These findings are consistent with a ‘differential fusion’ model wherein sexual selection reduces rates of fusion among lineages undergoing secondary contact, facilitating parapatry or limited co-existence, whereas more extensive sympatry is contingent on additional factors such as ecological differentiation. Our results provide a more mechanistic explanation for why sexual selection appears to drive early stages of speciation while playing a seemingly limited role in determining broad-scale patterns of diversification.
Social Amoebae Mating Types Do Not Invest Unequally In Sexual Offspring, T E. Douglas, David C. Queller, Joan E. Strassmann
Social Amoebae Mating Types Do Not Invest Unequally In Sexual Offspring, T E. Douglas, David C. Queller, Joan E. Strassmann
Biology Faculty Publications & Presentations
Unequal investment by different sexes in their progeny is common and includes differential investment in the zygote and differential care of the young. The social amoeba Dictyostelium discoideum has a sexual stage in which isogamous cells of any two of the three mating types fuse to form a zygote which then attracts hundreds of other cells to the macrocyst. The latter cells are cannibalized and so make no genetic contribution to reproduction. Previous literature suggests that this sacrifice may be induced in cells of one mating type by cells of another, resulting in a higher than expected production of macrocysts …