Reproductive character displacement is not the only possible outcome of reinforcement (original) (raw)

The Genetics and Ecology of Reinforcement

Annals of the New York Academy of Sciences, 2009

Reinforcement, the evolution of prezygotic reproductive barriers by natural selection in response to maladaptive hybridization, is one of the most debated processes in speciation. Critics point to "fatal" conceptual flaws for sympatric evolution of prezygotic isolation, but recent theoretical and empirical work on genetics and ecology of reinforcement suggests that such criticisms can be overcome. New studies provide evidence for reinforcement in frogs, fish, insects, birds, and plants. While such evidence lays to rest the argument over reinforcement's existence, our understanding remains incomplete. We lack data on (1) the genetic basis of female preferences and the links between genetics of pre-and postzygotic isolation, (2) the ecological basis of reproductive isolation, (3) connections between prezygotic isolation between species and within-species sexual selection (potentially leading to a "cascade" of effects on reproductive isolation), (4) the role of habitat versus mate preference in reinforcement, and (5) additional detailed comparative studies. Here, we review data on these issues and highlight why they are important for understanding speciation.

Reinforcement: the Road Not Taken

Trends in Ecology & Evolution, 2002

Reinforcement, a process whereby natural selection strengthens prezygotic isolation between sympatric taxa, has gained increasing attention from evolutionary biologists over the past decade. This resurgence of interest is remarkable given that, in the 1980s, most evolutionary biologists considered reinforcement to be, at best, a process that rarely occurred in nature. Although studies of reinforcement are now an important component of speciation research, we still lack a clear understanding of when reinforcement should occur. Theoretical models have suggested that genetic architecture, population structure and the type of selection influence the action of reinforcement. Still to be considered are the consequences of variation in mating system and patterns of sperm or pollen utilization on the likelihood of reinforcement. We argue that traveling down The Road Not Taken (apologies to Frost), that is, taking into consideration mating system and patterns of gamete utilization, leads to novel and more precise predictions of the circumstances under which reinforcement should occur.

Reinforcement

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The Effects of Gene Flow on Reinforcement

Evolution, 1997

We explore the possibility that differences in the pattern of gene flow between populations may affect the evolution of reinforcement by comparing pairs of populations undergoing one-way migration versus symmetric migration. The case of symmetric migration is modeled by a two-island model, where the two populations exchange equal proportions of migrants each generation. One-way migration is modeled by a continent-island model, where migration is in one direction from a large continental population with a fixed genotype to an island population whose genotype frequencies can vary. Hybrid inviability is assumed to be caused by epistatic interactions between background loci. We examine the spread of an introduced preference allele for a previously unpreferred male trait that characterizes one of the populations. Computer simulations indicate that with a weak introduced preference, reinforcement is possible under a wide range of parameter values in a symmetric migration model but cannot occur in a one-way migration model. Reinforcement with one-way migration can occur only with a very strong introduced preference and very strong selection against hybrids. Our results suggest that the speciation of a peripheral isolate, which undergoes essentially one-way migration, may be difficult to complete if secondary contact occurs before reproductive isolation is fully developed.

Plasticity in reproductive behaviours as a response to ecological changes

2018

Title: Plasticity in reproductive behaviours as a response to ecological changes Miguel A. Gómez-Llano The thesis presented here utilizes a variety of methods and study systems to address how ecological promote plasticity in reproductive behaviours. We study mate choice, copulation and parental care as the different reproductive behaviours, as they can be envisioned as representatives of different stages of the reproductive cycle and can be subject to different selection pressures. With the use of computer simulations we study the conditions of sex ratio and cost of courting under which a learned mate preference in males or in both sexes can evolve. We found that for males, maternal imprinting is the most advantageous imprinting strategy, but when both sexes imprint, paternal imprinting in both sexes is the most advantageous strategy. We show that environmental change can lead to the evolution of sexual imprinting by both sexes. A study using mesocosm and mating trial experiments, m...