Data from: Multifaceted, cross-generational costs of hybridization in sibling Drosophila species

Maladaptive hybridization, as determined by the pattern and intensity of selection against hybrid individuals, is an important factor contributing to the evolution of prezygotic reproductive isolation. To identify the consequences of hybridization between Drosophila pseudoobscura and D. persimilis, we estimated multiple fitness components for F1 hybrids and backcross progeny and used these to compare the relative fitness of parental species and their hybrids across two generations. We document many sources of intrinsic (developmental) and extrinsic (ecological) selection that dramatically increase the fitness costs of hybridization beyond the well-documented F1 male sterility in this model system. Our results indicate that the cost of hybridization accrues over multiple generations and reinforcement in this system is driven by selection against hybridization above and beyond the cost of hybrid male sterility; we estimate a fitness loss of >95% relative to the parental species across two generations of hybridization. Our findings demonstrate the importance of estimating hybridization costs using multiple fitness measures from multiple generations in an ecologically relevant context; so doing can reveal intense postzygotic selection against hybridization and thus, an enhanced role for reinforcement in the evolution of populations and diversification of species

Multifaceted, Cross-Generational Costs of Hybridization in Sibling <i>Drosophila</i> species

<div><p>Maladaptive hybridization, as determined by the pattern and intensity of selection against hybrid individuals, is an important factor contributing to the evolution of prezygotic reproductive isolation. To identify the consequences of hybridization between <i>Drosophila pseudoobscura</i> and <i>D. persimilis</i>, we estimated multiple fitness components for F1 hybrids and backcross progeny and used these to compare the relative fitness of parental species and their hybrids across two generations. We document many sources of intrinsic (developmental) and extrinsic (ecological) selection that dramatically increase the fitness costs of hybridization beyond the well-documented F1 male sterility in this model system. Our results indicate that the cost of hybridization accrues over multiple generations and reinforcement in this system is driven by selection against hybridization above and beyond the cost of hybrid male sterility; we estimate a fitness loss of >95% relative to the parental species across two generations of hybridization. Our findings demonstrate the importance of estimating hybridization costs using multiple fitness measures from multiple generations in an ecologically relevant context; so doing can reveal intense postzygotic selection against hybridization and thus, an enhanced role for reinforcement in the evolution of populations and diversification of species.</p> </div

Data from: Multifaceted, cross-generational costs of hybridization in sibling Drosophila species

Includes all data on flies reared in the laboratory as part of the experiments described in the paper. Read Me file describes each worksheet of the data file

Frequency of developmental abnormalities by offspring class.

<p>Abnormal abdominal tergites (black) and reduced testes size (gray) are shown as a function of their frequency in Assay 4 (+/- 1 SE). Inset shows examples of wildtype (WT) and abnormal tergite expression (BC). Scale bar 1mm. </p

Lifecycle of <i>Drosophila</i>.

<p>Fitness of F1 hybrid and backcross progeny relative to the parental species was assessed for several traits throughout the lifecycle of the fly. Traits for which a significant fitness effect was seen are shown in italics.</p

Upwind flight performance.

<p>Parental species (PS; <i>Drosophila pseudoobscura</i> and <i>D. persimilis</i>), F1 hybrid (F1), and backcross (BC) male (above) and female flies (below). Line shows the proportion of individuals that were able to fly into an increasing headwind. </p