TY - JOUR

T1 - Correlated evolution of male and female reproductive traits drive a cascading effect of reinforcement in Drosophila yakuba

AU - Comeault, Aaron A

AU - Venkat, Aarti

AU - Matute, Daniel R

PY - 2016/7/27

Y1 - 2016/7/27

N2 - Selection against maladaptive hybridization can drive the evolution of reproductive isolation in a process called reinforcement. While the importance of reinforcement in evolution has been historically debated, many examples now exist. Despite these examples, we typically lack a detailed understanding of the mechanisms limiting the spread of reinforced phenotypes throughout a species' range. Here we address this issue in the fruit fly Drosophila yakuba, a species that hybridizes with its sister species D. santomea and is undergoing reinforcement in a well-defined hybrid zone on the island of São Tomé. Within this region, female D. yakuba show increased postmating-prezygotic (gametic) isolation towards D. santomea when compared with females from allopatric populations. We use a combination of natural collections, fertility assays, and experimental evolution to understand why reinforced gametic isolation in D. yakuba is confined to this hybrid zone. We show that, among other traits, D. yakuba males from sympatric populations sire fewer progeny than allopatric males when mated to allopatric D. yakuba females. Our results provide a novel example of reinforcement acting on a postmating-prezygotic trait in males, resulting in a cascade of reproductive isolation among conspecific populations.

AB - Selection against maladaptive hybridization can drive the evolution of reproductive isolation in a process called reinforcement. While the importance of reinforcement in evolution has been historically debated, many examples now exist. Despite these examples, we typically lack a detailed understanding of the mechanisms limiting the spread of reinforced phenotypes throughout a species' range. Here we address this issue in the fruit fly Drosophila yakuba, a species that hybridizes with its sister species D. santomea and is undergoing reinforcement in a well-defined hybrid zone on the island of São Tomé. Within this region, female D. yakuba show increased postmating-prezygotic (gametic) isolation towards D. santomea when compared with females from allopatric populations. We use a combination of natural collections, fertility assays, and experimental evolution to understand why reinforced gametic isolation in D. yakuba is confined to this hybrid zone. We show that, among other traits, D. yakuba males from sympatric populations sire fewer progeny than allopatric males when mated to allopatric D. yakuba females. Our results provide a novel example of reinforcement acting on a postmating-prezygotic trait in males, resulting in a cascade of reproductive isolation among conspecific populations.

KW - Animals

KW - Drosophila/genetics

KW - Female

KW - Hybridization, Genetic

KW - Male

KW - Reproduction

KW - Reproductive Isolation

KW - Sexual Behavior, Animal

KW - Sympatry

U2 - 10.1098/rspb.2016.0730

DO - 10.1098/rspb.2016.0730

M3 - Article

C2 - 27440664

VL - 283

JO - Proceedings of the Royal Society B: Biological Sciences

JF - Proceedings of the Royal Society B: Biological Sciences

SN - 0962-8452

IS - 1835

ER -