Data from: Asymmetrical sexual isolation but no postmating isolation between the closely related species Drosophila suboccidentalis and Drosophila occidentalis

Background: During the speciation process several types of isolating barriers can arise that limit gene flow between diverging populations. Studying recently isolated species can inform our understanding of how and when these barriers arise, and which barriers may be most important to limiting gene flow. Here we focus on Drosophila suboccidentalis and D. occidentalis, which are closely related mushroom-feeding species that inhabit western North America and are not known to overlap in geographic range. We investigate patterns of reproductive isolation between these species, including premating, postmating prezygotic, and postzygotic barriers to gene flow. Results: Using flies that originate from a single population of each species, we find that the strength of premating sexual isolation between these species is asymmetric: while D. occidentalis females mate with D. suboccidentalis males at a reduced but moderate rate, D. suboccidentalis females discriminate strongly against mating with D. occidentalis males. Female hybrids will mate at high rates with males of either species, indicating that this discrimination has a recessive genetic basis. Hybrid males are accepted by females of both species. We do not find evidence for postmating prezygotic or postzygotic isolating barriers, as females use the sperm of heterospecific males and both male and female hybrids are fully fertile. Conclusions: Premating isolation is substantial but incomplete, and appears to be the primary form of reproductive isolation between these species. If these species do hybridize, the lack of postzygotic barriers may allow for gene flow between them. Given that these species are recently diverged and are not known to be sympatric, the level of premating isolation is relatively strong given the lack of intrinsic postzygotic isolation. Further work is necessary to characterize the geographic and genetic variation in reproductive isolating barriers, as well as to determine the factors that drive reproductive isolation and the consequences that isolating barriers as well as geographic isolation have had on patterns of gene flow between these species.Pure Species Mating RatesThis file contains data from the paper entitled "Asymmetrical sexual isolation but no postmating isolation between the closely related species Drosophila suboccidentalis and Drosophila occidentalis". This specific file contains data detailing pure species mating rates (Figure 1 from the paper). Each row represents a single pair of flies that were involved in a no-choice mate trial. A "1" in the "Mated(1=Yes)" column represents a pair of flies that successfully copulated within the allotted time frame. A "0" in this column indicated that the pair failed to copulate. The "Female_Species" column indicates the species of female in each pairing. The "Male_Species" column indicates the species of male in each pairing. "Suboccidentalis" refers to a pure Drosophila suboccidentalis individual. "Occidentalis" refers to a pure Drosophila occidentalis individual.Pure and Hybrid Female's Egg CountsThis file contains data from the paper entitled "Asymmetrical sexual isolation but no postmating isolation between the closely related species Drosophila suboccidentalis and Drosophila occidentalis". This specific file contains data detailing pure species female and hybrid individual female egg production (Figure 3 from the paper). Each row represents a single pair of flies. These flies were mated and the number of eggs produced by each female was tallied in the column titled "Egg_Count". The "Female_Type" column indicates whether the female fly in each pairing was a pure species individual or a hybrid individual. The "Male_Type" column indicates whether the male fly in each pairing was a pure species individual or a hybrid individual. "Suboccidentalis" refers to a pure species Drosophila suboccidentalis individual. "Occidentalis" refers to a pure species Drosophila occidentalis individual. "F1(OxS)" refers to a hybrid individual generated by crossing a Drosophila occidentalis female to a Drosophila suboccidentalis male. "F1(SxO)" refers to a hybrid individual generated by crossing a Drosophila suboccidentalis female to a Drosophila occidentalis male.Pure Species Offspring CountThis file contains data from the paper entitled "Asymmetrical sexual isolation but no postmating isolation between the closely related species Drosophila suboccidentalis and Drosophila occidentalis". This specific file contains data detailing pure species female and hybrid individual female progeny production (Figure 4 from the paper). Each row represents a single pair of flies. These flies were mated and the number resulting adult offspring produced was tallied in the column titled "Progeny_Count". The "Female_Species" column indicates the species of female in each pairing. The "Male_Species" column indicates the species of male in each pairing. "Suboccidentalis" refers to a pure species Drosophila suboccidentalis individual. "Occidentalis" refers to a pure species Drosophila occidentalis individual.Pure Species and Hybrid Male FertilityThis file contains data from the paper entitled "Asymmetrical sexual isolation but no postmating isolation between the closely related species Drosophila suboccidentalis and Drosophila occidentalis". This specific file contains data detailing pure species and hybrid individual female egg production (Figure 5 from the paper). Each row represents a set containing a single male fly and three female flies. These flies were mated and the number of progeny produced was tallied in the column titled "Progeny_Count". The "Female_Type" column indicates whether the female flies in each set was a pure species individual or a hybrid individual. The "Male_Type" column indicates whether the male fly in each set was a pure species individual or a hybrid individual. "Suboccidentalis" refers to a pure species Drosophila suboccidentalis individual. "Occidentalis" refers to a pure species Drosophila occidentalis individual. "Hybrid(OxS)" refers to a hybrid individual generated by crossing a Drosophila occidentalis female to a Drosophila suboccidentalis male. "Hybrid(SxO)" refers to a hybrid individual generated by crossing a Drosophila suboccidentalis female to a Drosophila occidentalis male.Male Fertility F1 Hybrids.txtPure Species Latency to MateThis file contains data from the paper entitled "Asymmetrical sexual isolation but no postmating isolation between the closely related species Drosophila suboccidentalis and Drosophila occidentalis". This specific file contains data detailing the latency to copulation between pure species individuals (Supplemental Figure 2). Each row represents a single pair of flies involved in a no-choice mate trial that successfully copulated within the allotted time frame. The latency to copulation (measured in minutes) for each pair is recorded in the column titled "Latency". The "Female_Species" column indicates the species of female in each pairing. The "Male_Species" column indicates the species of male in each pairing. "Suboccidentalis" refers to a pure Drosophila suboccidentalis individual. "Occidentalis" refers to a pure Drosophila occidentalis individual.Hybrid Individual Mating LatencyThis file contains data from the paper entitled "Asymmetrical sexual isolation but no postmating isolation between the closely related species Drosophila suboccidentalis and Drosophila occidentalis". This specific file contains data detailing the latency to copulation between pure species individuals (Supplemental Figure 3). Each row represents a single pair of flies involved in a no-choice mate trial that successfully copulated within the allotted time frame. The latency to copulation (measured in minutes) for each pair is recorded in the column titled "Latency". The "Female_Type" column indicates whether the female fly in each pairing was a pure species individual or a hybrid individual. The "Male_Type" column indicates whether the male fly in each pairing was a pure species individual or a hybrid individual. "Suboccidentalis" refers to a pure species Drosophila suboccidentalis individual. "Occidentalis" refers to a pure species Drosophila occidentalis individual. "Hybrid(OxS)" refers to a hybrid individual generated by crossing a Drosophila occidentalis female to a Drosophila suboccidentalis male. "Hybrid(SxO)" refers to a hybrid individual generated by crossing a Drosophila suboccidentalis female to a Drosophila occidentalis male.Hybrid Mating Latency.txtHybrid Mating RatesThis file contains data from the paper entitled "Asymmetrical sexual isolation but no postmating isolation between the closely related species Drosophila suboccidentalis and Drosophila occidentalis". This specific file contains data detailing mating rates between hybrid and pure species individuals (Figure 2 from the paper). Each row represents a single pair of flies that were involved in a no-choice mate trial. A "1" in the "Mated(1=Yes)" column represents a pair of flies that successfully copulated within the allotted time frame. A "0" in this column indicated that the pair failed to copulate. The "Female_Type" column indicates whether the female fly in each pairing was a pure species individual or a hybrid individual. The "Male_Type" column indicates whether the male fly in each pairing was a pure species individual or a hybrid individual. "Suboccidentalis" refers to a pure species Drosophila suboccidentalis individual. "Occidentalis" refers to a pure species Drosophila occidentalis individual. "Hybrid(OxS)" refers to a hybrid individual generated by crossing a Drosophila occidentalis female to a Drosophila suboccidentalis male. "Hybrid(SxO)" refers to a hybrid individual generated by crossing a Drosophila suboccidentalis female to a Drosophila occidentalis male