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Hybridization and the spread of the apple maggot fly, Rhagoletis pomonella (Diptera: Tephritidae), in the northwestern United States.

Arcella T, Hood GR, Powell TH, Sim SB, Yee WL, Schwarz D, Egan SP, Goughnour RB, Smith JJ, Feder JL - Evol Appl (2015)

Bottom Line: Allele frequencies for seven microsatellites in R. pomonella were more 'R. zephyria-like' in central Washington, suggesting that genes conferring resistance to desiccation may be adaptively introgressing from R. zephyria.However, in only one case was the putatively introgressing allele from R. zephyria not found in R. pomonella in the eastern USA.Thus, many of the alleles changing in frequency may have been prestanding in the introduced R. pomonella population.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of Notre Dame Notre Dame, IN, USA.

ABSTRACT
Hybridization may be an important process interjecting variation into insect populations enabling host plant shifts and the origin of new economic pests. Here, we examine whether hybridization between the native snowberry-infesting fruit fly Rhagoletis zephyria (Snow) and the introduced quarantine pest R. pomonella (Walsh) is occurring and may aid the spread of the latter into more arid commercial apple-growing regions of central Washington state, USA. Results for 19 microsatellites implied hybridization occurring at a rate of 1.44% per generation between the species. However, there was no evidence for increased hybridization in central Washington. Allele frequencies for seven microsatellites in R. pomonella were more 'R. zephyria-like' in central Washington, suggesting that genes conferring resistance to desiccation may be adaptively introgressing from R. zephyria. However, in only one case was the putatively introgressing allele from R. zephyria not found in R. pomonella in the eastern USA. Thus, many of the alleles changing in frequency may have been prestanding in the introduced R. pomonella population. The dynamics of hybridization are therefore complex and nuanced for R. pomonella, with various causes and factors, including introgression for a portion, but not all of the genome, potentially contributing to the pest insect's spread.

No MeSH data available.


Related in: MedlinePlus

STRUCTURE bar plots for four paired sites at (A) St. Cloud Park; (B) Beacon Rock State Park; (C) Home Valley; and (D) Burbank/Walla Walla, WA, depicting posterior probabilities of individual R. pomonella black hawthorn fly genotypes (on left) and R. zephyria snowberry fly genotypes (on right) belonging to one of four genotypic classes: pure R. pomonella origin (black), pure R. zephyria (light gray), F1 hybrid (red), or backcross (blue), based on genotypes at 19 microsatellite loci. Bars along the x-axis represent individual flies.
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fig03: STRUCTURE bar plots for four paired sites at (A) St. Cloud Park; (B) Beacon Rock State Park; (C) Home Valley; and (D) Burbank/Walla Walla, WA, depicting posterior probabilities of individual R. pomonella black hawthorn fly genotypes (on left) and R. zephyria snowberry fly genotypes (on right) belonging to one of four genotypic classes: pure R. pomonella origin (black), pure R. zephyria (light gray), F1 hybrid (red), or backcross (blue), based on genotypes at 19 microsatellite loci. Bars along the x-axis represent individual flies.

Mentions: Despite the lack of a fixed difference, microsatellite allele frequencies differed sufficiently enough such that all nine R. zephyria and nine R. pomonella populations clustered distinctly and separately from one another with 100% bootstrap support in the neighbor-joining (NJ) network (Fig. 2). In addition, a blind STRUCTURE analysis conducted by combining flies from all nine paired sympatric sites gave a best fit of K = 2 across the PNW, corresponding to the species R. zephyria and R. pomonella (Table S4; Fig. S1 and S2). Similarly, a model of K = 2 was supported for each of the nine paired sites considered separately, representing the two taxa (see Fig. 3A–D for STRUCTURE plots for the St. Cloud Park, Beacon Rock State Park, Home Valley, and Burbank/Walla Walla, and Fig. S2 for STRUCTURE plots for all sites, and Table S5 for mean Ln Likelihoods).


Hybridization and the spread of the apple maggot fly, Rhagoletis pomonella (Diptera: Tephritidae), in the northwestern United States.

Arcella T, Hood GR, Powell TH, Sim SB, Yee WL, Schwarz D, Egan SP, Goughnour RB, Smith JJ, Feder JL - Evol Appl (2015)

STRUCTURE bar plots for four paired sites at (A) St. Cloud Park; (B) Beacon Rock State Park; (C) Home Valley; and (D) Burbank/Walla Walla, WA, depicting posterior probabilities of individual R. pomonella black hawthorn fly genotypes (on left) and R. zephyria snowberry fly genotypes (on right) belonging to one of four genotypic classes: pure R. pomonella origin (black), pure R. zephyria (light gray), F1 hybrid (red), or backcross (blue), based on genotypes at 19 microsatellite loci. Bars along the x-axis represent individual flies.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561572&req=5

fig03: STRUCTURE bar plots for four paired sites at (A) St. Cloud Park; (B) Beacon Rock State Park; (C) Home Valley; and (D) Burbank/Walla Walla, WA, depicting posterior probabilities of individual R. pomonella black hawthorn fly genotypes (on left) and R. zephyria snowberry fly genotypes (on right) belonging to one of four genotypic classes: pure R. pomonella origin (black), pure R. zephyria (light gray), F1 hybrid (red), or backcross (blue), based on genotypes at 19 microsatellite loci. Bars along the x-axis represent individual flies.
Mentions: Despite the lack of a fixed difference, microsatellite allele frequencies differed sufficiently enough such that all nine R. zephyria and nine R. pomonella populations clustered distinctly and separately from one another with 100% bootstrap support in the neighbor-joining (NJ) network (Fig. 2). In addition, a blind STRUCTURE analysis conducted by combining flies from all nine paired sympatric sites gave a best fit of K = 2 across the PNW, corresponding to the species R. zephyria and R. pomonella (Table S4; Fig. S1 and S2). Similarly, a model of K = 2 was supported for each of the nine paired sites considered separately, representing the two taxa (see Fig. 3A–D for STRUCTURE plots for the St. Cloud Park, Beacon Rock State Park, Home Valley, and Burbank/Walla Walla, and Fig. S2 for STRUCTURE plots for all sites, and Table S5 for mean Ln Likelihoods).

Bottom Line: Allele frequencies for seven microsatellites in R. pomonella were more 'R. zephyria-like' in central Washington, suggesting that genes conferring resistance to desiccation may be adaptively introgressing from R. zephyria.However, in only one case was the putatively introgressing allele from R. zephyria not found in R. pomonella in the eastern USA.Thus, many of the alleles changing in frequency may have been prestanding in the introduced R. pomonella population.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of Notre Dame Notre Dame, IN, USA.

ABSTRACT
Hybridization may be an important process interjecting variation into insect populations enabling host plant shifts and the origin of new economic pests. Here, we examine whether hybridization between the native snowberry-infesting fruit fly Rhagoletis zephyria (Snow) and the introduced quarantine pest R. pomonella (Walsh) is occurring and may aid the spread of the latter into more arid commercial apple-growing regions of central Washington state, USA. Results for 19 microsatellites implied hybridization occurring at a rate of 1.44% per generation between the species. However, there was no evidence for increased hybridization in central Washington. Allele frequencies for seven microsatellites in R. pomonella were more 'R. zephyria-like' in central Washington, suggesting that genes conferring resistance to desiccation may be adaptively introgressing from R. zephyria. However, in only one case was the putatively introgressing allele from R. zephyria not found in R. pomonella in the eastern USA. Thus, many of the alleles changing in frequency may have been prestanding in the introduced R. pomonella population. The dynamics of hybridization are therefore complex and nuanced for R. pomonella, with various causes and factors, including introgression for a portion, but not all of the genome, potentially contributing to the pest insect's spread.

No MeSH data available.


Related in: MedlinePlus