Comparative Body Size and Shape Analyses of F1 Hybrid<i>Rhagoletis pomonella</i>and<i>Rhagoletis zephyria</i>(Diptera: Tephritidae)

Yee, Wee L.; Chapman, Peter S.; Sheets, H. David

doi:10.1603/an13016

Cited by 3 publications

(2 citation statements)

References 31 publications

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“…In our study, we analyzed 38 R. pomonella , 26 R. mendax , and 35 R. zephyria in the geographic sample, and an additional 27 R. pomonella and 17 R. zephyria in the Beacon Rock sample. We also have not yet analyzed F1 hybrids between R. pomonella and R. zephyria ( Yee and Goughnour 2011 , Yee et al 2013 ), or backcross individuals. Work to expand the sample size and experiments to determine the outcomes given hybrid and introgressed individuals remains to be carried out.…”

Section: Discussionmentioning

confidence: 99%

Partial Ribosomal Nontranscribed Spacer Sequences DistinguishRhagoletis zephyria(Diptera: Tephritidae) From the Apple Maggot,R. pomonella

Smith

Brzezinski

Dziedziula

et al. 2022

Journal of Economic Entomology

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The apple maggot, Rhagoletis pomonella (Walsh), was introduced into the apple-growing regions of the Pacific Northwest in the U.S.A. during the past 60–100 yr. Apple maggot (larvae, puparia, and adults) is difficult to distinguish from its morphologically similar sister species, Rhagoletis zephyria Snow, which is native and abundant in the Pacific Northwest. While morphological identifications are common practice, a simple, inexpensive assay based on genetic differences would be very useful when morphological traits are unclear. Here we report nucleotide substitution and insertion–deletion mutations in the nontranscribed spacer (NTS) of the ribosomal RNA gene cistron of R. pomonella and R. zephyria that appear to be diagnostic for these two fly species. Insertion–deletion variation is substantial and results in a 49 base-pair difference in PCR amplicon size between R. zephyria and R. pomonella that can be scored using agarose gel electrophoresis. PCR amplification and DNA sequencing of 766 bp of the NTS region from 38 R. pomonella individuals and 35 R. zephyria individuals from across their geographic ranges led to the expected PCR fragments of approx. 840 bp and 790 bp, respectively, as did amplification and sequencing of a smaller set of 26 R. pomonella and 16 R. zephyria flies from a sympatric site in Washington State. Conversely, 633 bp mitochondrial COI barcode sequences from this set of flies were polyphyletic with respect to R. pomonella and R. zephyria. Thus, differences in NTS PCR products on agarose gels potentially provide a simple way to distinguish between R. pomonella and R. zephyria.

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Section: Discussionmentioning

confidence: 99%

Partial Ribosomal Nontranscribed Spacer Sequences DistinguishRhagoletis zephyria(Diptera: Tephritidae) From the Apple Maggot,R. pomonella

Smith

Brzezinski

Dziedziula

et al. 2022

Journal of Economic Entomology

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“…The snowberry fly is also distributed through the northern plains states, where R. pomonella is not present, and westward into the PNW, where it is native and co-occurs with R. pomonella . In central WA, R. zephyria is problematic to commercial apple growers because it is abundant and difficult to definitively distinguish morphologically from the rarer R. pomonella when trapped in monitoring surveys (Westcott 1982 ; Yee et al 2009 , 2011 , 2013 ). Due to the zero tolerance policy, misidentification of R. zephyria as R. pomonella is of concern because false positives can result in unnecessary quarantine measures being imposed at great cost to stakeholders, including growers and local and federal agencies (St. Jean et al 2013 ).…”

Section: Introductionmentioning

confidence: 99%

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

Arcella

Hood

Powell

et al. 2015

Evolutionary Applications

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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.

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Molecular Species Identification of Cryptic Apple and Snowberry Maggots (Diptera: Tephritidae) in Western and Central Washington

et al. 2013

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In Washington state, identification of the quarantine apple pest Rhagoletis pomonella (Walsh) is complicated by the presence of the cryptic species Rhagoletis zephyria Snow (Diptera: Tephritidae). Distinguishing the two flies is important because there is a zero tolerance policy for R. pomonella in apple production for export. Here, we attempt to distinguish the two species by scoring R. pomonella and R. zephyria populations from western and south-central Washington for a set of 11 nuclear markers, including four single nucleotide polymorphisms (SNPs) developed for rapid and inexpensive genotyping using Taqman real-time quantitative-polymerase chain reaction. We show that the four SNPs may be adequate in most cases for distinguishing whether a fly originated from apple or black hawthorn (the two major host plants for R. pomonella representing an economic risk) versus snowberry (the major host for R. zephyria, and not a commercial threat). However, directional introgression of R. zephyria alleles into R. pomonella can complicate the identification of flies of mixed ancestry based only on the four SNPs. Moreover, this problem is more acute in the sensitive apple-growing regions of central Washington where our results imply hybridization is common. Consequently, application of the four SNP quantitative-polymerase chain reaction assay can immediately assist ongoing apple maggot monitoring, while the development of additional genetic markers through next-generation sequencing would be valuable for increasing confidence in species identification and for assessing the threat posed by hybridization as R. pomonella further spreads into the more arid apple-growing regions of central Washington.

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Comparative Body Size and Shape Analyses of F1 HybridRhagoletis pomonellaandRhagoletis zephyria(Diptera: Tephritidae)

Cited by 3 publications

References 31 publications

Partial Ribosomal Nontranscribed Spacer Sequences DistinguishRhagoletis zephyria(Diptera: Tephritidae) From the Apple Maggot,R. pomonella

Partial Ribosomal Nontranscribed Spacer Sequences DistinguishRhagoletis zephyria(Diptera: Tephritidae) From the Apple Maggot,R. pomonella

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

Molecular Species Identification of Cryptic Apple and Snowberry Maggots (Diptera: Tephritidae) in Western and Central Washington

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