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Inskeep KA, Doellman MM, Powell THQ, Berlocher SH, Seifert NR, Hood GR, Ragland GJ, Meyers PJ, Feder JL. Divergent diapause life history timing drives both allochronic speciation and reticulate hybridization in an adaptive radiation of Rhagoletis flies. Mol Ecol 2021; 31:4031-4049. [PMID: 33786930 DOI: 10.1111/mec.15908] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 03/01/2021] [Accepted: 03/15/2021] [Indexed: 12/18/2022]
Abstract
Divergent adaptation to new ecological opportunities can be an important factor initiating speciation. However, as niches are filled during adaptive radiations, trait divergence driving reproductive isolation between sister taxa may also result in trait convergence with more distantly related taxa, increasing the potential for reticulated gene flow across the radiation. Here, we demonstrate such a scenario in a recent adaptive radiation of Rhagoletis fruit flies, specialized on different host plants. Throughout this radiation, shifts to novel hosts are associated with changes in diapause life history timing, which act as "magic traits" generating allochronic reproductive isolation and facilitating speciation-with-gene-flow. Evidence from laboratory rearing experiments measuring adult emergence timing and genome-wide DNA-sequencing surveys supported allochronic speciation between summer-fruiting Vaccinium spp.-infesting Rhagoletis mendax and its hypothesized and undescribed sister taxon infesting autumn-fruiting sparkleberries. The sparkleberry fly and R. mendax were shown to be genetically discrete sister taxa, exhibiting no detectable gene flow and allochronically isolated by a 2-month average difference in emergence time corresponding to host availability. At sympatric sites across the southern USA, the later fruiting phenology of sparkleberries overlaps with that of flowering dogwood, the host of another more distantly related and undescribed Rhagoletis taxon. Laboratory emergence data confirmed broadly overlapping life history timing and genomic evidence supported on-going gene flow between sparkleberry and flowering dogwood flies. Thus, divergent phenological adaptation can drive the initiation of reproductive isolation, while also enhancing genetic exchange across broader adaptive radiations, potentially serving as a source of novel genotypic variation and accentuating further diversification.
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Affiliation(s)
- Katherine A Inskeep
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Meredith M Doellman
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Thomas H Q Powell
- Department of Biological Sciences, Binghamton University (State University of New York), Binghamton, NY, USA
| | - Stewart H Berlocher
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Nicholas R Seifert
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Glen R Hood
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Gregory J Ragland
- Department of Integrative Biology, University of Colorado Denver, Denver, CO, USA
| | - Peter J Meyers
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Jeffrey L Feder
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
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Coding-Complete Genome Sequence of a Partitivirus Isolated from Pine Processionary Moth Eggs. Microbiol Resour Announc 2021; 10:10/8/e00071-21. [PMID: 33632856 PMCID: PMC7909081 DOI: 10.1128/mra.00071-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two coding-complete nucleotide sequences of a partitivirus (family Partitiviridae) were discovered in transcriptomic data sets obtained from eggs of the Lepidoptera Thaumetopoea pityocampa. Each segment encodes a single open reading frame, and these two segments are predicted to encode an RNA-dependent RNA polymerase and a coat protein, respectively. Two coding-complete nucleotide sequences of a partitivirus (family Partitiviridae) were discovered in transcriptomic data sets obtained from eggs of the Lepidoptera Thaumetopoea pityocampa. Each segment encodes a single open reading frame, and these two segments are predicted to encode an RNA-dependent RNA polymerase and a coat protein, respectively.
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