| 1. |
- Hambäck, Peter A., et al.
(författare)
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Bayesian species delimitation reveals generalist and specialist parasitic wasps on Galerucella beetles (Chrysomelidae) : sorting by herbivore or plant host
- 2013
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Ingår i: BMC Evolutionary Biology. - : BioMed Central. - 1471-2148. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: To understand the ecological and evolutionary consequences of species interactions in food webs necessitates that interactions are properly identified. Genetic analyses suggest that many supposedly generalist parasitoid species should rather be defined as multiple species with a more narrow diet, reducing the probability that such species may mediate indirect interactions such as apparent competition among hosts. Recent studies showed that the parasitoid Asecodes lucens mediate apparent competition between two hosts, Galerucella tenella and G. calmariensis, affecting both interaction strengths and evolutionary feedbacks. The same parasitoid was also recorded from other species in the genus Galerucella, suggesting that similar indirect effects may also occur for other species pairs. Methods: To explore the possibility of such interactions, we sequenced mitochondrial and nuclear genetic markers to resolve the phylogeny of both host and parasitoid and to test the number of parasitoid species involved. We thus collected 139 Galerucella larvae from 8 host plant species and sequenced 31 adult beetle and 108 parasitoid individuals. Results: The analysis of the Galerucella data, that also included sequences from previous studies, verified the five species previously documented as reciprocally monophyletic, but the Bayesian species delimitation for A. lucens suggested 3-4 cryptic taxa with a more specialised host use than previously suggested. The gene data analyzed under the multispecies coalescent model allowed us to reconstruct the species tree phylogeny for both host and parasitoid and we found a fully congruent coevolutionary pattern suggesting that parasitoid speciation followed upon host speciation. Conclusion: Using multilocus sequence data in a Bayesian species delimitation analysis we propose that hymenopteran parasitoids of the genus Asecodes that infest Galerucella larvae constitute at least three species with narrow diet breath. The evolution of parasitoid Asecodes and host Galerucella show a fully congruent coevolutionary pattern. This finding strengthens the hypothesis that the parasitoid in host search uses cues of the host rather than more general cues of both host and plant.
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| 2. |
- Kodandaramaiah, Ullasa, et al.
(författare)
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Investigating concordance among genetic data, subspecies circumscriptions and hostplant use in the nymphalid butterfly polygonia faunus
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:7, s. e41058-
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Tidskriftsartikel (refereegranskat)abstract
- Subspecies are commonly used taxonomic units to formally describe intraspecific geographic variation in morphological traits. However, the concept of subspecies is not clearly defined, and there is little agreement about what they represent in terms of evolutionary units, and whether they can be used as reliably useful units in conservation, evolutionary theory and taxonomy. We here investigate whether the morphologically well-characterized subspecies in the North American butterfly Polygonia faunus are supported by genetic data from mitochondrial sequences and eight microsatellite loci. We also investigate the phylogeographic structure of P. faunus and test whether similarities in host-plant use among populations are related to genetic similarity. Neither the nuclear nor the mitochondrial data corroborated subspecies groupings. We found three well defined genetic clusters corresponding to California, Arizona and (New Mexico+Colorado). There was little structuring among the remaining populations, probably due to gene flow across populations. We found no support for the hypothesis that similarities in host use are related to genetic proximity. The results indicate that the species underwent a recent rapid expansion, probably from two glacial refugia in western North America. The mitochondrial haplotype network indicates at least two independent expansion phases into eastern North America. Our results clearly demonstrate that subspecies in P. faunus do not conform to the structuring of genetic variation. More studies on insects and other invertebrates are needed to better understand the scope of this phenomenon. The results of this study will be crucial in designing further experiments to understand the evolution of hostplant utilization in this species.
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| 3. |
- Kodandaramaiah, Ullasa, et al.
(författare)
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Population structure in relation to host-plant ecology and Wolbachia infestation in the comma butterfly
- 2011
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 24:10, s. 2173-2185
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Tidskriftsartikel (refereegranskat)abstract
- Experimental work on Polygonia c-album, a temperate polyphagous butterfly species, has shown that Swedish, Belgian, Norwegian and Estonian females are generalists with respect to host-plant preference, whereas females from UK and Spain are specialized on Urticaceae. Female preference is known to have a strong genetic component. We test whether the specialist and generalist populations form respective genetic clusters using data from mitochondrial sequences and 10 microsatellite loci. Results do not support this hypothesis, suggesting that the specialist and generalist traits have evolved more than once independently. Mitochondrial DNA variation suggests a rapid expansion scenario, with a single widespread haplotype occurring in high frequency, whereas microsatellite data indicate strong differentiation of the Moroccan population. Based on a comparison of polymorphism in the mitochondrial data and sequences from a nuclear gene, we show that the diversity in the former is significantly less than that expected under neutral evolution. Furthermore, we found that almost all butterfly samples were infected with a single strain of Wolbachia, a maternally inherited bacterium. We reason that indirect selection on the mitochondrial genome mediated by a recent sweep of Wolbachia infection has depleted variability in the mitochondrial sequences. We also surmise that P. c-album could have expanded out of a single glacial refugium and colonized Morocco recently.
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| 4. |
- Kodandaramaiah, Ullasa, et al.
(författare)
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Validity of the subspecies paradigm - a case study of the nymphalid butterfly Polygonia faunus
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Ingår i: PLOS ONE. - 1932-6203.
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Tidskriftsartikel (refereegranskat)abstract
- Subspecies are commonly used taxonomic units to formally describe intraspecific geographic variation in morphological traits. However, the concept of subspecies is not clearly defined, and there is little agreement about what they represent in terms of evolutionary units, and whether they can be used as reliably useful units in conservation, evolutionary theory and taxonomy. Although the validity of subspecies has been tested using a multi-marker genetic approach in vertebrates, such studies have been rare in invertebrates. We here test the validity of well-characterized subspecies in the butterfly Polygonia faunus using a combination of mitochondrial sequences and eight microsatellites. We have also investigated the phylogeographic Structure of P. faunus and test whether similarities in host-plant use among populations is related to genetic similarity. Neither the nuclear nor the mitochondrial dataset corroborated subspecies groupings. We found three welldefined genetic clusters corresponding to California, Arizona and (New Mexico + Colorado). There was little structuring among the remaining populations, probably due to gene flow across populations. We found no support for the hypothesis that similarities in host use are related to genetic proximity. The results indicate that the species underwent a recent rapid expansion, probably from two glacial refugia in western North America. The mitochondrial haplotype network indicates at least two independent expansion phases into eastern North America. Ourresults clearly demonstrate that subspecies in P. faunus do not conform to the structuring of genetic variation. More studies on insects and other invertebrates are needed to understand how widespread this phenomenon is. Results in this study will be crucial in designing further experiments to understand the evolution of host plant utilization in this species.
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| 5. |
- Peña, Carlos, et al.
(författare)
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Higher level phylogeny of Satyrinae butterflies (Lepidoptera: Nymphalidae) based on DNA sequence data
- 2006
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 40:1, s. 29-49
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Tidskriftsartikel (refereegranskat)abstract
- We have inferred the first empirically supported hypothesis of relationships for the cosmopolitan butterfly subfamily Satyrinae. We used 3090 base pairs of DNA from the mitochondrial gene COI and the nuclear genes EF-1alpha and wingless for 165 Satyrinae taxa representing 4 tribes and 15 subtribes, and 26 outgroups, in order to test the monophyly of the subfamily and elucidate phylogenetic relationships of its major lineages. In a combined analysis, the three gene regions supported an almost fully resolved topology, which recovered Satyrinae as polyphyletic, and revealed that the current classification of suprageneric taxa within the subfamily is comprised almost completely of unnatural assemblages. The most noteworthy findings are that Manataria is closely related to Melanitini; Palaeonympha belongs to Euptychiina; Oressinoma, Orsotriaena and Coenonympha group with the Hypocystina; Miller's (1968). Parargina is polyphyletic and its components group with multiple distantly related lineages; and the subtribes Elymniina and Zetherina fall outside the Satyrinae. The three gene regions used in a combined analysis prove to be very effective in resolving relationships of Satyrinae at the subtribal and tribal levels. Further sampling of the taxa closely related to Satyrinae, as well as more extensive sampling of genera within the tribes and subtribes for this group will be critical to test the monophyly of the subfamily and establish a stronger basis for future biogeographical and evolutionary studies.
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| 6. |
- Wahlberg, Niklas, et al.
(författare)
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Timing major conflict between mitochondrial and nuclear genes in species relationships of Polygonia butterflies (Nymphalidae: Nymphalini)
- 2009
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 92:9
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Tidskriftsartikel (refereegranskat)abstract
- Background Major conflict between mitochondrial and nuclear genes in estimating species relationships is an increasingly common finding in animals. Usually this is attributed to incomplete lineage sorting, but recently the possibility has been raised that hybridization is important in generating such phylogenetic patterns. Just how widespread ancient and/or recent hybridization is in animals and how it affects estimates of species relationships is still not well-known. Results We investigate the species relationships and their evolutionary history over time in the genus Polygonia using DNA sequences from two mitochondrial gene regions (COI and ND1, total 1931 bp) and four nuclear gene regions (EF-1α, wingless, GAPDH and RpS5, total 2948 bp). We found clear, strongly supported conflict between mitochondrial and nuclear DNA sequences in estimating species relationships in the genus Polygonia. Nodes at which there was no conflict tended to have diverged at the same time when analyzed separately, while nodes at which conflict was present diverged at different times. We find that two species create most of the conflict, and attribute the conflict found in Polygonia satyrus to ancient hybridization and conflict found in Polygonia oreas to recent or ongoing hybridization. In both examples, the nuclear gene regions tended to give the phylogenetic relationships of the species supported by morphology and biology. Conclusion Studies inferring species-level relationships using molecular data should never be based on a single locus. Here we show that the phylogenetic hypothesis generated using mitochondrial DNA gives a very different interpretation of the evolutionary history of Polygonia species compared to that generated from nuclear DNA. We show that possible cases of hybridization in Polygonia are not limited to sister species, but may be inferred further back in time. Furthermore, we provide more evidence that Haldane's effect might not be as strong a process in preventing hybridization in butterflies as has been previously thought.
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| 7. |
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| 9. |
- Weingartner, Elisabet, et al.
(författare)
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Dynamics of host plant use and species diversity in Polygonia butterflies (Nymphalidae)
- 2006
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Ingår i: J Evol Biol. - 1010-061X. ; 19:2, s. 483-91
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Tidskriftsartikel (refereegranskat)abstract
- The ability of insects to utilize different host plants has been suggested to be a dynamic and transient phase. During or after this phase, species can shift to novel host plants or respecialize on ancestral ones. Expanding the range of host plants might also be a factor leading to higher levels of net speciation rates. In this paper, we have studied the possible importance of host plant range for diversification in the genus Polygonia (Nymphalidae, Nymphalini). We have compared species richness between sistergroups in order to find out if there are any differences in number of species between clades including species that utilize only the ancestral host plants ('urticalean rosids') and their sisterclades with a broader (or in some cases potentially broader) host plant repertoire. Four comparisons could be made, and although these are not all phylogenetically or statistically independent, all showed clades including butterfly species using other or additional host plants than the urticalean rosids to be more species-rich than their sisterclade restricted to the ancestral host plants. These results are consistent with the theory that expansions in host plant range are involved in the process of diversification in butterflies and other phytophagous insects, in line with the general theory that plasticity may drive speciation.
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