Multiple plant traits shape the genetic basis of herbivore community assembly

1. Community genetics research has posited a genetic basis to the assembly of ecological communities. For arthropod herbivores in particular, there is strong support that genetic variation in host plants is a key factor shaping their diversity and composition. However, the specific plant phenotypes underlying herbivore responses remain poorly explored for most systems. 2. We address this knowledge gap by examining the influence of both genetic and phenotypic variation in a dominant host-plant species, Salix hookeriana, on its associated arthropod herbivore community in a common garden experiment. Specifically, we surveyed herbivore responses among five different arthropod feeding guilds to 26 distinct S. hookeriana genotypes. Moreover, we quantified the heritability of a suite of plant traits that determine leaf quality (e.g. phenolic compounds, trichomes, specific leaf area, C : N) and whole-plant architecture, to identify which traits best accounted for herbivore community responses to S. hookeriana genotype. 3. We found that total herbivore abundance and community composition differed considerably among S. hookeriana genotypes, with strong and independent responses of several species and feeding guilds driving these patterns. We also found that leaf phenolic chemistry displayed extensive heritable variation, whereas leaf physiology and plant architecture tended to be less heritable. Of these traits, herbivore responses were primarily associated with leaf phenolics and plant architecture; however, different herbivore species and feeding guilds were associated with different sets of traits. Despite our thorough trait survey, plant genotype remained a significant predictor of herbivore responses in most trait association analyses, suggesting that unmeasured host-plant characteristics and/or interspecific interactions were also contributing factors. 4. Taken together, our results support that the genetic basis of herbivore community assembly occurs through a suite of plant traits for different herbivore species and feeding guilds. Still, identifying these phenotypic mechanisms requires measuring a broad range of plant traits and likely further consideration of how these traits affect interspecific interactions.Fil: Barbour, Matthew A.. University Of British Columbia; CanadáFil: Rodriguez Cabal, Mariano Alberto. University Of British Columbia; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Wu, Elizabeth T.. Humboldt State University; Estados UnidosFil: Julkunen Tiitto, Riitta. University of Eastern Finland; FinlandiaFil: Ritland, Carol E.. University Of British Columbia; CanadáFil: Miscampbell, Allyson E.. University Of British Columbia; CanadáFil: Jules, Erik S.. Humboldt State University; Estados UnidosFil: Crutsinger, Gregory M.. University Of British Columbia; Canad

Molecular approaches to systematic problems in parasitic nematodes : ribosomol DNA variation within cystidicola spp. (Nematoda: Habronematoidea) and the superfamily dracunculoidea

Morphological characters are traditionally used in nematode systematics, however, morphological convergence and marginal differences between close relatives can obscure species diversity and confound taxonomic studies. This thesis applies molecular approaches to systematic problems in two groups of parasitic nematodes where morphological data is ambiguous. Ribosomal DNA (rDNA) variable regions such as the first and second internal transcribed spacers (ITS-1 and ITS-2), and the D3 expansion loop of the large subunit have consistently distinguished nematode species and provided a limited basis for phylogenetic inference between close relatives. I assess rDNA variation within Cystidicola spp. (Nematoda; Habronematoidea) and the superfamily Dracunculoidea to examine species diversity in both groups, and phylogenetic relationships in the Dracunculoidea. Phenotypic variation in Cystidicola spp. suggests unresolved variation within the genus. Distinct life histories, host ranges, reproductive strategies, and adult and egg morphologies define the two recognized Cystidicola spp. Variable host specificity and egg morphology in Cystidicola farionis is difficult to interpret and could reflect genetic species-level variation. I sequenced four rDNA regions (ITS-1, ITS-2, 5.8S, D3) from Cystidicola spp. isolates from a total of seven host species and nine locations in Ontario (ONT), British Columbia (BC) and Finland (FIN). The ITS-1, 5.8S, and D3 regions displayed no inter or intraspecific variation. Two ITS-2 types were identified which differed at four nucleotide positions: the ITS-2 from C. farionis (BC) and C. stigmatura was identical and 365bp long; the ITS-2 from ONT and FIN C. farionis was identical and 368bp long. No relationship between egg morphology and genetic variation was apparent. ITS-2 differences between morphologically distinct C. farionis (ONT and FIN) and C. stigmatura were expected but comparison of this region among C. farionis isolates produced a surprising result. The ITS-2 distinguishes C. farionis (BC) from C. farionis (ONT and FIN) and suggests a closer relationship between C. farionis (BC) and C. stigmatura. Morphological resemblance among close relatives and a lack of phylogenetically informative characters in the superfamily Dracunculoidea reiterates this need for more precise taxonomic markers. I examined the D3 and ITS-2 regions from a total of nine dracunculoid species to distinguish cryptic species (e.g. Philonema spp.), place unidentified nematodes within the current classification system, and infer phylogenetic relationships within dracunculoid families (e.g. the Philometridae and Guyanemidae). I sequenced the D3 of two dracunculoid species, Philometroides huronensis and an unidentified nematode from Eopsetta exilis, adding these to an existing D3 data set of seven dracunculoids and sequenced the ITS-2 from all nine species. These regions varied in their ability to distinguish close relatives. The D3 region distinguishes Philonema agubernaculum and P. oncorhynchi but not Cystidicola spp. whereas the ITS-2 is identical in the former taxa and distinct in the latter. Both ITS-2 and D3 data supported previous suggestions that the family Philometridae may be artificial, and that members of the Guyanemidae are affiliated with some philometrids (e.g. Philonema spp.).Science, Faculty ofZoology, Department ofGraduat

Molecular phylogeny of an ancient rodent family (Aplodontiidae)

The family Aplodontiidae contains a single, monotypic extant genus, Aplodontia (mountain beaver), which was first described by Rafinesque in 1817. Phylogenetic studies have shown that it is the sister lineage to squirrels. Aplodontia rufa is endemic to the Pacific Northwest and ranges from central California to British Columbia, Canada. Currently, 7 described subspecies are recognized based on morphological taxonomic studies. In this study, mitochondrial and nuclear genes were sequenced to infer molecular phylogenies of A. rufa. One of the goals of this study was to use molecular data to test the current taxonomic hypothesis based on morphology. Another goal was to incorporate geographic information to elucidate distributions of major clades. Our results support the previously held subspecies designations based on morphological taxonomy, with 1 main exception: we determined that within A. rufa, the subspecies A. rufa rainieri and A. rufa rufa north of the Columbia River represent a single lineage and should revert to the name A. rufa olympica. Although we revised geographic boundaries for some groups (A. r. rufa, A. r. olympica, and A. r. pacifica), only the conservation status and management of A. r. olympica (previously 2 subspecies) in Canada may be affected. Our findings support the continued conservation efforts for the isolated and endangered lineages present in coastal California

Data from: Molecular phylogeny of an ancient rodent family (Aplodontiidae)

The family Aplodontiidae contains a single, monotypic extant genus, Aplodontia (mountain beaver), which was 1st described by Rafinesque in 1817. Phylogenetic studies have shown that it is the sister lineage to squirrels. Aplodontia rufa is endemic to the Pacific Northwest and ranges from central California to British Columbia. Currently, 7 described subspecies are recognized based on morphological taxonomic studies. In this study, mitochondrial and nuclear genes were sequenced to infer molecular phylogenies of A. rufa. One of the goals of this study was to test the current taxonomic hypothesis based on morphology with molecular data. Another goal was to incorporate geographic information to elucidate distributions of major clades. Our results support the previously held subspecies designations based on morphological taxonomy, with 1 main exception: we determined that within A. rufa, the subspecies A. rufa rainieri and A. rufa rufa north of the Columbia River represent a single lineage and should revert to the name A. rufa olympica. Although we revised geographic boundaries for some groups (A. r. rufa, A. r. olympica, A. r. pacifica), only the conservation status and management of A. r. olympica (previously 2 subspecies) in Canada may be affected. Our findings support the continued conservation efforts for the isolated and endangered lineages present in coastal California

all nuc.TXT

BEAST input file:GHR nuclear DNA sequence

Appendix 3 CR 080612

Haplotype table control region mitochondrial DN

Appendix 1 cytb 1050bp 080612

Haplotype Table whole cytochrome b sequence

Data from: Multiple plant traits shape the genetic basis of herbivore community assembly

1. Community genetics research has posited a genetic basis to the assembly of ecological communities. For arthropod herbivores in particular, there is strong support that genetic variation in host plants is a key factor shaping their diversity and composition. However, the specific plant phenotypes underlying herbivore responses remain poorly explored for most systems. 2. We address this knowledge gap by examining the influence of both genetic and phenotypic variation in a dominant host-plant species, Salix hookeriana, on its associated arthropod herbivore community in a common garden experiment. Specifically, we surveyed herbivore responses among five different arthropod feeding guilds to 26 distinct S. hookeriana genotypes. Moreover, we quantified the heritability of a suite of plant traits that determine leaf quality (e.g. phenolic compounds, trichomes, specific leaf area, C : N) and whole-plant architecture, to identify which traits best accounted for herbivore community responses to S. hookeriana genotype. 3. We found that total herbivore abundance and community composition differed considerably among S. hookeriana genotypes, with strong and independent responses of several species and feeding guilds driving these patterns. We also found that leaf phenolic chemistry displayed extensive heritable variation, whereas leaf physiology and plant architecture tended to be less heritable. Of these traits, herbivore responses were primarily associated with leaf phenolics and plant architecture; however, different herbivore species and feeding guilds were associated with different sets of traits. Despite our thorough trait survey, plant genotype remained a significant predictor of herbivore responses in most trait association analyses, suggesting that unmeasured host-plant characteristics and/or interspecific interactions were also contributing factors. 4. Taken together, our results support that the genetic basis of herbivore community assembly occurs through a suite of plant traits for different herbivore species and feeding guilds. Still, identifying these phenotypic mechanisms requires measuring a broad range of plant traits and likely further consideration of how these traits affect interspecific interactions

cytb prior root stdev mean CA

BEAST inout file: Mitochondrial DNA cytochrome b sequence

Appendix 2 cytb 450bp 080612

Haplotype table partial cytochrome