Umeå universitets logga

umu.sePublikationer
Ändra sökning
Avgränsa sökresultatet
1 - 8 av 8
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1. Connahs, Heidi
    et al.
    Aiello, Annette
    Van Bael, Sunshine
    Rodriguez-Castaneda, Genoveva
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Caterpillar abundance and parasitism in a seasonally dry versus wet tropical forest of Panama2011Ingår i: Journal of Tropical Ecology, ISSN 0266-4674, E-ISSN 1469-7831, Vol. 27, nr 1, s. 51-58Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rainfall seasonality can strongly influence biotic interactions by affecting host plant quality, and thus potentially regulating herbivore exposure to natural enemies. Plant defences are predicted to increase from dry to wet forests, rendering wet-forest caterpillars more vulnerable to parasitoids due to the slow-growth-high-mortality hypothesis. We collected and reared caterpillars from the understorey and trail edges of a wet forest and a seasonally dry forest to determine whether wet-forest caterpillars suffered a higher prevalence of parasitism and were less abundant than dry-forest caterpillars. In the two forests, caterpillar abundances (on average 8 h(-1)) and prevalence of parasitism (18%) were very similar regardless of feeding niche for both parasitism (27% versus 29% in shelter builders, and 16% versus 11% in external feeders) and caterpillar abundances (shelter builders: 1.42 versus 2.39, and external feeders: 8.27 versus 5.49 caterpillars h(-1)) in the dry and wet forests, respectively. A similar comparative analysis conducted in the canopy and understorey of the dry forest revealed a higher prevalence of parasitism in the canopy (43%) despite caterpillar densities similar to those in the understorey. Overall, shelter builders suffered higher parasitism than external feeders (32% versus 14.9%), and were attacked primarily by flies, whereas external feeders were more vulnerable to attack by parasitoid wasps.

  • 2. Godschalx, Adrienne L.
    et al.
    Rodriguez-Castaneda, Genoveva
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Rasmann, Sergio
    Contribution of different predator guilds to tritrophic interactions along ecological clines2019Ingår i: Current Opinion in Insect Science, ISSN 2214-5745, E-ISSN 2214-5753, Vol. 32, s. 104-109Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The strengths of interactions between plants, herbivores, and predators are predicted to relax with elevation. Despite the fundamental role predators play in tritrophic interactions, high-resolution experimental evidence describing predation across habitat gradients is still scarce in the literature and varies by predator. With this opinion paper, we look at how tritrophic strength of systems including different vertebrate and invertebrate predator guilds changes with elevation. Specifically, we focus on how birds, ants, parasitoids, and nematodes exert top-down pressure as predators and propose ways, in which each group could be better understood through elevational gradient studies. We hope to enrich future perspectives for disentangling the different biotic and abiotic factors underlying predator-mediated trophic interactions in a diversity of habitats.

  • 3.
    Jansson, Roland
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Rodriguez-Castaneda, Genoveva
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Harding, Larisa E.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    What can multiple phylogenies say about the latitudinal diversity gradient?: a new look at the tropical conservatism, out of the tropics, and diversification rate hypotheses2013Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 67, nr 6, s. 1741-1755Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We reviewed published phylogenies and selected 111 phylogenetic studies representing mammals, birds, insects, and flowering plants. We then mapped the latitudinal range of all taxa to test the relative importance of the tropical conservatism, out of the tropics, and diversification rate hypotheses in generating latitudinal diversity gradients. Most clades originated in the tropics, with diversity peaking in the zone of origin. Transitions of lineages between latitudinal zones occurred at 16-22% of the tree nodes. The most common type of transition was range expansions of tropical lineages to encompass also temperate latitudes. Thus, adaptation to new climatic conditions may not represent a major obstacle for many clades. These results contradict predictions of the tropical conservatism hypothesis (i.e., few clades colonizing extratropical latitudes), but support the out-of-the-tropics model (i.e., tropical originations and subsequent latitudinal range expansions). Our results suggest no difference in diversification between tropical and temperate sister lineages; thus, diversity of tropical clades was not explained by higher diversification rates in this zone. Moreover, lineages with latitudinal stasis diversified more compared to sister lineages entering a new latitudinal zone. This preserved preexisting diversity differences between latitudinal zones and can be considered a new mechanism for why diversity tends to peak in the zone of origin.

  • 4.
    Rodriguez-Castaneda, Genoveva
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Dyer, Lee A
    Brehm, Gunnar
    Connahs, Heidi
    Forkner, Rebecca E
    Walla, Thomas R
    Tropical forests are not flat: how mountains affect herbivore diversity2010Ingår i: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 13, nr 11, s. 1348-1357Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ecologists debate whether tropical insect diversity is better explained by higher plant diversity or by host plant species specialization. However, plant-herbivore studies are primarily based in lowland rainforests (RF) thus excluding topographical effects on biodiversity. We examined turnover in Eois (Geometridae) communities across elevation by studying elevational transects in Costa Rica and Ecuador. We found four distinct Eois communities existing across the elevational gradients. Herbivore diversity was highest in montane forests (MF), whereas host plant diversity was highest in lowland RF. This was correlated with higher specialization and species richness of Eois/host plant species we found in MF. Based on these relationships, Neotropical Eois richness was estimated to range from 313 (only lowland RF considered) to 2034 (considering variation with elevation). We conclude that tropical herbivore diversity and diet breadth covary significantly with elevation and urge the inclusion of montane ecosystems in host specialization and arthropod diversity estimates.

  • 5.
    Rodriguez-Castaneda, Genoveva
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Forkner, Rebecca E.
    Tepe, Eric J.
    Gentry, Grant L.
    Dyer, Lee A.
    Weighing defensive and nutritive roles of ant mutualists across a tropical altitudinal gradient2011Ingår i: Biotropica, ISSN 0006-3606, E-ISSN 1744-7429, Vol. 43, nr 3, s. 343-350Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The diversity of mutualistic interactions influences many ecological components of community structure, including biodiversity and ecosystem stability. However, mutualistic interactions are not well resolved because of a historical bias toward examining antagonistic interactions. Here we examine both antagonistic and facilitative interactions between tropical plants and arthropods by characterizing the biotic interactions between a common myrmecophytic shrub, Piper immutatum Trel. (Piperaceae), the ants hosted by this plant, Pheidole sp. (Formicidae: Myrmicinae), and their associated communities of herbivorous and predatory arthropods. To determine if ant mutualists affect the altitudinal distribution of Neotropical myrmecophytes, P. immutatum interactions with arthropods were quantified across a tropical elevational gradient. Piper immutatum was most abundant in lower montane forests (1000-1600 m asl) and disappeared above 1600 m asl, and colonies of Pheidole sp. inhabited 90 percent of the sampled plants. The myrmecophyte was then transplanted within and beyond its altitudinal range, excluding ants from half of the transplanted plants. Plant survival was affected primarily by elevation, with only 20 percent surviving above 1600 m asl. Ant exclusion did not significantly affect plant mortality. Nevertheless, ant colony size did affect both herbivory and nutrient availability for surviving P. immutatum, with nutrient availability having a stronger effect than antiherbivore defense on growth and biomass. This approach of studying the contributions of ant mutualisms across the myrmecohpyte's habitat range yields an improved picture of the role of mutualistic interactions in determining community structure.

  • 6.
    Rodriguez-Castaneda, Genoveva
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Univ Texas Austin, Sect Integrat Biol, 205 W 24th St, Austin, TX 78712 USA.
    Hof, Anouschka R.
    Jansson, Roland
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    How bird clades diversify in response to climatic and geographic factors2017Ingår i: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 20, nr 9, s. 1129-1139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    While the environmental correlates of global patterns in standing species richness are well understood, it is poorly known which environmental factors promote diversification (speciation minus extinction) in clades. We tested several hypotheses for how geographic and climatic variables should affect diversification using a large dataset of bird sister genera endemic to the New World. We found support for the area, evolutionary speed, environmental predictability and climatic stability hypotheses, but productivity and topographic complexity were rejected as explanations. Genera that had accumulated more species tend to occupy wider niche space, manifested both as occurrence over wider areas and in more habitats. Genera with geographic ranges that have remained more stable in response to glacial-interglacial changes in climate were also more species rich. Since many relevant explanatory variables vary latitudinally, it is crucial to control for latitude when testing alternative mechanistic explanations for geographic variation in diversification among clades.

  • 7.
    Rodríguez-Castañeda, Genoveva
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Ecology and Evolution Department, Stony Brook University, Stony Brook, NY, USA.
    The world and its shades of green: a meta-analysis on trophic cascades across temperature and precipitation gradients2013Ingår i: Global Ecology and Biogeography, ISSN 1466-822X, E-ISSN 1466-8238, Vol. 22, nr 1, s. 118-130Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aim: To assess effects of current global temperature and precipitation gradients on the trophic function of plant-herbivore-predator interactions. Specifically, I study effects of climatic gradients on factors that control herbivore abundances: top-down, bottom-up trophic cascades and plant defences. I include predictions of climate change on shifts in trophic function, under the assumption that temperature and precipitation affect the physiology and performance of plants, herbivores and predators.

    Location: Global.

    Methods: A search of the relevant experiments on trophic interactions was conducted using the Web of Science and Scielo databases. Strength of trophic interactions from each experiment was studied by the calculation of the log ratio effect size (Ln R) of the control and experimental means. Each study was georeferenced and mean annual temperature (MAT) and total annual precipitation (TAP) were determined for each study location. Effect size of trophic interaction studies across the world were correlated with these environmental variables.

    Results: In total, 387 effect sizes were extracted from the literature. With the exception of bottom-up trophic cascades, trophic interactions and factors controlling herbivore abundance exhibited significant linear or quadratic relationships with either temperature or precipitation gradients: plant growth, predation and the effect of plant defence on herbivores increased with temperature. In contrast, plant growth and herbivory increased with precipitation across ecosystems. Finally, top-down trophic cascades increased towards the extremes of MAT and TAP gradients.

    Main conclusions: This study shows climatic gradients not only affect species geographic distributions and physiological tolerance but also the strength of their trophic functionality. This is especially true for the main biotic controls of herbivore populations (i.e. predation, top-down trophic cascades and plant defences). These results suggest future climate change will cause shifts in the strength of trophic interactions, resulting in increased or reduced population control of herbivores across global ecosystems.

  • 8. Wilson, J. S.
    et al.
    Forister, M. L.
    Dyer, L. A.
    O'Connor, J. M.
    Burls, K.
    Feldman, C. R.
    Jaramillo, M. A.
    Miller, J. S.
    Rodriguez-Castaneda, Maria Genoveva
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Tepe, E. J.
    Whitfield, J. B.
    Young, B.
    Host conservatism, host shifts and diversification across three trophic levels in two Neotropical forests2012Ingår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, nr 3, s. 532-546Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hostparasite systems have been models for understanding the connection between shifts in resource use and diversification. Despite theoretical expectations, ambiguity remains regarding the frequency and importance of host switches as drivers of speciation in herbivorous insects and their parasitoids. We examine phylogenetic patterns with multiple genetic markers across three trophic levels using a diverse lineage of geometrid moths (Eois), specialist braconid parasitoids (Parapanteles) and plants in the genus Piper. Hostparasite associations are mapped onto phylogenies, and levels of cospeciation are assessed. We find nonrandom patterns of host use within both the moth and wasp phylogenies. The mothplant associations in particular are characterized by small radiations of moths associated with unique host plants in the same geographic area (i.e. closely related moths using the same host plant species). We suggest a model of diversification that emphasizes an interplay of factors including host shifts, vicariance and adaptation to intraspecific variation within hosts.

1 - 8 av 8
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf