intraspecific variability
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2022 ◽  
Vol 4 ◽  
Author(s):  
Matthew J. Hecking ◽  
Jenna M. Zukswert ◽  
John E. Drake ◽  
Martin Dovciak ◽  
Julia I. Burton

Trait-based analyses provide powerful tools for developing a generalizable, physiologically grounded understanding of how forest communities are responding to ongoing environmental changes. Key challenges lie in (1) selecting traits that best characterize the ecological performance of species in the community and (2) determining the degree and importance of intraspecific variability in those traits. Recent studies suggest that globally evident trait correlations (trait dimensions), such as the leaf economic spectrum, may be weak or absent at local scales. Moreover, trait-based analyses that utilize a mean value to represent a species may be misleading. Mean trait values are particularly problematic if species trait value rankings change along environmental gradients, resulting in species trait crossover. To assess how plant traits (1) covary at local spatial scales, (2) vary across the dominant environmental gradients, and (3) can be partitioned within and across taxa, we collected data on 9 traits for 13 tree species spanning the montane temperate—boreal forest ecotones of New York and northern New England. The primary dimension of the trait ordination was the leaf economic spectrum, with trait variability among species largely driven by differences between deciduous angiosperms and evergreen gymnosperms. A second dimension was related to variability in nitrogen to phosphorous levels and stem specific density. Levels of intraspecific trait variability differed considerably among traits, and was related to variation in light, climate, and tree developmental stage. However, trait rankings across species were generally conserved across these gradients and there was little evidence of species crossover. The persistence of the leaf economics spectrum in both temperate and high-elevation conifer forests suggests that ecological strategies of tree species are associated with trade-offs between resource acquisition and tolerance, and may be quantified with relatively few traits. Furthermore, the assumption that species may be represented with a single trait value may be warranted for some trait-based analyses provided traits were measured under similar light levels and climate conditions.


Author(s):  
Shannon Hunter ◽  
Rebecca McDougal ◽  
Nari Williams ◽  
Peter Scott

AbstractPhosphite is used to control and manage many phytophthora diseases in horticultural systems worldwide and natural ecosystems in Australia, Africa, New Zealand and parts of Northern America and Europe. Phosphite does not kill Phytophthora species, but inhibits growth while also stimulating host defence responses. Phytophthora species differ in their underlying tolerance to phosphite and isolates have been shown to acquire tolerance after prolonged exposure. Intra- and inter-specific variability in phosphite sensitivity is of interest to determine the efficacy and sustainability of phosphite for the treatment of phytophthora diseases, which continue to spread globally. Seven Phytophthora species were tested for their sensitivity to phosphite in vitro in a mycelial growth experiment. Phytophthora agathidicida was the species most sensitive to phosphite, being inhibited by 98.7% on average at the lowest phosphite treatment (15 µg/mL phosphite), followed by P. aleatoria, P. cinnamomi, P. pluvialis, P. multivora, P. kernoviae and P. citricola. Huge intraspecific variability was observed with P. kernoviae, which raises the question of whether diseases caused by P. kernoviae such as phytophthora needle blight of Pinus radiata could be managed effectively with phosphite. Further work is required to determine the phosphite sensitivity of different introduced and native Phytophthora species growing in key hosts and whether tolerance observed in vitro is also expressed in vivo.


2021 ◽  
Author(s):  
Piotr Olszewski ◽  
Radosław Puchałka ◽  
Piotr Sewerniak ◽  
Marcin Koprowski ◽  
Werner Ulrich

Abstract Increasing evidence points to the major impact of intraspecific variability in species characteristics on community assembly. Contrasting theories predict that high trait variability might either steepening dominance orders or promote diversity. Here, we try to test these predictions with understorey plants in a Polish mixed temperate forest. We focus on four important traits (leaf dry mass LDW, plant height SH, specific leaf area SLA, and number of flowers NF) of the small balsam Impatiens parviflora, the dominant species in this forest system. We relate trait variability to community species richness and abundances, as well as to soil characteristics. The variance – mean relationships of LDW, LH, and NF, but not of SLA, closely followed power functions with slopes > 1.5. Contrary to theory, abundances but not species richness of non-I. parviflora species significantly decreased within increasing variance in I. parviflora trait expression. High trait variability prevailed a higher species richness. Trait variability did not significantly influence species composition and was not significantly correlated with soil characteristics. Our results emphasis the need to study trait variability in terms of appropriate statistical standards as provided by the allometric variance - mean relationship. We argue that an individual based study of local trait variability might return important insights into the composition and assembly of local communities.


2021 ◽  
Vol 87 ◽  
pp. 267-289
Author(s):  
Cristina Vasiliţa ◽  
Ovidiu Alin Popovici ◽  
Elijah Talamas ◽  
Norman Johnson ◽  
Lubomir Masner ◽  
...  

The monotypic genus Latonius Kononova, 1982 (Platygastroidea, Scelionidae), was described from a single female specimen collected in southern Ukraine. It somewhat resembles Trissolcus Ashmead but has a distinctive claval formula. The only species in the genus, Latonius planus Kononova, 1982, is lacking any details regarding biology, sexual dimorphism, intraspecific variability, or distribution. Based on recently collected specimens the present study clarifies the position of Latonius within the Telenominae, provides a comprehensive description accompanied by high quality images, and compares Latonius and Trissolcus. Five molecular markers were amplified, and sequences of L. planus were analyzed using a data set for the molecular phylogeny of Telenominae (Taekul et al. 2014) and a molecular phylogeny of Trissolcus (Talamas et al. 2019). We dissected the metasoma, tarsi, antennae, and ovipositor and performed SEM imaging. The genera Latonius and Ioseppinella Mineo, O’Connor & Ashe, 2010, are treated as junior synonyms of Trissolcus and the type species of Latonius and Ioseppinella are considered to be conspecific (syn. nov.).


Diversity ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 3
Author(s):  
Carlo Maria Cusaro ◽  
Carolina Grazioli ◽  
Francesco Zambuto ◽  
Enrica Capelli ◽  
Maura Brusoni

Echinochloa crus-galli (L.) P. Beauv. (barnyardgrass) is one of the most noxious weeds infesting Italian rice fields. It is characterized by high genetic intraspecific variability and has developed resistance to several classes of herbicides. The aim of our study was to assess, for the first time in Italy, the genetic diversity in E. crus-galli from differently managed rice fields in the Lombardy region (Northern Italy) using eight specific SSR markers. To this purpose, an amplification protocol was optimized, testing different DNA concentrations, PCR mixtures, and temperatures. A total of 48 alleles were identified in 144 samples. SSR fingerprint analysis using R 3.6.3 software (poppr, polysat, and StAMPP) allowed us to handle SSRs as codominant and polyploid data. The results suggested that genetic richness and diversity were high. The analysis of molecular variance (AMOVA) indicated that genetic variation exists mainly between agronomic managements (47.23%) and among populations (37.01%). Hierarchical clustering and PCoA were in concordance with the identification of four distinct genetic groups. Our results confirm that SSR markers represent a valuable and affordable tool for the assessment of E. crus-galli genetic diversity and would grant useful information to plan more targeted, effective, and sustainable control strategies against barnyardgrass. The improved methodology applied here allowed us to assess the genetic variability of an allo-hexaploid species without information loss and biased results.


Agriculture ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1271
Author(s):  
Sandra Hilário ◽  
Liliana Santos ◽  
Artur Alves

Blueberries (Vaccinium corymbosum) are widely cultivated worldwide and largely consumed due to their known antioxidant and medicinal properties. Although Diaporthe species have been documented in Portugal as causal agents of blueberry twig blight and dieback, there is still scarce information on the species that cause these symptoms. Moreover, Diaporthe vaccinii, recently synonymized with D. eres, has been considered a concern to blueberry production worldwide. However, the current knowledge about its impact on blueberries remains unclear. The diversity of Diaporthe species associated with diseased blueberry plants were assessed through a national survey. A multilocus sequence analysis of the rDNA internal transcribed spacer (ITS) region, the translation elongation factor 1-alpha (tef1-α), β-tubulin (tub2), calmodulin (cal) and histone 3 (his3) genes unveiled the presence of Diaporthe ambigua, D. amygdali, D. crousii, D. foeniculina, D. hybrida, D. leucospermi, D. malorum and D. rudis. Moreover, all species were fully characterized based on a detailed morphological description. Diaporthe amygdali, D. hybrida, D. leucospermi and D. malorum are reported for the first time on diseased blueberries in Portugal. Results show that D. eres exhibited a high level of intraspecific variability within isolates, given that the strain CBS 160.32 might be a minor pathogen on blueberry plants, whereas CAA829 was revealed to be the most aggressive. Overall, this study also demonstrates that Diaporthe amygdali and D. eres may be two of the most aggressive species to blueberry plants. This study improves our understanding of the Diaporthe species and it’s causing of dieback and twig blight on Portuguese blueberry orchards. Additionally, the identification of these pathogens represents crucial information for blueberry producers to apply appropriate phytosanitary measures, as well as offering new insights into the potential pathogenicity of D. eres on this host.


Author(s):  
Débora E Moriconi ◽  
Catarina Macedo-Lopes ◽  
Adriana Sartorio ◽  
M Patricia Juárez ◽  
Juan R Girotti ◽  
...  

Abstract The Triatoma sordida subcomplex traditionally included four triatomine species, T. sordida, Triatoma garciabesi, Triatoma guasayana, and Triatoma patagonica, distributed in the Southern Cone of South America. These species have a large intraspecific variability together with an overall similarity, making difficult to establish their taxonomic status. Many cytogenetic, morphometric, and molecular markers have been applied to address this. Recent studies have posed concerns on the inclusion of T. guasayana and T. patagonica within the subcomplex. Also, T. sordida from Argentina has been designed as a new species, Triatoma rosai. Using the cuticular hydrocarbon pattern as chemotaxonomic marker, the relationships among several populations of these species were analyzed by capillary gas chromatography and linear discriminant analysis along 25 collection sites in Argentina, Bolivia, Brazil, and Paraguay. T. sordida and T. rosai populations were differentially clustered in two CHC-based groups: “Group 1” included T. sordida from Eastern Brazil, Eastern Paraguay, and the Bolivian populations from La Paz and Izozog G1; “Group 2” included T. rosai, and T. sordida from Izozog G2 (Bolivia), and Western Paraguay. Whereas T. garciabesi remained closely related to T. sordida and T. rosai, T. guasayana, and T. patagonica were clearly separated from the species of the T. sordida subcomplex. Our results agree with those from other several techniques suggesting that the taxonomy of the T. sordida subcomplex should be revised.


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