Acari and Collembola biodiversity in Canadian agricultural soils

2003 ◽  
Vol 83 (Special Issue) ◽  
pp. 279-288 ◽  
Author(s):  
V. M. Behan-Pelletier
Keyword(s):  
Population Structure ◽  
Key Words ◽  
Life Histories ◽  
Size Range ◽  
Agricultural Soils ◽  
Feeding Habits ◽  
Agricultural Practices ◽  
Ecological Studies ◽  
Research Challenges ◽  
Effective Use

In Canadian agricultural soils, mites (Acari) are the most diverse and abundant arthropods. In comparison with other arachnids, mites are notable for their small size, diverse feeding habits, often complex life histories, and the range of habitats in which they live. Collembola are also abundant and diverse in soil and litter, they are in the same size range as the Acari, and for that reason the two groups are often combined in soil ecological studies as “microarthropods ”. This paper provides a descriptive overview of the state of our knowledge on the taxonomy of these arthropods. It reviews the literature on biology and ecology of microarthropods in Canadian agroecosystems, especially on implications of various agricultural practices for their diversity and population structure. It discusses the research challenges in taxonomy and ecology to address effective use of this biodiversity in Canadian agroecosystems. Key words: Acari, Collembola, microarthropods, taxonomy, ecology

scholarly journals Using reliable predator identification to investigate feeding habits of Neotropical carnivores (Mammalia, Carnivora) in a deforestation frontier of the Brazilian Amazon

Mammalia ◽  
2019 ◽  
Vol 83 (5) ◽  
pp. 415-427 ◽  
Author(s):  
Flávia P. Tirelli ◽  
Thales R.O. de Freitas ◽  
Fernanda Michalski ◽  
Alexandre R. Percequillo ◽  
Eduardo Eizirik
Keyword(s):  
Feeding Habits ◽  
Brazilian Amazon ◽  
Ecological Studies ◽  
Accurate Identification ◽  
Predator Species ◽  
Non Invasive ◽  
Carnivore Species ◽  
Faecal Samples ◽  
Critical Requirement ◽  
Better Than

Abstract Accurate identification of predator species is a critical requirement to investigate their diet using faecal samples. We used non-invasive sampling and two methods of predator identification to investigate the diets of sympatric carnivores in a highly deforested region of the Brazilian Amazon. Of 108 scats, 81 could be identified at the species level using DNA sequencing and/or trichology. The former performed better than the latter (81.5% vs. 54.3% of the identified samples), and results were quite congruent (89.7% concordance in the 29 samples that could be assessed with both approaches). Nine species were identified, out of which four (crab-eating fox, ocelot, puma and jaguar) presented a sufficient number of samples to allow dietary analyses. The crab-eating fox was the most generalist (BA=0.92); ocelots focused on small- to medium-sized prey; pumas fed mostly on medium-sized items; and jaguars mostly targeted large-sized prey. A considerable overlap was observed between ocelots and pumas in all estimations (O=0.47–0.83). The presence of jaguars in the same region could be driving pumas to select medium- and small-sized prey. The results of this study highlight the importance of reliable predator identification and the need for in-depth ecological studies in areas where carnivore species are sympatric.

scholarly journals Mixed-Cropping Between Field Pea Varieties Alters Root Bacterial and Fungal Communities

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anthony Horner ◽  
Samuel S. Browett ◽  
Rachael E. Antwis
Keyword(s):  
Microbial Communities ◽  
Bacterial Communities ◽  
Crop Production ◽  
Agricultural Soils ◽  
Critical Role ◽  
Agricultural Practices ◽  
Microbial Interactions ◽  
Field Pea ◽  
Fungal Communities ◽  
Mixed Cropping

AbstractModern agricultural practices have vastly increased crop production but negatively affected soil health. As such, there is a call to develop sustainable, ecologically-viable approaches to food production. Mixed-cropping of plant varieties can increase yields, although impacts on plant-associated microbial communities are unclear, despite their critical role in plant health and broader ecosystem function. We investigated how mixed-cropping between two field pea (Pisum sativum L.) varieties (Winfreda and Ambassador) influenced root-associated microbial communities and yield. The two varieties supported significantly different fungal and bacterial communities when grown as mono-crops. Mixed-cropping caused changes in microbial communities but with differences between varieties. Root bacterial communities of Winfreda remained stable in response to mixed-cropping, whereas those of Ambassador became more similar to Winfreda. Conversely, root fungal communities of Ambassador remained stable under mixed-cropping, and those of Winfreda shifted towards the composition of Ambassador. Microbial co-occurrence networks of both varieties were stronger and larger under mixed-cropping, which may improve stability and resilience in agricultural soils. Both varieties produced slightly higher yields under mixed-cropping, although overall Ambassador plants produced higher yields than Winfreda plants. Our results suggest that variety diversification may increase yield and promote microbial interactions.

scholarly journals The Green Revolution shaped the population structure of the rice pathogen Xanthomonas oryzae pv. oryzae

2019 ◽  
Vol 14 (2) ◽  
pp. 492-505 ◽  
Author(s):  
Ian Lorenzo Quibod ◽  
Genelou Atieza-Grande ◽  
Eula Gems Oreiro ◽  
Denice Palmos ◽  
Marian Hanna Nguyen ◽  
...  
Keyword(s):  
Population Structure ◽  
Plant Pathogens ◽  
Crop Improvement ◽  
Green Revolution ◽  
Agricultural Practices ◽  
The Philippines ◽  
Xanthomonas Oryzae ◽  
Rice Varieties ◽  
Evolutionary Trajectory ◽  
The Impact

Abstract The impact of modern agriculture on the evolutionary trajectory of plant pathogens is a central question for crop sustainability. The Green Revolution replaced traditional rice landraces with high-yielding varieties, creating a uniform selection pressure that allows measuring the effect of such intervention. In this study, we analyzed a unique historical pathogen record to assess the impact of a major resistance gene, Xa4, in the population structure of Xanthomonas oryzae pv. oryzae (Xoo) collected in the Philippines in a span of 40 years. After the deployment of Xa4 in the early 1960s, the emergence of virulent pathogen groups was associated with the increasing adoption of rice varieties carrying Xa4, which reached 80% of the total planted area. Whole genomes analysis of a representative sample suggested six major pathogen groups with distinctive signatures of selection in genes related to secretion system, cell-wall degradation, lipopolysaccharide production, and detoxification of host defense components. Association genetics also suggested that each population might evolve different mechanisms to adapt to Xa4. Interestingly, we found evidence of strong selective sweep affecting several populations in the mid-1980s, suggesting a major bottleneck that coincides with the peak of Xa4 deployment in the archipelago. Our study highlights how modern agricultural practices facilitate the adaptation of pathogens to overcome the effects of standard crop improvement efforts.

scholarly journals The life histories and population dynamics of monogenean gill parasites of Trachurus trachurus (L.)

1962 ◽  
Vol 42 (3) ◽  
pp. 587-600 ◽  
Author(s):  
J. Llewellyn
Keyword(s):  
Coastal Waters ◽  
Life Histories ◽  
Feeding Habits ◽  
Limiting Factor ◽  
Trachurus Trachurus ◽  
Free Living ◽  
Sea Bottom ◽  
Second Year ◽  
Post Spawning ◽  
Gill Parasites

Gastrocotyle trachuri and Pseudaxine trachuri infect young Trachurus trachurus at Plymouth as soon as the 3- or 4-month-old adolescent fishes descend to the sea bottom in October. The parasites normally mature in 3 or 4 months, but, exceptionally, in about 1 month, and the life-span is normally no longer than 1 year. Trachurus specimens at the beginning of their second year pick up a largely new infection of parasites.G. trachuri and P. trachuri are much less frequent on 2- and 3-year-old specimens of Trachurus and probably occur only very rarely on still older fishes, the limiting factor being not an age-immunity but a post-spawning migration of the host from the concentration of free-living infective stages of the parasites in coastal waters.The parasites have adapted themselves to a seasonal change in the feeding habits of Trachurus by ceasing to produce larvae in anticipation of the summer disappearance of scad from the sea bottom in pursuit of pelagic food-organisms.

scholarly journals Root Proteomic Analysis of Two Grapevine Rootstock Genotypes Showing Different Susceptibility to Salt Stress

2020 ◽  
Vol 21 (3) ◽  
pp. 1076 ◽  
Author(s):  
Bhakti Prinsi ◽  
Osvaldo Failla ◽  
Attilio Scienza ◽  
Luca Espen
Keyword(s):  
Salt Stress ◽  
Abiotic Stress ◽  
Energy Metabolism ◽  
Agricultural Soils ◽  
Agricultural Practices ◽  
Limiting Factor ◽  
Protective Mechanisms ◽  
Biochemical Level ◽  
The Impact ◽  
First Time

Salinity represents a very limiting factor that affects the fertility of agricultural soils. Although grapevine is moderately susceptible to salinity, both natural causes and agricultural practices could worsen the impact of this abiotic stress. A promising possibility to reduce this problem in vineyards is the use of appropriate graft combinations. The responses of grapevine rootstocks to this abiotic stress at the root level still remain poorly investigated. In order to obtain further information on the multifaceted responses induced by salt stress at the biochemical level, in the present work we analyzed the changes that occurred under control and salt conditions in the root proteomes of two grapevine rootstock genotypes, M4 and 101.14. Moreover, we compared the results considering that M4 and 101.14 were previously described to have lower and higher susceptibility to salt stress, respectively. This study highlighted the greater capability of M4 to maintain and adapt energy metabolism (i.e., synthesis of ATP and NAD(P)H) and to sustain the activation of salt-protective mechanisms (i.e., Na sequestration into the vacuole and synthesis of osmoprotectant compounds). Comparitively, in 101.14 the energy metabolism was deeply affected and there was an evident induction of the enzymatic antioxidant system that occurred, pointing to a metabolic scenario typical of a suffering tissue. Overall, this study describes for the first time in grapevine roots some of the more crucial events that characterize positive (M4) or negative (101.14) responses evoked by salt stress conditions.

scholarly journals Coevolutionary fine-tuning: evidence for genetic tracking between a specialist wasp parasitoid and its aphid host in a dual metapopulation interaction

2011 ◽  
Vol 102 (2) ◽  
pp. 149-155 ◽  
Author(s):  
F.N. Nyabuga ◽  
H.D. Loxdale ◽  
D.G. Heckel ◽  
W.W. Weisser
Keyword(s):  
Population Structure ◽  
Life Histories ◽  
Mantel Test ◽  
Fine Tuning ◽  
Red Queen Hypothesis ◽  
Shared Allele ◽  
Metapopulation Structure ◽  
Population Structures ◽  
Associated Species ◽  
Aphid Host

AbstractIn the interaction between two ecologically-associated species, the population structure of one species may affect the population structure of the other. Here, we examine the population structures of the aphidMetopeurum fuscoviride, a specialist on tansyTanacetum vulgare, and its specialist primary hymenopterous parasitoidLysiphlebus hirticornis, both of which are characterized by multivoltine life histories and a classic metapopulation structure. Samples of the aphid host and the parasitoid were collected from eight sites in and around Jena, Germany, where both insect species co-occur, and then were genotyped using suites of polymorphic microsatellite markers. The host aphid was greatly differentiated in terms of its spatial population genetic patterning, while the parasitoid was, in comparison, only moderately differentiated. There was a positive Mantel test correlation between pairwise shared allele distance (DAS) of the host and parasitoid, i.e. if host subpopulation samples were more similar between two particular sites, so were the parasitoid subpopulation samples. We argue that while the differences in the levels of genetic differentiation are due to the differences in the biology of the species, the correlations between host and parasitoid are indicative of dependence of the parasitoid population structure on that of its aphid host. The parasitoid is genetically tracking behind the aphid host, as can be expected in a classic metapopulation structure where host persistence depends on a delay between host and parasitoid colonization of the patch. The results may also have relevance to the Red Queen hypothesis, whereupon in the ‘arms race’ between parasitoid and its host, the latter ‘attempts’ to evolve away from the former.

PSYCHOLOGICAL FACTORS OF POSITIVE IMAGE DEVELOPMENT OF YOUNG TEACHER OF THE PEDAGOGICAL INSTITUTE

2018 ◽  
pp. 11-13
Author(s):  
S. Baida
Keyword(s):  
Key Words ◽  
Psychological Factors ◽  
Professional Activity ◽  
Successful Development ◽  
Research Results ◽  
Positive Image ◽  
Pedagogical Institute ◽  
Young Teacher ◽  
Internal Side ◽  
Effective Use

The research results of psychological factors which form the positive image of young teacher of pedagogical institutes are highlighted in the article. The image of teachers is interpreted as the purposefully formed, which determines interactive description of external and internal side of personality of teacher that influences on efficiency of his professional activity. Such basic psychological factors of its successful development are distinguished: attractive appearance, effective use of verbal and unverbal means of intercourse, internal accordance of "I'm" character to the selected profession. Key words: psychological factors, development, positive image, young teacher, pedagogical institution.

Sign in / Sign up

Export Citation Format

Share Document