scholarly journals Field evidence of intra- and interspecific predation in rock-pool corixids (Heteroptera, Corixidae)

1992 ◽  
Vol 3 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Irmeli Pajunen ◽  
V. Ilmari Pajunen
Keyword(s):  
High Mortality ◽  
Developmental Stages ◽  
Field Conditions ◽  
Considerable Proportion ◽  
Rock Pool ◽  
Field Evidence ◽  
Large Numbers ◽  
Interspecific Predation

Small corixid larvae were introduced into a rock-pool containing large numbers of later developmental stages. High mortality of small larvae was observed. A considerable proportion of larval carcases recovered each had triangular holes on its upper surface. Similar holes are characteristic of carcases recovered in laboratory cannibalism experiments. The dimensions of the punctures in field and laboratory samples match closely. Predatory interactions between large and small rock-pool corixid larvae are thus common in field conditions.

scholarly journals Evaluation of Effective and Practical Euthanasia Methods for Larval African Clawed Frogs (Xenopus laevis)

2020 ◽  
Vol 59 (3) ◽  
pp. 269-274
Author(s):  
Ilana A Galex ◽  
Cameron M Gallant ◽  
Nicole D'Avignon ◽  
Lauren M Kuchenbrod ◽  
Craig A Fletcher ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Developmental Stages ◽  
Age Group ◽  
Research Model ◽  
Larval Stages ◽  
Large Numbers ◽  
Guidance Documents ◽  
Stock Solutions ◽  
Tricaine Methanesulfonate ◽  
Tank Water

Larval, or tadpole-stage Xenopus laevis frogs are a popular research model for developmental biology and disease studies. Existing euthanasia guidance documents offer recommendations for both eggs and adult stages, yet do not specifically address the larval stage. Data evaluating effective euthanasia methods for groups of X. laevis tadpoles would therefore be useful. The goal of the current study was to evaluate the efficacy of various immersion euthanasia procedures on tadpoles: tricaine methanesulfonate (MS222) at 6 g/L, eugenol at 800 μL/L and rapid chilling (2 to 4 °C). We also evaluated tadpoles at various developmental stages (NF stages 46, 47 and 49). Tadpoles (n = 70) were exposed to euthanasia solution for 15 min, and controls (n = 40) were placed in housing tank water for 15 min. All animals were then placed in recovery tanks containing housing tank water for 4 h to confirm irreversibility of each agent. Cessation of the heartbeat was assessed at the end of euthanasia solution exposure and at each hour thereafter. We found that immersion in a 6 g/L solution of MS222 resulted in 100% euthanasia of all larval stages tested. Conversely, eugenol produced variable euthanasia rates that were affected by both age group and batches of stock solutions. Rapid chilling was completely ineffective as a euthanasia method in our study. Based on our findings, we recommend MS222 as an effective and practical means of euthanizing large numbers of X. laevis tadpoles.

Observations on Scale Production in Pyramimonas Amylifera Conrad

1966 ◽  
Vol 1 (4) ◽  
pp. 429-438
Author(s):  
IRENE MANTON
Keyword(s):  
Developmental Stages ◽  
Basic Problem ◽  
Scale Production ◽  
Body Type ◽  
Primary Object ◽  
Large Numbers ◽  
Golgi Structure ◽  
Flagellar Scales ◽  
Duct Opening ◽  
Narrow Duct

Scale production has been studied after glutaraldehyde fixation with the primary object of tracing the source of flagellar scales which this species is known to possess (Manton, Oates & Parke, 1963). Large numbers of all types of flagellar scales, unmixed with body-type scales, are detectable at all times, stored in an orderly arrangement within a vesicular scale reservoir of characteristic morphology which is described. These scales are liberated through a narrow duct opening to the cell exterior near the flagellar bases. This duct is thought to be temporary and subject to reformation with minor change of site, since open ducts are more frequently encountered in darkness than by day; some putative developmental stages are illustrated. Observations on other details of scale production include demonstration of the formation of all types of body scales within the Golgi cisternae, sometimes together with a few flagella-type scales. The larger body-type scales are uniformly oriented within the Golgi cisternae in relation to the position of the subtending endoplasmic reticulum. This orientation is lost before liberation to the cell surface, which occurs from moderate-sized detached vesicles in an unknown manner. The implications of these findings for an understanding of Golgi structure and of the basic problem of scale arrangement on the receiving sites are discussed in a preliminary way.

Observations on the gregarine Rotundula gammari (Diesing, 1859), Goodrich, 1949

Parasitology ◽  
1964 ◽  
Vol 54 (1) ◽  
pp. 195-199 ◽  
Author(s):  
C. C. Narasimhamurti
Keyword(s):  
Developmental Stage ◽  
Royal Society ◽  
Developmental Stages ◽  
Local Population ◽  
Gammarus Pulex ◽  
Taxonomic Relationship ◽  
Large Numbers ◽  
The Many ◽  
Relationship Of ◽  
Infected Material

1. A local population of Gammarus pulex, infected with Heliospora longissima and Rotundula gammari, was found to have an intracellular developmental stage.2. Experimental infections of G. pulex were made with the two species of gregarines. In the case of R. gammari infections, large numbers of intracellular developmental stages were found.3. The taxonomic relationship of the genera Cephaloidophora and Rotundula is discussed.Thanks are due to Dr P. Tate for constant encouragement and guidance during the course of this work and for the many helpful suggestions in the preparation of the manuscript. Thanks are also due to Mr D. W. T. Crompton for kindly giving me the infected material. The work was completed during the tenure of a Royal Society and Nuffield Foundation Commonwealth Bursary.

Some characteristics of the germination of Queensland blue grass on cracking black earths

1978 ◽  
Vol 29 (6) ◽  
pp. 1147 ◽  
Author(s):  
LA Watt
Keyword(s):  
Water Availability ◽  
Field Conditions ◽  
Adaptive Mechanism ◽  
Surface Layers ◽  
Large Numbers ◽  
Actual Field ◽  
Germinated Seeds

An intermediate stationary stage in the germination of Queensland blue grass (Dicanthium sericeum L.) caused by limiting water availability was examined. It was found that partially germinated seed can maintain viability over extended periods of desiccation and that large numbers of these partially germinated seeds are found under simulated and actual field conditions. Results indicate that this phenomenon is an adaptive mechanism which assists establishment on black cracking earths in which rapid drying of surface layers is characteristic.

scholarly journals Characterizing rhizosphere microbiota of peanut (Arachis hypogaea L.) from pre-sowing to post-harvest of crop under field conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ankit T. Hinsu ◽  
Ketankumar J. Panchal ◽  
Ramesh J. Pandit ◽  
Prakash G. Koringa ◽  
Ramesh K. Kothari
Keyword(s):  
Developmental Stages ◽  
Hot Spot ◽  
Soil Samples ◽  
Field Conditions ◽  
Bulk Soil ◽  
Design Stage ◽  
Post Harvest ◽  
Arachis Hypogaea L ◽  
Crop Development ◽  
Plant Growth Promoting

AbstractThe rhizosphere, a narrow zone of soil near plant roots, is a hot spot for microbial activity. Rhizosphere microbiota directly or indirectly benefit plants by supplementing nutrients, producing beneficial chemicals, or suppressing pathogens. Plants attract and modulate bacteria within the rhizosphere by releasing exudates. Plants also tend to select the rhizosphere microbiota based on their needs; a phenomenon termed as “rhizosphere effect”. In this study, we characterized the rhizosphere microbiota of peanut plants across the crop development cycle from pre-sowing of seeds to post-harvest of crop under field conditions. The rhizosphere and bulk soil samples from different crop developmental stages were also compared. The composition of bulk soil microbiota resembled microbiota of pre-sowing and post-harvest soil and was markedly different from rhizosphere soil samples. Rhizosphere samples were enriched with multiple organisms mostly from the Proteobacteria, Firmicutes and Bacteroidota phyla. Differences in diversity were observed among the rhizosphere samples but not in bulk soil across different crop development stages. Pseudomonas_M indica was highly enriched during the germination of seeds. Furthermore, Plant Growth Promoting (PGP) bacteria like Bacillus were enriched during the middle stages of crop development but there was a decline in PGP organisms in the matured crop stage. We also observed a significant association of pH and Electrical Conductivity (EC) with the profiles of microbial community. Overall, this study portrayed the changes in rhizosphere microbiota of peanut during different developmental stages of crop and may help to design stage specific bio-strategies such as bio-fertilizer to improve crop yield.

LABORATORY STUDIES ON THE TOXICITY OF INSECTICIDES TO THE BERTHA ARMYWORM (MAMESTRA CONFIGURATA) (LEPIDOPTERA: NOCTUIDAE)

1975 ◽  
Vol 107 (8) ◽  
pp. 865-872 ◽  
Author(s):  
C. R. Harris ◽  
S.A. Turnbull
Keyword(s):  
Direct Contact ◽  
Developmental Stages ◽  
Contact Toxicity ◽  
Mamestra Configurata ◽  
Larval Stages ◽  
Large Numbers ◽  
Third Stage ◽  
History Of ◽  
Dual Objectives ◽  
Bertha Armyworm

AbstractThis study had dual objectives: to select a series of insecticides toxic to the bertha armyworm, Mamestra configurata (Walk.), and to determine susceptibility of the various developmental stages to insecticides. Pupae were collected from infested rapeseed fields in Alberta and a laboratory rearing procedure suitable for production of large numbers of insects was devised. The direct contact toxicity of 50 insecticides to third-stage larvae was assessed. Methomyl and DDT were included as standard insecticides. None of the experimental insecticides was as toxic as methomyl but about one half were more toxic than DDT. Tests with representative organochlorine, organophosphorus, and carbamate insecticides indicated that all caused rapid knockdown of third-stage larvae. There was no evidence of subsequent recovery. After the life history of the bertha armyworm under controlled environmental conditions was determined, tests were conducted to ascertain the susceptibility of the various developmental stages to methomyl, chlorpyrifos, leptophos, and methidathion. Eggs and first and second stage larvae were more susceptible to direct contact applications of the insecticides than were the later larval stages, pupae, and adults.

Gulls and Aircraft

1978 ◽  
Vol 5 (4) ◽  
pp. 277-280 ◽  
Author(s):  
Victor E. F. Solman
Keyword(s):  
Fast Moving ◽  
Insect Population ◽  
Considerable Proportion ◽  
Food Wastes ◽  
Jet Engines ◽  
Mouse Population ◽  
Early Autumn ◽  
Large Numbers

Birds, struck during flight by fast-moving modern aircraft or getting ingested in jet engines, cause numerous serious accidents of which some involve human deaths. Gulls of various species are the birds involved in a considerable proportion of these accidents due to bird-strikes.Gull-strikes of aircraft in flight may be expected:1. When there is a chronic attraction such as a concentrated worm or insect population, a high mouse population, or some other biological attractant;2. When there is lack of care in disposal of food-wastes;3. When drainage on an airfield or on flat-roofed buildings is not properly designed or is not functioning well; or4. During the early autumn when large numbers of inexperienced, immature gulls are in flight.

scholarly journals MORTALITY CAUSED BY ARMILLARIA ROOT ROT, PERIDERMIUM RUSTS AND OTHER DESTRUCTIVE AGENTS IN LODGEPOLE PINE REGENERATION

1964 ◽  
Vol 40 (3) ◽  
pp. 350-361 ◽  
Author(s):  
J. A. Baranyay ◽  
G. R. Stevenson
Keyword(s):  
Mortality Rate ◽  
High Mortality ◽  
Root Rot ◽  
Lodgepole Pine ◽  
Armillaria Mellea ◽  
Large Numbers ◽  
Armillaria Root Rot ◽  
Pine Regeneration

Surveys of diseases and other forms of damage in naturally regenerated lodgepole pine were carried out in 1959 and 1962 near Robb, Alberta in an area that had been burned in May, 1941. Eighteen and one-half per cent of the trees on seven 0.05-acre plots were dead in 1959. The additional mortality on the same plots from 1959 to 1962 was 27.7 per cent. The seemingly high mortality was not considered excessive, in light of the large numbers of trees remaining on the plots, but further examinations will show if the present high mortality rate is sustained. The most important destructive agent up to 1962 was Armillaria mellea (Vahl ex Fr.) Quél. The most important non-infectious destructive agents were game and rodents.

scholarly journals Some Mixotrophic Flagellate Species Selectively Graze on Archaea

2016 ◽  
Vol 83 (2) ◽  
Author(s):  
Miguel Ballen-Segura ◽  
Marisol Felip ◽  
Jordi Catalan
Keyword(s):  
Food Webs ◽  
Prey Selection ◽  
Field Conditions ◽  
Mountain Lake ◽  
High Mountain ◽  
Selective Feeding ◽  
New Paradigm ◽  
Content Type ◽  
High Mountain Lake ◽  
Field Evidence

ABSTRACT Many phototrophic flagellates ingest prokaryotes. This mixotrophic trait becomes a critical aspect of the microbial loop in planktonic food webs because of the typical high abundance of these flagellates. Our knowledge of their selective feeding upon different groups of prokaryotes, particularly under field conditions, is still quite limited. In this study, we investigated the feeding behavior of three species (Rhodomonas sp., Cryptomonas ovata, and Dinobryon cylindricum) via their food vacuole content in field populations of a high mountain lake. We used the catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) protocol with probes specific for the domain Archaea and three groups of Eubacteria: Betaproteobacteria, Actinobacteria, and Cytophaga-Flavobacteria of Bacteroidetes. Our results provide field evidence that contrasting selective feeding exists between coexisting mixotrophic flagellates under the same environmental conditions and that some prokaryotic groups may be preferentially impacted by phagotrophic pressure in aquatic microbial food webs. In our study, Archaea were the preferred prey, chiefly in the case of Rhodomonas sp., which rarely fed on any other prokaryotic group. In general, prey selection did not relate to prey size among the grazed groups. However, Actinobacteria, which were clearly avoided, mostly showed a size of <0.5 μm, markedly smaller than cells from the other groups. IMPORTANCE That mixotrophic flagellates are not randomly feeding in the main prokaryotic groups under field conditions is a pioneer finding in species-specific behavior that paves the way for future studies according to this new paradigm. The particular case that Archaea were preferentially affected in the situation studied shows that phagotrophic pressure cannot be disregarded when considering the distribution of this group in freshwater oligotrophic systems.

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