scholarly journals Effect of a dragonfly (<i>Bradinopyga strachani</i> Kirby, 1900) on the density of mosquito larvae in a field experiment using mesocosms

Web Ecology ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Daniel Acquah-Lamptey ◽  
Roland Brandl
Keyword(s):  
Field Experiment ◽  
Laboratory Experiments ◽  
Water Bodies ◽  
Mosquito Population ◽  
Mosquito Larvae ◽  
Promising Strategy

Abstract. Laboratory experiments with food-deprived larvae of odonates suggested that these predators may have the potential to control mosquito populations. However, it remains unclear whether larvae of odonates co-occur with mosquito larvae in the field and whether larvae of odonates reduce the density of mosquito larvae in the field. We exposed 35 water-filled concrete containers in the field in shady and sunny conditions. Some of these containers were partially covered (for simplicity called closed containers, allowing only mosquitoes to lay eggs), whereas others remained open. The density of mosquito larvae was higher in shaded containers and in closed containers. The multivoltine odonate Bradinopyga strachani colonized open containers and the occurrence of these predators resulted in a clear reduction of the mosquito population. Our results indicate that increasing the colonization of water bodies by Bradinopyga strachani is a promising strategy for controlling populations of mosquitoes.

scholarly journals Inhibition or Facilitation? Contrasted Inter-Specific Interactions in Sphagnum under Laboratory and Field Conditions

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1554
Author(s):  
Chao Liu ◽  
Zhao-Jun Bu ◽  
Azim Mallik ◽  
Yong-Da Chen ◽  
Xue-Feng Hu ◽  
...  
Keyword(s):  
Field Experiment ◽  
Species Interactions ◽  
Laboratory Experiments ◽  
Resource Competition ◽  
Specific Interactions ◽  
Interaction Type ◽  
Negative Effects ◽  
Experiment Data ◽  
The Stability ◽  
Positive Effect

In a natural environment, plants usually interact with their neighbors predominantly through resource competition, allelopathy, and facilitation. The occurrence of the positive effect of allelopathy between peat mosses (Sphagnum L.) is rare, but it has been observed in a field experiment. It is unclear whether the stability of the water table level in peat induces positive vs. negative effects of allelopathy and how that is related to phenolic allelochemical production in Sphagnum. Based on field experiment data, we established a laboratory experiment with three neighborhood treatments to measure inter-specific interactions between Sphagnum angustifolium (Russ.) C. Jens and Sphagnum magellanicum Brid. We found that the two species were strongly suppressed by the allelopathic effects of each other. S. magellanicum allelopathically facilitated S. angustifolium in the field but inhibited it in the laboratory, and relative allelopathy intensity appeared to be positively related to the content of released phenolics. We conclude that the interaction type and intensity between plants are dependent on environmental conditions. The concentration of phenolics alone may not explain the type and relative intensity of allelopathy. Carefully designed combined field and laboratory experiments are necessary to reveal the mechanism of species interactions in natural communities.

scholarly journals LARVICIDAL ACTIVITY OFTITHONIA DIVERSIFOLIALEAF EXTRACT ONPERI-URBAN MOSQUITO LARVEA INABAKALIKI; ALTERNATIVE TO INSECTICIDE DEVELOPMENT.

2015 ◽  
Vol 7 (1) ◽  
pp. 1225-1228
Author(s):  
UHUO CA ◽  
OKEREKE CN ◽  
NWELE ED ◽  
OGBONNA S.U ◽  
NWANCHOR K.C ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Adverse Effects ◽  
Bioactive Compounds ◽  
Larvicidal Activity ◽  
Urban Areas ◽  
Insect Pests ◽  
Anopheles Mosquito ◽  
Mosquito Population ◽  
Mosquito Larvae ◽  
Dose Dependent

The bioassay activitiesofTithonia diversifolia leave extract was conducted on the larvae of Anopheles mosquito collected at peri-urban areas of Abakaliki Ebonyi State, using the concentrations of the extract in dilutions at 50/100ml, 40/100ml, 30/100ml and 20/100ml introduced with 10 Anopheles mosquito larvae each in four replicates and allowed for 3hrs. Mean mortality rate of the larvae were observed after the first hour, thus 30%, 10%, 05% and 0% respectively while in the 2nd hour were 60%, 40%, 20% and 10% and in the 3rd hour were 80%, 60%, 50% & 30% respectively. The result thus revealed that the treatment is dose dependent and that the studied specie has some bioactive compounds that can be exploited for insect pests control hence observed to be sensitive in anopheles mosquito larvae. Therefore Tithonia diversifolialeaf extract could be used as a bioassay for the control of mosquito due to its active properties as this has exhibited adverse effects on the larvae thereby reducing the mosquito population and thus reducing the malarious infection associated with the bite of mosquito.

ESTIMATION OF NITROGLYCERINE WATER SOLUTION TOXICITY BY HISTOLOGICAL AND CYTOLOGICAL INDICES USING DANIO RERIO AS A CASE STUDY

Fisheries ◽  
2020 ◽  
Vol 2020 (1) ◽  
pp. 66-70
Author(s):  
Yuri Simakov ◽  
Dmitry Nikiforov-Nikishin ◽  
Larisa Bychkova ◽  
Nadegda Lyubovskaya
Keyword(s):  
Danio Rerio ◽  
Laboratory Experiments ◽  
Maximum Permissible Concentration ◽  
Water Solution ◽  
Water Bodies ◽  
Hematological Indices ◽  
First Time ◽  
Pharmaceutical Enterprises

The results of laboratory experiments on nitroglycerine toxicity detected by histological and cytological indices are presented, using Danio rerio as a case study. For the first time, there are shown the changes in liver and kidneys, both at tissular and cellular levels, induced by administered concentrations of nitroglycerine. The results obtained appear to be important for water bodies’ preservation and elaboration of MPC standards. The intake of nitroglycerine into water bodies is due, mainly, to discharge from pharmaceutical enterprises, demolition works, and outflow from explosives storehouses. Fish turned out to be sensitive to nitroglycerine as indicated by histological and hematological indices. Maximum permissible concentration, MPC, for Danio rerio is determined to be equal to 0.5 mg/l.

The chemical composition of the soil in a factorial experiment with citrus. I. Exchangeable metal cations and their effect on the cation content of citrus

1960 ◽  
Vol 11 (2) ◽  
pp. 208 ◽  
Author(s):  
H Groenewegen ◽  
D Bouma
Keyword(s):  
Field Experiment ◽  
Cover Crops ◽  
Laboratory Experiments ◽  
Appreciable Effect ◽  
Exchangeable Calcium ◽  
Cation Content ◽  
Two Factors ◽  
Exchangeable Magnesium ◽  
Citrus Leaves ◽  
Exchangeable Form

In a factorial field experiment with citrus it was found that application of ammonium sulphate caused a greater proportionate reduction in the exchangeable calcium of the soil than in the exchangeable potassium. Short-term laboratory experiments with virgin soil, to which ammonium was added, suggested that at least two factors were involved. If solutions of high electrolyte concentrations were added, a greater release of exchangeable calcium than of potassium occurred, relative to the amounts of these ions originally present in exchangeable form. Secondly, a release of potassium from non-exchangeable to exchangeable form also occurred. In the 0–4 in. layer of the field experiment, exchangeable magnesium was reduced in the same proportion as exchangeable calcium. In the 4–12 in. layer, exchangeable magnesium was reduced relatively more than calcium. The same trend was apparent in laboratory experiments. In one experiment, for example, the original amount of magnesium was reduced by 76 per cent., and calcium by 66 per cent. A comparison between cultural treatments showed that the potassium content of the soil from a bare surface treatment was much lower than that from treatments with cover crops. The changes in soil composition had no appreciable effect on the cation content of citrus leaves, and some reasons for this are discussed.

scholarly journals Announcements of Support and Public Good Provision

2017 ◽  
Vol 107 (12) ◽  
pp. 3760-3787 ◽  
Author(s):  
Judd B. Kessler
Keyword(s):  
Public Goods ◽  
Field Experiment ◽  
Prosocial Behavior ◽  
Public Good ◽  
Large Scale ◽  
Laboratory Experiments ◽  
Public Good Provision ◽  
Scale Field ◽  
Large Scale Field ◽  
Good Provision

Providing information about contributions to public goods is known to generate further contributions. However, it is often impossible to provide verifiable information on contributions. Through a large-scale field experiment and a series of laboratory experiments, I show that nonbinding announcements of support for a public good encourage others to contribute, even when actual contributions might not or cannot be made. Providing a way to easily announce support for a charity increases donations by $865 per workplace fundraising campaign (or 16 percent of average giving). I discuss implications for understanding prosocial behavior and for organizations aiming to increase contributions to public goods. (JEL C93, D64, D83, H41, L31)

Nitrous oxide production from granular nitrogen fertilizers applied to a silt loam soil

2003 ◽  
Vol 83 (5) ◽  
pp. 521-532 ◽  
Author(s):  
M. Tenuta and E. G. Beauchamp
Keyword(s):  
Nitrous Oxide ◽  
Field Experiment ◽  
Laboratory Experiment ◽  
Laboratory Experiments ◽  
N Fertilizer ◽  
Nitrogen Fertilizers ◽  
Silt Loam ◽  
N Fertilizers ◽  
Oxide Production ◽  
Nitrous Oxide Production

One field and two laboratory experiments were conducted to determine the relative magnitude and pattern of N2O production from several granular N fertilizers including urea, ammonium nitrate, calcium nitrate, ammonium sulfate and, in a laboratory experiment, monoammonium and diammonium phosphates. Several parameters, in particular soil water content, were studied for their roles in N2O production with these fertilizers. The field experiment was conducted at the Elora Research Station (20 km north of Guelph) on Conestoga silt loam during July on a site previously cropped to barley. Three methods were employed to assess N2O production following N fertilizer treatments in the field experiment, viz., soil cover, soil core and profile distribution. The data with each method revealed that incorporated urea produced the greatest quantity of N2O especially in the first few days following application. Shortly after urea application and incorporation (10 cm), N2O was detected at a depth of 50 cm indicating gas produced in the tilled layer was transported to lower depths. Data obtained with the intact core method showed that nitrification preceeded denitrification as the source of N2O produced during a wetting event as air-filled porosity decreased from 65% to less than 50%, respectively. The laboratory experiments showed that under aerobic conditions N2O production was generally greater with urea than the other N fertilizers. The greater production of N2O with urea was associated with N2O-accumulation. In the second laboratory experiment, saturating the soil following 14 d of aerobic incubation showed enhanced N2O production with ammonium phosphate fertilizers. Our findings indicate refinement of methods to predict N2O emissions based on N fertilizer source use and moisture can reduce uncertainties in national estimates of N2O emissions from agricultural soils. Key words: Nitrous oxide production, nitrogen fertilizers, soil atmosphere profiles, nitrification, denitrification, air-filled porosity

Triple isotope effects accompanying evaporation of water: new insights from laboratory experiments

2020 ◽  
Author(s):  
Anna Pierchala ◽  
Kazimierz Rozanski ◽  
Marek Dulinski ◽  
Zbigniew Gorczyca ◽  
Robert Czub
Keyword(s):  
Surface Water ◽  
Liquid Phase ◽  
Laboratory Experiments ◽  
Isotope Effects ◽  
Water Bodies ◽  
Fractionation Factor ◽  
Preparation Methods ◽  
Mass Spectrom ◽  
Health Studies ◽  
Surface Water Bodies

&lt;p&gt;Stable isotopes of hydrogen and oxygen (&lt;sup&gt;2&lt;/sup&gt;H and &lt;sup&gt;18&lt;/sup&gt;O) are often used for quantification of water budgets of lakes and other surface water bodies, in particular for the assessment of underground components of those budgets [1]. Recent advances in laser spectroscopy enabled simultaneous analyses of &lt;sup&gt;2&lt;/sup&gt;H, &lt;sup&gt;18&lt;/sup&gt;O and &lt;sup&gt;17&lt;/sup&gt;O content in water, with measurement uncertainties comparable (&amp;#948;&lt;sup&gt;18&lt;/sup&gt;O) or surpassing (&amp;#948;&lt;sup&gt;2&lt;/sup&gt;H) those routinely achieved by off-line sample preparation methods combined with conventional IRMS technique [2]. This open up the doors for improving reliability of isotope-aided budgets of surface water bodies by adding third isotope tracer (&lt;sup&gt;17&lt;/sup&gt;O). This, however, requires adequate information on triple isotope effects accompanying evaporation of water, in particular the kinetic isotope effect related to evaporation of &lt;sup&gt;1&lt;/sup&gt;H&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;17&lt;/sup&gt;O isotopologue.&lt;/p&gt;&lt;p&gt;Here we present the results of dedicated laboratory experiments aimed at quantification of triple isotope effects accompanying evaporation of water under fully developed diffusive sublayer [3]. Identical containers with predefined mass of water of known isotopic composition were placed in an isolated chamber with controlled atmosphere during the experiment (temperature, relative humidity). The chamber was flushed with synthetic air. At regular time intervals (approximately one week) containers were removed one by one from the chamber, the remaining mass of water in the removed container was determined gravimetrically, and stored for subsequent isotope analyses. The flow rate was adjusted at each step of the process to keep humidity inside the chamber constant. Evaporation continued until approximately half of the initial mass of water was removed from the containers. The experiment was repeated under diiferent conditions inside the chamber (two different temperatures and three different values of relative humidty).&lt;/p&gt;&lt;p&gt;The results of the experiments were interpreted in the framework of Craig-Gordon model of evaporation [3]. It turned out that the assumption often used in the description of isotopic effects accompanying evaporation that liquid phase is isotopically homogeneous during the process, leads to conflicting results for three isotope systems in use. However, if surface enrichment of the liquid phase, different for each heavy isotopologue (&lt;sup&gt;1&lt;/sup&gt;H&lt;sup&gt;2&lt;/sup&gt;H&lt;sup&gt;16&lt;/sup&gt;O, &lt;sup&gt;1&lt;/sup&gt;H&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;18&lt;/sup&gt;O, &lt;sup&gt;1&lt;/sup&gt;H&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;17&lt;/sup&gt;O) is included in the model, consistent results for all three isotopes can be achieved, with calculated kinetic fractionation factor for &lt;sup&gt;1&lt;/sup&gt;H&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;17&lt;/sup&gt;O isotopologue equal 14.76 &amp;#177; 0.48 &amp;#8240;,. This value agrees, within the quoted uncertainty, with the value of 14.60 &amp;#177; 0.30 &amp;#8240; obtained by Barkan and Luz [4].&amp;#160;&amp;#160;&lt;/p&gt;&lt;p&gt;Acknowledgements: The presented work was supported by National Science Centre (research grant No. 2016/23/B/ST10/00909) and by the Ministry of Science and Higher Education (project no. 16.16.220.842 B02)&lt;/p&gt;&lt;p&gt;References:&lt;br&gt;[1] &amp;#160; Rozanski K. Froehlich K. Mook WG. Technical Documents in Hydrology, No. 39, Vol. III, UNESCO, Paris, 2001 117 pp.&lt;br&gt;[2]&amp;#160;&amp;#160; Pierchala A, Rozanski K, Dulinski M, Gorczyca Z, Marzec M, Czub R, Isotopes in Environmental and Health Studies, 2019 (55) 290-307.&lt;br&gt;[3]&amp;#160;&amp;#160; Horita, J. Rozanski K. Cohen S. 2007. Isotopes in Environmental and Health Studies, 2007 (44) 23-49.&lt;br&gt;[4]&amp;#160;&amp;#160; Barkan E. Luz B. Rapid Commun. Mass Spectrom., 2007(21) 2999-3005.&lt;/p&gt;

scholarly journals Potential negative impacts and low effectiveness in the use of African annual killifish in the biocontrol of aquatic mosquito larvae in temporary water bodies

2010 ◽  
Vol 3 (1) ◽  
pp. 89 ◽  
Author(s):  
Martin Reichard ◽  
Brian R Watters ◽  
Rudolf H Wildekamp ◽  
Rainer Sonnenberg ◽  
Béla Nagy ◽  
...  
Keyword(s):  
Water Bodies ◽  
Mosquito Larvae ◽  
Annual Killifish ◽  
Temporary Water Bodies ◽  
Temporary Water ◽  
Negative Impacts

scholarly journals Automatic detection of surface-water bodies from Sentinel-1 images for effective mosquito larvae control

2021 ◽  
Vol 15 (01) ◽  
Author(s):  
Georgios Ovakoglou ◽  
Ines Cherif ◽  
Thomas K. Alexandridis ◽  
Xanthoula-Eirini Pantazi ◽  
Afroditi-Alexandra Tamouridou ◽  
...  
Keyword(s):  
Surface Water ◽  
Automatic Detection ◽  
Water Bodies ◽  
Mosquito Larvae ◽  
Surface Water Bodies

scholarly journals Optimal background matching camouflage

2017 ◽  
Vol 284 (1858) ◽  
pp. 20170709 ◽  
Author(s):  
Constantine Michalis ◽  
Nicholas E. Scott-Samuel ◽  
David P. Gibson ◽  
Innes C. Cuthill
Keyword(s):  
Field Experiment ◽  
Laboratory Experiments ◽  
Bird Predation ◽  
Computer Screen ◽  
Low Level ◽  
Background Matching ◽  
Analogous Data ◽  
Statistical Sense ◽  
Predator Learning ◽  
Homogeneous Environment

Background matching is the most familiar and widespread camouflage strategy: avoiding detection by having a similar colour and pattern to the background. Optimizing background matching is straightforward in a homogeneous environment, or when the habitat has very distinct sub-types and there is divergent selection leading to polymorphism. However, most backgrounds have continuous variation in colour and texture, so what is the best solution? Not all samples of the background are likely to be equally inconspicuous, and laboratory experiments on birds and humans support this view. Theory suggests that the most probable background sample (in the statistical sense), at the size of the prey, would, on average, be the most cryptic. We present an analysis, based on realistic assumptions about low-level vision, that estimates the distribution of background colours and visual textures, and predicts the best camouflage. We present data from a field experiment that tests and supports our predictions, using artificial moth-like targets under bird predation. Additionally, we present analogous data for humans, under tightly controlled viewing conditions, searching for targets on a computer screen. These data show that, in the absence of predator learning, the best single camouflage pattern for heterogeneous backgrounds is the most probable sample.

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