scholarly journals Conspecifics, not plant reproductive tissues, reduce omnivore prey consumption

2019 ◽  
Author(s):  
S. Rinehart ◽  
J.D. Long
Keyword(s):  
Population Level ◽  
Field Studies ◽  
Predation Rate ◽  
Scale Insect ◽  
Prey Consumption ◽  
Intraspecific Interactions ◽  
Conspecific Density ◽  
Reproductive Tissues ◽  
Consumption Rates ◽  
Per Capita

AbstractPlant reproductive tissues (PRTs) can decrease (via reduced consumption) or increase (via numerical response) an omnivores consumption of animal prey. Although PRTs can increase predation pressure through numerical responses of omnivores, PRTs may also suppress predation by increasing omnivore interactions with conspecifics. Despite this potential, studies of the impacts of PRTs on predation by omnivores often overlook the effect of these tissues on intraspecific interactions between omnivores. We designed three studies to examine how PRTs and conspecific density impact prey consumption by ladybeetle omnivores. First, we assessed how PRTs impact scale insect consumption by isolated ladybeetles. Second, we measured how PRTs influence ladybeetle prey suppression when numerical responses were possible. Third, because initial experiments suggested the consumption rates of individual ladybeetles depended upon conspecific density, we compared per capita consumption rates of ladybeetles across ladybeetle density. PRTs did not influence prey consumption by isolated ladybeetles. When numerical responses were possible, PRTs did not influence total predation on prey despite increasing ladybeetle density, suggesting that PRTs decreased per capita prey consumption by ladybeetles. The discrepancy between our lab and field studies is likely a consequence of differences in ladybeetle density - the presence of only two other conspecifics decreased per capita prey consumption by 76%. Our findings suggest that PRTs may not alter the population level effects of omnivores on prey when omnivore numerical responses are offset by reductions in per capita predation rate.

Prey consumption rates and compatibility with pesticides of four predatory mites from the family Phytoseiidae attacking Thrips palmi Karny (Thysanoptera: Thripidae)

2012 ◽  
Vol 68 (9) ◽  
pp. 1289-1295 ◽  
Author(s):  
Andrew GS Cuthbertson ◽  
James J Mathers ◽  
Pat Croft ◽  
Nicola Nattriss ◽  
Lisa F Blackburn ◽  
...  
Keyword(s):  
Predatory Mites ◽  
Prey Consumption ◽  
Thrips Palmi ◽  
The Family ◽  
Consumption Rates

Hygienic assessment of potential ecotoxicological risk of the use of new insecticide spiromesifen in agriculture of Ukraine

2021 ◽  
pp. 62-67
Author(s):  
I.V. Tkachenko ◽  
Keyword(s):  
Chemical Properties ◽  
Terrestrial Ecosystems ◽  
Field Studies ◽  
Climatic Conditions ◽  
Climatic Zones ◽  
Ecotoxicological Risk ◽  
Environmental Objects ◽  
Physico Chemical ◽  
Consumption Rates ◽  
Agricultural Use

Objective: The aim of our work was to study the potential ecotoxicological hazard of a new chemical from the class of tetramic and tetronic acid derivatives - the insecticide spiromesifen, taking into account its physico-chemical properties and impact on the environmental objects. Materials and methods: An assessment of the potential danger of spiromesifen use for ecosystems was carried out on the basis of the calculation of the ecotoxicological hazard (ecotox) by N.N. Melnikov’s method. The field studies were carried out in different agro-climatic zones of Ukraine. The treatment of vineyards and apple trees was carried out at the maximum consumption rates of spiromesifen. Results: According to the literary data and our research, it was found that in the soil-and-climatic conditions of Ukraine, the ecotoxicological risk, when using the new insecticide spiromesifen, is 10,000 times and 7,000 times low than the analogous characteristics of DDT. Ecotox abamectin is 154 times low than ecotox DDT. This makes preparations, based on these substances, more promising and competitive among other pesticides in agricultural use. We can conclude that spiromesifen does not pose a threat to terrestrial ecosystems and health of the population.

scholarly journals Fighting and mating success in giant Australian cuttlefish is influenced by behavioural lateralization

2019 ◽  
Vol 286 (1898) ◽  
pp. 20182507 ◽  
Author(s):  
Alexandra K. Schnell ◽  
Christelle Jozet-Alves ◽  
Karina C. Hall ◽  
Léa Radday ◽  
Roger T. Hanlon
Keyword(s):  
Mating Success ◽  
Population Level ◽  
Theory Model ◽  
Fundamental Question ◽  
Competitive Interactions ◽  
Intraspecific Interactions ◽  
Stable Strategy ◽  
Evolutionary Consequence ◽  
Fitness Advantage ◽  
Fitness Consequences

Behavioural lateralization is widespread. Yet, a fundamental question remains, how can lateralization be evolutionary stable when individuals lateralized in one direction often significantly outnumber individuals lateralized in the opposite direction? A recently developed game theory model predicts that fitness consequences which occur during intraspecific interactions may be driving population-level lateralization as an evolutionary stable strategy. This model predicts that: (i) minority-type individuals exist because they are more likely to adopt unpredictable fighting behaviours during competitive interactions (e.g. fighting); and (ii) majority-type individuals exist because there is a fitness advantage in having their biases synchronized with other conspecifics during interactions that require coordination (e.g. mating). We tested these predictions by investigating biases in giant Australian cuttlefish during fighting and mating interactions. During fighting, most male cuttlefish favoured the left eye and these males showed higher contest escalation; but minority-type individuals with a right-eye bias achieved higher fighting success. During mating interactions, most male cuttlefish favoured the left eye to inspect females. Furthermore, most male cuttlefish approached the female's right side during a mating attempt and these males achieved higher mating success. Our data support the hypothesis that population-level biases are an evolutionary consequence of the fitness advantages involved in intraspecific interactions.

Aggressive interactions affect foraging and use of space in a drift foraging salmonid, Salvelinus malma (Salmoniformes: Salmonidae)

2019 ◽  
Vol 187 (3) ◽  
pp. 774-781 ◽  
Author(s):  
Jeffrey L Cullen ◽  
Gary D Grossman
Keyword(s):  
Foraging Behaviour ◽  
Field Studies ◽  
Habitat Choice ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Intraspecific Interactions ◽  
Use Of Space ◽  
Aggressive Interactions ◽  
Dolly Varden Char ◽  
Alaskan Stream

Abstract Although intraspecific interactions likely affect habitat choice and foraging behaviour in animals, our knowledge regarding how these factors interact is frequently limited to either lab or field studies, but not both. We observed pairs of dominant and subordinate drift-foraging Dolly Varden char (Salvelinus malma) in an Alaskan stream, and quantified intraspecific interactions and foraging behaviour. Dominant individuals had higher foraging rates, occupied slower holding velocities and were displaced shorter distances during bouts compared to subordinate individuals. Individuals initiated bouts more frequently from the downstream position, than from lateral or upstream positions. Dominant individuals were more likely to occupy the upstream position after a bout than subordinates, which ensures that dominants have the first opportunity to capture drifting prey.

scholarly journals Design and analysis of small-scale transmission experiments with animals

2006 ◽  
Vol 135 (2) ◽  
pp. 202-217 ◽  
Author(s):  
A. G. J. VELTHUIS ◽  
A. BOUMA ◽  
W. E. A. KATSMA ◽  
G. NODELIJK ◽  
M. C. M. DE JONG
Keyword(s):  
Infectious Diseases ◽  
Population Level ◽  
Field Studies ◽  
Control Measures ◽  
Experimental Designs ◽  
Small Scale ◽  
Controlled Environment ◽  
Single Factor ◽  
Final Size ◽  
Transmission Data

Interactions between pathogens and hosts at the population level should be considered when studying the effectiveness of control measures for infectious diseases. The advantage of doing transmission experiments compared to field studies is that they offer a controlled environment in which the effect of a single factor can be investigated, while variation due to other factors is minimized. This paper gives an overview of the biological and mathematical aspects, bottlenecks and solutions of developing and executing transmission experiments with animals. Different methods of analysis and different experimental designs are discussed. Final size methods are often used for analysing transmission data, but have never been published in a refereed journal; therefore, they will be described in detail in this paper. We hope that this information is helpful for scientists who are considering performing transmission experiments.

Ethnic and Racial Employment Discrimination in Low-Wage and High-Wage Markets: Randomized Controlled Trials Using Correspondence Tests in Israel

2015 ◽  
Vol 9 (1) ◽  
pp. 113-139 ◽  
Author(s):  
Barak Ariel ◽  
Ilanit Tobby-Alimi ◽  
Irit Cohen ◽  
Mazal Ben Ezra ◽  
Yafa Cohen ◽  
...  
Keyword(s):  
Community Dynamics ◽  
Employment Discrimination ◽  
Geographic Location ◽  
Population Level ◽  
Field Studies ◽  
Law Firms ◽  
High Wage ◽  
Ashkenazi Jews ◽  
Job Interviews ◽  
Wage Earners

Abstract A rich body of literature on employment discrimination exists. Theoretically, discriminatory practices are explained by taste-based discrimination, differences in the bargaining ability of applicants or statistical discrimination. Global experimental research tends to show significant anti-minority attitudes in the hiring process, specifically at the entry stage into the engagement cycle – when an application and resume are sent to the prospective employer. These field studies often employ “correspondence tests,” in which identical, fictitious resumes are sent to employers with differences only in the racial, gender, religious or national origin of the applicant (e.g., the name of the applicant). Yet, the literature is lacking in at least three areas: First, evidence from correspondence tests has primarily focused on middle-range wage earners, and little research exists on low-wage or high-wage earner positions. Second, research has looked at employment discrimination that excludes certain groups, but has neglected possible prejudice that “locks” such groups into unqualified or underpaid positions. Finally, there may also be a place-based effect – in which diverse communities are less discriminatory than more homogeneous communities, or vice versa. In this paper, we report on two population-level experiments with seven independent correspondence tests that were conducted in the Israel labor market, both designed to fill these three lags in the literature. We tested the likelihood of (a) Israeli-Arab lawyers versus Jewish lawyers being asked to job interviews at Israel’s largest law firms (n = 178); and (b) Mizrahi Jews versus Ashkenazi Jews being asked to job interviews, in any one of the registered security firms (n = 369). We compared which groups are more likely to be called for interviews and then meta-analyzed the results using standardized differences of means. Our findings suggest significant overall employment discrimination against both Arab-Israelis and Mizrahi Jews, whose applications are overall less likely to be both acknowledged by the prospective employers and asked for interview – despite the applicants having identical qualifications. However, we find that the effect in low-wage jobs is conditional on geographic location, with evidence to suggest that in some regions there is no preference toward either ethnicity. We find no support for a locking effect. We discuss the findings in the broader theoretical context, but suggest that a more granular application of the theory is called for, which takes into account community dynamics and the level of localized ethnic integration.

scholarly journals The growing Canadian energy gap: more the can than the couch?

2009 ◽  
Vol 12 (11) ◽  
pp. 2216-2224 ◽  
Author(s):  
Joyce Slater ◽  
Christopher G Green ◽  
Gustaaf Sevenhuysen ◽  
Barry Edginton ◽  
John O’Neil ◽  
...  
Keyword(s):  
Energy Gap ◽  
Population Level ◽  
Energy Availability ◽  
Adult Obesity ◽  
Balance Sheets ◽  
Available Energy ◽  
Relative Contribution ◽  
Canadian Population ◽  
Per Capita ◽  
Food Commodities

AbstractObjectiveThe present study describes the trajectory of the energy gap (energy imbalance) in the Canadian population from 1976 to 2003, its temporal relationship to adult obesity, and estimates the relative contribution of energy availability and expenditure to the energy gap. It also assesses which foods contributed the most to changes in available energy over the study period.DesignAnnual estimates of the energy gap were derived by subtracting population-adjusted per capita daily estimated energy requirements (derived from Dietary Reference Intakes) from per capita daily estimated energy available (obtained from food balance sheets). Food balance sheets were used to assess which foods contributed to changes in energy availability. Adult obesity rates were derived from six national surveys. The relationship to the energy gap was assessed through regression analysis.ResultsBetween 1976 and 2003, per capita daily estimated energy availability increased by 18 % (1744 kJ), and increased energy availability was the major driver of the increased energy gap. Salad oils, wheat flour, soft drinks and shortening accounted for the majority of the net increase in energy availability. Adult obesity was significantly correlated with the energy gap over the study period.ConclusionsThe widening energy gap is being driven primarily by increased energy availability. The food commodities driving the widening energy gap are major ingredients in many energy-dense convenience foods, which are being consumed with increasing frequency in Canada. Policies to address population obesity must have a strong nutritional focus with the objective of decreasing energy consumption at the population level.

scholarly journals Changes in the dollar value of per capita alcohol, essential, and non-essential retail sales in Canada during COVID-19

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Daniel T. Myran ◽  
Brendan T. Smith ◽  
Nathan Cantor ◽  
Lennon Li ◽  
Sudipta Saha ◽  
...  
Keyword(s):  
Time Series ◽  
Alcohol Use ◽  
Population Level ◽  
Interrupted Time Series ◽  
Interrupted Time Series Analysis ◽  
Retail Sales ◽  
Ongoing Research ◽  
Per Capita ◽  
Statistics Canada ◽  
Alcohol Sales

Abstract Background Multiple survey reports suggest that alcohol use has increased in Canada during the COVID-19 pandemic. However, less is known about how per capita alcohol sales, which predict population-level alcohol use, have changed and whether changes in alcohol sales differ from changes in sales of other products due to pandemic factors. Methods We obtained monthly retail sales data by industry from Statistics Canada, for the six largest provinces in Canada (containing 93% of the national population), between January 2010 and November 2020, representing time before and 9 months after the start of the pandemic in Canada. We used an interrupted time series analysis to estimate pandemic impacts on the dollar value of monthly per capita (per individuals 15+ years) alcohol, essential and non-essential retail sales. We adjusted our analyses for pre-pandemic sales trends, inflation, seasonality and changing population demographics over time. Results During the first 9 months of the pandemic, the values of per capita alcohol, essential and non-essential sales were, respectively, 13.2% higher, 3.6% higher and 13.1% lower than the average values during the same period in the prior 3 years. Interrupted time series models showed significant level change for the value of monthly per capita alcohol sales (+$4.86, 95% CIs: 2.88, 6.83), essential sales (−$59.80, 95% CIs: − 78.47, − 41.03) and non-essential sales (−$308.70, 95% CIs: − $326.60, − 290.79) during the pandemic. Alcohol sales were consistently elevated during the pandemic, and the pre- and post-pandemic slopes were comparable. In contrast, essential and non-essential retail sales declined in the early months of the pandemic before returning to regular spending levels. Conclusion During the first 9 months of the pandemic, per capita alcohol sales were moderately elevated in Canada. In contrast, non-essential sales were lower than prior years, driven by large decreases during the initial months of the pandemic. These findings suggest that the pandemic was associated with increased population-level alcohol consumption, which may lead to increased alcohol-related harms. Ongoing research is needed to examine how factors, including pandemic-related stressors and specific alcohol sales-related policies, may have influenced changes in alcohol use and harms.

scholarly journals Is the proportion of per capita fat supply associated with the prevalence of overweight and obesity? an ecological analysis

BMC Nutrition ◽  
2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Hasinthi Swarnamali ◽  
Ranil Jayawardena ◽  
Michail Chourdakis ◽  
Priyanga Ranasinghe
Keyword(s):  
Balance Sheet ◽  
National Income ◽  
Population Level ◽  
Overweight And Obesity ◽  
Strong Positive Correlation ◽  
Obesity Prevalence ◽  
Middle Income ◽  
Low Fat Diet ◽  
Per Capita ◽  
United Nations Food

Abstract Background Although it is reported in numerous interventional and observational studies, that a low-fat diet is an effective method to combat overweight and obesity, the relationship at the global population level is not well established. This study aimed to quantify the associations between worldwide per capita fat supply and prevalence of overweight and obesity and further classify this association based on per capita Gross National Income (GNI). Methods A total of 93 countries from four GNI groups were selected. Country-specific overweight and obesity prevalence data were retrieved from the most recent WHO Global Health Observatory database. Per capita supply of fat and calories were obtained from the United Nations Food and Agricultural Organization database; FAOSTAT, Food Balance Sheet for years 2014–2016. The categorizations of countries were done based on GNI based classification by the World Bank. Results Among the selected countries, the overweight prevalence ranged from 3.9% (India) to 78.8% (Kiribati), while obesity prevalence ranged from 3.6% (Bangladesh) to 46.0% (Kiribati). The highest and the lowest per capita fat supply from total calorie supply were documented in Australia (41.2%) and Madagascar (10.5%) respectively. A significant strong positive correlation was observed between the prevalence of overweight (r = 0.64, p < 0.001) and obesity (r = 0.59, p < 0.001) with per capita fat supply. The lower ends of both trend lines were densely populated by the low- and lower-middle-income countries and the upper ends of both lines were greatly populated by the high-income countries. Conclusions Per capita fat supply per country is significantly associated with both prevalence of overweight and obesity.

scholarly journals Health benefits and costs of weight-loss dietary counselling by nurses in primary care: a cost-effectiveness analysis

2019 ◽  
Vol 23 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Christine L Cleghorn ◽  
Nick Wilson ◽  
Nisha Nair ◽  
Giorgi Kvizhinadze ◽  
Nhung Nghiem ◽  
...  
Keyword(s):  
Primary Care ◽  
Weight Loss ◽  
Cost Effectiveness ◽  
Population Level ◽  
Cost Effective ◽  
Uncertainty Interval ◽  
Dietary Counselling ◽  
Life Years ◽  
Per Capita ◽  
The Impact

AbstractObjective:We aimed to estimate the cost-effectiveness of brief weight-loss counselling by dietitian-trained practice nurses, in a high-income-country case study.Design:A literature search of the impact of dietary counselling on BMI was performed to source the ‘best’ effect size for use in modelling. This was combined with multiple other input parameters (e.g. epidemiological and cost parameters for obesity-related diseases, likely uptake of counselling) in an established multistate life-table model with fourteen parallel BMI-related disease life tables using a 3 % discount rate.Setting:New Zealand (NZ).Participants:We calculated quality-adjusted life-years (QALY) gained and health-system costs over the remainder of the lifespan of the NZ population alive in 2011 (n 4·4 million).Results:Counselling was estimated to result in an increase of 250 QALY (95 % uncertainty interval −70, 560 QALY) over the population’s lifetime. The incremental cost-effectiveness ratio was 2011 $NZ 138 200 per QALY gained (2018 $US 102 700). Per capita QALY gains were higher for Māori (Indigenous population) than for non-Māori, but were still not cost-effective. If willingness-to-pay was set to the level of gross domestic product per capita per QALY gained (i.e. 2011 $NZ 45 000 or 2018 $US 33 400), the probability that the intervention would be cost-effective was 2 %.Conclusions:The study provides modelling-level evidence that brief dietary counselling for weight loss in primary care generates relatively small health gains at the population level and is unlikely to be cost-effective.

Sign in / Sign up

Export Citation Format

Share Document