scholarly journals A model of sexual selection and female use of refuge in a coercive mating system

2012 ◽  
Vol 279 (1741) ◽  
pp. 3209-3216
Author(s):  
Dessa Bokides ◽  
Yuan Lou ◽  
Ian M. Hamilton
Keyword(s):  
Total Population ◽  
Relative Number ◽  
Threshold Level ◽  
Male Harassment ◽  
Male Phenotype ◽  
Males And Females ◽  
Selection For ◽  
Coercive Mating ◽  
The Relationship ◽  
Number Of Males

In many non-monogamous systems, males invest less in progeny than do females. This leaves males with higher potential rates of reproduction, and a likelihood of sexual conflict, including, in some systems, coercive matings. If coercive matings are costly, the best female strategy may be to avoid male interaction. We present a model that demonstrates female movement in response to male harassment as a mechanism to lower the costs associated with male coercion, and the effect that female movement has on selection in males for male harassment. We found that, when females can move from a habitat patch to a refuge to which males do not have access, there may be a selection for either high, or low harassment male phenotype, or both, depending on the relationship between the harassment level of male types in the population and a threshold level of male harassment. This threshold harassment level depends on the relative number of males and females in the population, and the relative resource values of the habitat; the threshold increases as the sex ratio favours females, and decreases with the value of the refuge patch or total population. Our model predicts that selection will favour the harassment level that lies closest to this threshold level of harassment, and differing harassment levels will coexist within the population only if they lie on the opposite sides of the threshold harassment. Our model is consistent with empirical results suggesting that an intermediate harassment level provides maximum reproductive fitness to males when females are mobile.

scholarly journals VARIATION IN NEMEOPHILA PETROSA AT LAGGAN IN WESTERN ALBERTA

1895 ◽  
Vol 27 (4) ◽  
pp. 87-93
Author(s):  
Thomas E. Bean
Keyword(s):  
Early Stage ◽  
Relative Number ◽  
Great Majority ◽  
Common Occurrence ◽  
Night Temperature ◽  
Natural Conditions ◽  
Open Ground ◽  
Males And Females ◽  
Number Of Males

At 5,000 feet altitude, in the vicinity of Laggan, Nemeophila petrosaflies during July. This is one of our commoner moths, and appears to be the only bombycid of common occurrence in the district. Although occasionally round near timber 1ine, it is rare at that elevation. Under natural conditions only one flight occurs in the season, and larvæ from eggs of that flight hibernate principally at an early stage. In the house, with a warmer night temperature, larvæ resultant from the July flight will go to imago late in October instead of hibernating. Inthe wild environment, a second flight is prevented by the low night temperature. Petrosa frequents moist banks, ditches, margins of old roads, and open ground well supplied with plants. A great majority of the individuals seen in flight are males, the disparity in relative number of males and females observed resulting from the quieter disposition of the females. The males are very restless and readily take flight, thereby attracting observation.

scholarly journals Hermaphrodites and parasitism: size-specific female reproduction drives infection by an ephemeral parasitic castrator

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Caitlin R. Fong ◽  
Armand M. Kuris ◽  
Ryan F. Hechinger
Keyword(s):  
Reproductive Effort ◽  
Reproductive Function ◽  
Simultaneous Hermaphrodite ◽  
Female Reproduction ◽  
Female Function ◽  
Males And Females ◽  
Selection For ◽  
Parasitic Castrator ◽  
Male Reproductive Effort ◽  
The Relationship

AbstractSex can influence patterns of parasitism because males and females can differ in encounter with, and susceptibility to, parasites. We investigate an isopod parasite (Hemioniscus balani) that consumes ovarian fluid, blocking female function of its barnacle host, a simultaneous hermaphrodite. As a hermaphrodite, sex is fluid, and individuals may allocate energy differentially to male versus female reproduction. We predicted the relationship between barnacle size and female reproductive function influences the distribution of parasites within barnacle populations. We surveyed 12 populations spanning ~400 km of coastline of southern California and found intermediate-sized barnacles where most likely to be actively functioning as females. While it is unclear why larger individuals are less likely to be actively reproducing as females, we suggest this reduced likelihood is driven by increased investment in male reproductive effort at larger sizes. The female function-size relationship was mirrored by the relationship between size and parasitism. We suggest parasitism by Hemioniscus balani imposes a cost to female function, reinforcing the lack of investment in female function by the largest individuals. Within the subset of suitable (=female) hosts, infection probability increased with size. Hence, the distribution of female function, combined with selection for larger hosts, primarily dictated patterns of infection.

On the evolutionary stability of male harassment in a coercive mating game

2016 ◽  
Vol 47 (1) ◽  
Author(s):  
Oyita Udiani ◽  
Yuan Lou ◽  
Ian Hamilton
Keyword(s):  
Habitat Preferences ◽  
Threshold Level ◽  
Mating Strategies ◽  
Social Environments ◽  
Resource Quality ◽  
Globally Asymptotically Stable ◽  
Male Harassment ◽  
Behavioral Adaptations ◽  
Low Levels ◽  
Coercive Mating

In many animals, males employ coercive mating strategies to help them maximize their expected number of offspring. In such systems, selection will favor behavioral adaptations in females that help them mitigate harassment costs and maximize their reproductive fitness. Previously, Bokides et al. [1] presented a model showing how male harassment strategies can co-evolve with female habitat preferences in a mating game. Their results indicated that if females dispersed freely between habitats where males were present and where males were excluded, selection could favor males who strategically harassed at high (or low) levels, depending on the proximity of their phenotype to a threshold level $h^*$. This article is a continuation of that work addressing the questions of stability at equilibria where males harass at the threshold level (i.e., $h^*$). We show these states are both locally and globally asymptotically stable. Further, we argue based on these results that $h^*$ is an evolutionary stable male harassment level at which females will be ideally distributed to match the resource quality and social environments of their alternative habitats.

Operational Sex Ratios in Seahorses

Behaviour ◽  
1994 ◽  
Vol 128 (1-2) ◽  
pp. 153-167 ◽  
Author(s):  
Amanda C.J. Vincent
Keyword(s):  
Relative Number ◽  
Reproductive Rate ◽  
Operational Sex Ratio ◽  
Laboratory Population ◽  
Sri Lankan ◽  
Males And Females ◽  
Male Pregnancy ◽  
Reproductive Rates ◽  
Number Of Males ◽  
Operational Sex Ratios

AbstractContrary to all expectations based on their male pregnancy, recent work shows that seahorses exhibit conventional sex roles in mating competition: male seahorses compete more to obtain eggs than females do to give their eggs away. This suggests that the operational sex ratio (OSR: the relative number of males and females available to mate) might be male-biased despite the length and limitations of male pregnancy. I here report a study of a laboratory population of the Sri Lankan seahorse Hippocampus fuscus. The OSR amongst mated seahorses is unbiased because males and females effectively have equal reproductive rates, although some evidence suggests that a female may have limited potential for a higher reproductive rate than her partner. In contrast, the OSR among mate-seeking seahorses is male-biased, because unmated (empty) males can prepare to mate more quickly and can remain ready to mate for longer than can unmated females. Thus, the OSR is male-biased in exactly that segment of the population which should compete for mates. These findings are compatible with the sexually monogamous mating pattern of many seahorse species.

Attachment and Field Dependence: Individual Differences in Information Processing

2004 ◽  
Vol 9 (1) ◽  
pp. 43-55 ◽  
Author(s):  
Patrizia Vermigli ◽  
Alessandro Toni
Keyword(s):  
Information Processing ◽  
Individual Differences ◽  
Field Dependence ◽  
Attachment Styles ◽  
Close Relationships ◽  
Adult Age ◽  
Males And Females ◽  
Figure Test ◽  
The Relationship ◽  
Measure Field

The present research analyzes the relationship between attachment styles at an adult age and field dependence in order to identify possible individual differences in information processing. The “Experience in Close Relationships” test of Brennan et al. was administered to a sample of 380 individuals (160 males, 220 females), while a subsample of 122 subjects was given the Embedded Figure Test to measure field dependence. Confirming the starting hypothesis, the results have shown that individuals with different attachment styles have a different way of perceiving the figure against the background. Ambivalent and avoidant individuals lie at the two extremes of the same dimension while secure individuals occupy the central part. Significant differences also emerged between males and females.

Career Adaptability and Career Decision Self-Efficacy: Meta-Analysis

2021 ◽  
pp. 089484532110124
Author(s):  
Graham B. Stead ◽  
Lindsey M. LaVeck ◽  
Sandra M. Hurtado Rúa
Keyword(s):  
Self Efficacy ◽  
Total Population ◽  
Meta Analysis ◽  
Career Decision ◽  
Decision Making Process ◽  
Career Adaptability ◽  
Efficacy Measures ◽  
Meta Analyses ◽  
Career Research ◽  
The Relationship

The relationship between career adaptability and career decision self-efficacy was examined due to its importance for clients in the career development and career decision-making process. Multivariate meta-analyses using 18 studies with a total population of 6,339 participants were employed. Moderator variables important to this relationship were country of participants, mean age, and career adaptability measures. Estimated correlations between career adaptability subscales and career decision self-efficacy measures ranged from .36 to .44. Findings are discussed in relation to career research and counseling.

scholarly journals Does Revitalizing the Center of Mid-Sized French Cities Reduce GHG Emissions from Commuting?

2021 ◽  
Vol 13 (4) ◽  
pp. 1851
Author(s):  
Alexis Poulhès ◽  
Angèle Brachet
Keyword(s):  
Land Use Planning ◽  
Statistical Models ◽  
Total Population ◽  
Ghg Emissions ◽  
Low Carbon ◽  
Trip Distance ◽  
Working People ◽  
Shrinking City ◽  
The Relationship ◽  
Positive Effect

Mid-sized cities are usually considered in the literature to be shrinking cities. Some policies promote right-sizing and others promote revitalization. The relationship between land-use planning and mobility having been established, the present research issue is focused on whether a policy of revitalizing the centers of mid-sized cities is favorable to low-carbon mobility. Our study investigates commuting trips through two indicators: commuting trip distance and car modal share. The increase in total population, the increase in the number of jobs per resident, the decrease in the unemployment rate, the increase in the rate of executives, the increase in the rate of working people in the population and the decrease in the residential vacancy rate all come from the censuses of 2006 and 2016. Statistical models based on individuals in 113 mid-sized cities, in which sociodemographic variables are introduced, show that at the level of agglomerations, no indicator has a simultaneously positive effect in the center and in the urban periphery. No indicator is entirely positive or negative on GHG emissions from commuting trips. While the increase in GHG emissions from commuting trips between 2006 and 2016 is significant in mid-sized cities (18%), a shift toward shrinking city centers is insufficient to change this trajectory.

Binge Eating and Addictive-Like Behaviours in Males and Females

2020 ◽  
pp. 003329412097175
Author(s):  
Johanna Levallius ◽  
Elin Monell ◽  
Andreas Birgegård ◽  
David Clinton ◽  
Emma Forsén Mantilla
Keyword(s):  
Gender Differences ◽  
Binge Eating ◽  
Disordered Eating ◽  
Food Addiction ◽  
Community Sample ◽  
Eating Behaviours ◽  
Compulsive Exercise ◽  
Males And Females ◽  
Common Behaviour ◽  
The Relationship

Introduction Binge eating is a common behaviour that is strongly linked to both obesity and eating disorder. There is evidence that binge eating commonly co-occurs with other problematic and addictive-like behaviours; however, this has not been explored systematically. The present study aimed to examine the relationship between binge eating, body weight, disordered eating behaviours and associated addictive-like behaviours, with particular attention paid to gender differences. Method A community sample ( N = 500; 75% female, Mage = 32.5 years) reported disordered eating behaviours (i.e. binge eating, purging, restriction of eating, compulsive exercise), body mass index (BMI), food addiction, starvation addiction, exercise dependence, tobacco use and alcohol consumption. Results 42% of females and 21% of males reported binge eating during the past four weeks. Binge eating was significantly associated with all investigated behaviours in females, and with purging, compulsive exercise and overweight/obesity in males. Controlling for BMI, self-starvation predicted binge eating in males (OR = 1.07), while food addiction (OR = 1.73) and alcohol dependence (OR = 1.11) predicted binge eating in females. Conclusions The multiple associations between binge eating and addictive-like behaviors supports broad screening and generalized prevention efforts. Prevention efforts should reflect gender differences.

scholarly journals Physiological, Biochemical, and Growth Parameters of Fogera Cattle Calves to Heat Stress during Different Seasons in Sub-Humid Part of Ethiopia

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1062
Author(s):  
Michael Abera ◽  
Yesihak Yusuf Mummed ◽  
Mitiku Eshetu ◽  
Fabio Pilla ◽  
Zewdu Wondifraw
Keyword(s):  
Heat Stress ◽  
Growth Parameters ◽  
Hematological Parameters ◽  
Average Temperature ◽  
High Weight Gain ◽  
Different Seasons ◽  
Current Production ◽  
Humidity Index ◽  
Males And Females ◽  
Number Of Males

Fogera cattle are among indigenous breeds of cattle in the northern part of Ethiopia. However, their response to heat stress (HS) under different seasonal variations has not been well investigated. This study was aimed to determine physiological, hematological, biochemical, and growth parameters of Fogera cattle calves to HS during dry season, short rainy, and long rainy. A total of 72 calves (24 for each season) that were 6 months of age with an equal number of males and females were evaluated for physiological, hematological, biochemical, and growth parameters. Daily ambient temperature (AT) and relative humidity (RH) were recorded two times per day during the study periods from which the daily average temperature–humidity index (THI) was calculated. The study revealed higher AT and THI during dry and short seasons while higher RH was observed during the long rainy season. Physiological parameters except rectal temperature were affected by the seasons. Hematological parameters were also affected by season except for packed cell volume. Biochemical and growth parameters were also significantly affected by the seasons. THI was positively related with physiological but negatively with growth parameters. Thus, the THI value of 66 can be considered as optimum for high weight gain and normal physiological response to HS in Fogera cattle calves under their current production system.

EEG-correlates of work efficiency level among young persons with stress-induced bruxism

2021 ◽  
pp. 25-29
Author(s):  
A. E. Barulin ◽  
S. V. Klauchek ◽  
A. E. Klauchek
Keyword(s):  
Regression Models ◽  
Alpha Rhythm ◽  
Negative Relationship ◽  
Maximum Amplitude ◽  
Dominant Frequency ◽  
Regression Equations ◽  
Microsoft Excel ◽  
The Subject ◽  
Males And Females ◽  
The Relationship

Purpose of the study. To establish the relationship between neurophysiological status and the level of efficiency in young people with bruxism.Materials and methods. Two groups of 64 and 53 subjects (males and females) aged 20–35 years old with bruxism and non-bruxers were formed according to questionnaire results and physical examination. The level of efficiency was assessed by the results of sensorimotor tracking of a moving object (the ‘Smile’ model). Spectral analysis was performed for evaluation of the baseline electroencephalograms. Microsoft Excel and Statistica 10.0 programs were used for statistical data processing.Results. The level of efficiency was statistically significantly lower in the hardest test of Smile model among the individuals with bruxism (p < 0.05). The bruxers also demonstrated a significantly lower dominant frequency and maximum amplitude of alpha-rhythm (p < 0.05), and significantly higher dominant frequency of beta2 rhythm (p < 0.05). The dominant frequency and the maximum amplitude of the alpha-rhythm are parameters corresponding to significant coefficients of the regression analysis. A negative relationship was found between the degree of error during sensorimotor tracking and the frequency and amplitude of alpha-rhythm.Conclusion. Regression models present the relationship between the level of efficiency and the alpha-rhythm severity. The regression equations make it possible to determine the functional state of the subject using an electroencephalogram.

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