Artificial mass loading disrupts stable social order in pigeon dominance hierarchies

Dominance hierarchies confer benefits to group members by decreasing the incidences of physical conflict, but may result in certain lower ranked individuals consistently missing out on access to resources. Here, we report a linear dominance hierarchy remaining stable over time in a closed population of birds. We show that this stability can be disrupted, however, by the artificial mass loading of birds that typically comprise the bottom 50% of the hierarchy. Mass loading causes these low-ranked birds to immediately become more aggressive and rise-up the dominance hierarchy; however, this effect was only evident in males and was absent in females. Removal of the artificial mass causes the hierarchy to return to its previous structure. This interruption of a stable hierarchy implies a strong direct link between body mass and social behaviour and suggests that an individual's personality can be altered by the artificial manipulation of body mass.

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Structure of the Dominance Hierarchy and Dominance Determining "Group Factors" in Melanochromis Auratus (Pisces, Cichlidae)

Behaviour ◽

10.1163/156853985x00280 ◽

1985 ◽

Vol 94 (1-2) ◽

pp. 85-107 ◽

Cited By ~ 34

Author(s):

Mark H.J. Nelissen

Keyword(s):

Dominance Hierarchy ◽

Cichlid Fish ◽

Aggressive Interaction ◽

Group Factor ◽

Dominance Relations ◽

Group Life ◽

Determining Factors ◽

Representative Model ◽

Group Members ◽

Linear Dominance Hierarchy

AbstractTwo questions are asked: (1) Which relation is there between the dominance hierarchy and communication? (2) Which are the dominance determining factors that are a result of group life ("group factors") and that cannot be found in pairs of animals? Melanochromis auratus, a cichlid fish from Lake Malawi, is studied under laboratory conditions as a representative model. Dominance relations in pairs of animals differ from those (between the same fishes) in groups of conspecifics. In groups M. auratus establishes and maintains a linear dominance hierarchy, of which the communicative structure is described and discussed. The number of aggressive interactions between two group members, is determined by the rank number of the actor and the reactor. Most interactions occur between rank neighbours. "Group factors" are looked for by analysing the clustering of all possible chase-interactions. Four categories of such clusterings are discussed: a preceding aggressive interaction can have an influence on high-ranked animals, the effect of such an influence is directed towards low-ranked animals. The stable hierarchy can be changed by successive circle fights. The highest-ranked group members always intervene in circle fights in order to stabilize the hierarchy, for their own benefit. This is another "group factor". An alpha animal has to spend all its energy in obtaining and maintaining its rank status. When it looses this position, it drops down the hierarchy. The benefit of the alpha place could be the reproductive succes.

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Hierarchical development of dominance through the winner-loser effect and socio-spatial structure

10.1101/2020.12.01.406017 ◽

2020 ◽

Author(s):

E.S. van Haeringen ◽

C.K. Hemelrijk

Keyword(s):

Spatial Structure ◽

Analytical Methods ◽

Dominance Hierarchy ◽

Alternative Explanation ◽

Spatial Location ◽

Similar Degree ◽

Complete Model ◽

Dominance Hierarchies ◽

High Linearity ◽

Group Members

AbstractIn many groups of animals the dominance hierarchy is linear. What mechanisms underlie this linearity of the dominance hierarchy is under debate. Linearity is often attributed to cognitively sophisticated processes, such as transitive inference and eavesdropping. An alternative explanation is that it develops via the winner-loser effect. This effect implies that after a fight has been decided the winner is more likely to win again, and the loser is more likely to lose again. Although it has been shown that dominance hierarchies may develop via the winner-loser effect, the degree of linearity of such hierarchies is unknown.The aim of the present study is to investigate whether a similar degree of linearity, like in real animals, may emerge as a consequence of the winner-loser effect and the socio-spatial structure of group members. For this purpose, we use the model DomWorld, in which agents group and compete and the outcome of conflicts are self-reinforcing. Here dominance hierarchies are shown to emerge. In the model, we apply analytical methods previously used in a study on dominance in real hens including an analysis of behaviourial dynamics and network triad motifs.We show that when in the complete model one parameter, representing the intensity of aggression, was set high, the model reproduced the high linearity and many patterns of hierarchical development typical of groups of hens. Yet, when omitting from the model the winner-loser effect or spatial location of individuals, this resemblance decreased markedly.Our results demonstrate that the spatial structure and the winner-loser effect provide a plausible alternative for hierarchical linearity to processes that are cognitively more sophisticated. Further research should determine whether the winner-loser effect and spatial structure of group members also explains the characteristics of hierarchical development in other species.

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Aggressive behaviour in groups of domesticated pigs on removal and return of individuals

Animal Science ◽

10.1017/s0003356100000179 ◽

1971 ◽

Vol 13 (4) ◽

pp. 685-693 ◽

Cited By ~ 82

Author(s):

R. Ewbank ◽

G. B. Meese

Keyword(s):

Social Order ◽

Dominance Hierarchy ◽

Social Rank ◽

Feeding Time ◽

Dominance Order ◽

Immature Female ◽

Large White ◽

The Social ◽

Social Orders ◽

Linear Dominance Hierarchy

SUMMARYSeveral groups of eight fattening (18 kg to 91 kg) Large White pigs containing both immature female and castrated male animals were established, were fed twice a day on a commercial dry ration, were observed at feeding time and their social orders (linear dominance hierarchy) worked out. Individual pigs were removed, one at a time, from different places in the social order, isolated for varying periods of time, and then replaced in their groups. It was found that the removal of a pig from any rank in the dominance order altered neither the basic social hierarchy nor the amount of aggression within the remainder of the group. The duration of time that an animal could be removed, isolated and returned without being attacked by the rest of its group varied with its social rank. Top-ranking animals could be safely returned even after 25 days' isolation, but lowranking animals were severely attacked after only 3 days' absence.

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The prevalence of underweight in 9–10-year-old schoolchildren in Liverpool: 1998–2006

Public Health Nutrition ◽

10.1017/s136898000800311x ◽

2009 ◽

Vol 12 (7) ◽

pp. 953-956 ◽

Cited By ~ 13

Author(s):

Lynne M Boddy ◽

Allan F Hackett ◽

Gareth Stratton

Keyword(s):

Mass Spectrum ◽

Body Mass ◽

The Body ◽

Fitness Testing ◽

Policy Makers ◽

Substantial Problem ◽

Prevalence Of Obesity ◽

Grade 3 ◽

The City ◽

Over Time

AbstractObjectiveTo estimate the prevalence of underweight between 1998 and 2006 in Liverpool schoolchildren aged 9–10 years using recently published underweight cut-off points.Design and settingStature and body mass data collected at the LiverpoolSportsLinx project’s fitness testing sessions were used to calculate BMI.SubjectsData were available on 26 782 (n13 637 boys, 13 145 girls) participants.ResultsOverall underweight declined in boys from 10·3 % in 1998–1999 to 6·9 % in 2005–2006, and all sub-classifications of underweight declined, in particular grade 3 underweight, with the most recent prevalence being 0·1 %. In girls, the prevalence of underweight declined from 10·8 % in 1998–1999 to 7·5 % in 2005–2006. The prevalence of all grades of underweight was higher in girls than in boys. Underweight showed a fluctuating pattern across all grades over time for boys and girls, and overall prevalence in 2005–2006 represents over 200 children across the city.ConclusionsUnderweight may have reduced slightly from baseline, but remains a substantial problem in Liverpool, with the prevalence of overall underweight being relatively similar to the prevalence of obesity. The present study highlights the requirement for policy makers and funders to consider both ends of the body mass spectrum when fixing priorities in child health.

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Non-random associations in group housed rats (Rattus norvegicus)

Scientific Reports ◽

10.1038/s41598-021-94608-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Leanne Proops ◽

Camille A. Troisi ◽

Tanja K. Kleinhappel ◽

Teresa Romero

Keyword(s):

Network Analysis ◽

Empirical Evidence ◽

Rattus Norvegicus ◽

Dominance Hierarchy ◽

Group Living ◽

Ecological Factors ◽

Limited Evidence ◽

Rat Strains ◽

Social Species ◽

Over Time

AbstractEcological factors, such as predation, have traditionally been used to explain sociability. However, it is increasingly recognised that individuals within a group do not associate randomly, and that these non-random associations can generate fitness advantages. The majority of the empirical evidence on differentiated associations in group-living mammals, however, comes from a limited number of taxa and we still know very little about their occurrence and characteristics in some highly social species, such as rats (Rattus spp.). Here, using network analysis, we quantified association patterns in four groups of male fancy rats. We found that the associations between rats were not randomly distributed and that most individuals had significantly more preferred/avoided associates than expected by random. We also found that these preferences can be stable over time, and that they were not influenced by individuals’ rank position in the dominance hierarchy. Our findings are consistent with work in other mammals, but contrast with the limited evidence available for other rat strains. While further studies in groups with different demographic composition are warranted to confirm our findings, the occurrence of differentiated associations in all male groups of rats have important implications for the management and welfare of captive rat populations.

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Heritability of Longitudinal Measures of Body Mass Index and Lipid and Lipoprotein Levels in Aging Twins

Twin Research and Human Genetics ◽

10.1375/twin.10.5.703 ◽

2007 ◽

Vol 10 (5) ◽

pp. 703-711 ◽

Cited By ~ 52

Author(s):

Ellen L. Goode ◽

Stacey S. Cherny ◽

Joe C. Christian ◽

Gail P. Jarvik ◽

Mariza de Andrade

Keyword(s):

Body Mass Index ◽

Body Mass ◽

Genetic Factors ◽

Significant Proportion ◽

Lipoprotein Cholesterol ◽

Equation Modeling ◽

Shared Environment ◽

Significant Contributor ◽

Age Related ◽

Over Time

AbstractBody-mass index (BMI), total cholesterol (TC), lowdensity lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG) levels are known to be highly heritable. We evaluated the genetic and environmental relationships of these measures over time in an analysis of twin pairs. Monozygotic (235 pairs) and dizygotic (260 pairs) male twins were participants in the National Heart Lung and Blood Institute Veteran Twin Study, and were followed with three clinical exams from mean age 48 years to mean age 63 years. Structural equation modeling (SEM) with adjustment forAPOEgenotype (a significant contributor to TC and LDL-C) was used to assess longitudinal patterns of heritability. Results indicated a contribution of genetic factors to BMI, TC, LDL-C, HLD-C, and TG. Modest increases over time were observed in the heritability of BMI (from 0.48 to 0.61), TC (from 0.46 to 0.57), LDL-C (from 0.49 to 0.64), and HDL-C (from 0.50 to 0.62), but this trend was not present for TG. There was a corresponding decrease in shared environmental influences over time for these traits, although shared environment was a significant contributor only for HDL-C. Moreover, we observed that genetic influences for all measures were significantly correlated over time, and we found no evidence of age-specific genetic effects. In summary, longitudinal analyses of twin data indicate that genetic factors do not account for a significant proportion of the variation in age-related changes of BMI or lipid and lipoprotein levels.

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Homology-Based Interactions between Small RNAs and Their Targets Control Dominance Hierarchy of Male Determinant Alleles of Self-Incompatibility in Arabidopsis lyrata

International Journal of Molecular Sciences ◽

10.3390/ijms22136990 ◽

2021 ◽

Vol 22 (13) ◽

pp. 6990

Author(s):

Shinsuke Yasuda ◽

Risa Kobayashi ◽

Toshiro Ito ◽

Yuko Wada ◽

Seiji Takayama

Keyword(s):

Dominance Hierarchy ◽

Male Dominance ◽

Self Incompatibility ◽

Arabidopsis Halleri ◽

Plant Family ◽

Arabidopsis Lyrata ◽

Multiple Networks ◽

Target Sites ◽

Gains And Losses ◽

Linear Dominance Hierarchy

Self-incompatibility (SI) is conserved among members of the Brassicaceae plant family. This trait is controlled epigenetically by the dominance hierarchy of the male determinant alleles. We previously demonstrated that a single small RNA (sRNA) gene is sufficient to control the linear dominance hierarchy in Brassica rapa and proposed a model in which a homology-based interaction between sRNAs and target sites controls the complicated dominance hierarchy of male SI determinants. In Arabidopsis halleri, male dominance hierarchy is reported to have arisen from multiple networks of sRNA target gains and losses. Despite these findings, it remains unknown whether the molecular mechanism underlying the dominance hierarchy is conserved among Brassicaceae. Here, we identified sRNAs and their target sites that can explain the linear dominance hierarchy of Arabidopsis lyrata, a species closely related to A. halleri. We tested the model that we established in Brassica to explain the linear dominance hierarchy in A. lyrata. Our results suggest that the dominance hierarchy of A. lyrata is also controlled by a homology-based interaction between sRNAs and their targets.

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Proactive prosociality in a cooperatively breeding corvid, the azure-winged magpie ( Cyanopica cyana )

Biology Letters ◽

10.1098/rsbl.2016.0649 ◽

2016 ◽

Vol 12 (10) ◽

pp. 20160649 ◽

Cited By ~ 28

Author(s):

Lisa Horn ◽

Clara Scheer ◽

Thomas Bugnyar ◽

Jorg J. M. Massen

Keyword(s):

Cooperative Breeding ◽

Cooperatively Breeding ◽

Group Members ◽

Over Time

One of the contemporary hypotheses concerning the evolution of human altruism is the cooperative breeding hypothesis (CBH) which has recently been tested in non-human primates. Using a similar paradigm, we investigated prosociality in a cooperatively breeding corvid, the azure-winged magpie. We found that the magpies delivered food to their group members at high rates, and unlike other corvids, they did so without any cues provided by others. In two control conditions, the magpies stopped participating over time, indicating that they learned to discriminate prosocial tests from controls. Azure-winged magpies are thus the first birds that experimentally show proactive prosociality. Our findings are in line with the CBH; however, additional corvid species need to be tested in this promising paradigm.

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Analysis of Body Mass Index (BMI) Trends Among a Pediatric Dental Patient Population: A Pilot Study. (Preprint)

10.2196/preprints.31104 ◽

2021 ◽

Author(s):

Tengfei Su ◽

Mac Jackson ◽

Keaton Sacry ◽

Karl Kingsley MPH

Keyword(s):

Body Mass Index ◽

Body Mass ◽

Low Income ◽

Patient Population ◽

Pediatric Population ◽

Primary Care Providers ◽

Overweight And Obesity ◽

Dental School ◽

Care Providers ◽

Over Time

BACKGROUND Over the past few decades, a growing trend of overweight and obesity has emerged among the pediatric population. This is a cause of significant concern as these are significantly correlated to other negative oral and systemic health outcomes over time. Although measurement of body mass index (BMI) is common among pediatric physicians and primary care providers, few studies have explored the feasibility of BMI measurement and analysis from pediatric dental providers. OBJECTIVE The primary objective of this study was to compile and analyze pediatric BMI measurements taken from a pediatric dental school patient population. METHODS This study was a retrospective analysis of previously collected data of pediatric patients between 2012 and 2019 (N=451), which was reviewed and approved by the Institutional Review Board (IRB). Descriptive statistics and trend analysis were compiled to determine the trends in pediatric BMI over time. RESULTS Nearly equal percentages of females and males were represented in the study (P=0.432), with the overwhelming majority identified as racial/ethnic minorities (84.5%), P=0.0075. These data revealed that pediatric BMI increased significantly from 25.6 in 2012 to 31.3 in 2018 (22.1%), P=0.031. No significant differences between males and females were observed (P=0.4824) or between minority and non-minority patients (P=0.8288). CONCLUSIONS This study provides significant novel temporal information regarding pediatric BMI among this low-income, minority patient population and highlights the need for expanding the dental school (and pediatric dental residency) curriculum to include more topics related to measuring and tracking overweight and obese children and the most appropriate methods for use in the pediatric dental office.

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Self-organizing dominance hierarchies in a wild primate population

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2015.1512 ◽

2015 ◽

Vol 282 (1814) ◽

pp. 20151512 ◽

Cited By ~ 33

Author(s):

Mathias Franz ◽

Emily McLean ◽

Jenny Tung ◽

Jeanne Altmann ◽

Susan C. Alberts

Keyword(s):

Individual Differences ◽

Social Dynamics ◽

Experimental Studies ◽

Self Organization ◽

Social Self ◽

Dominance Hierarchies ◽

Change Over Time ◽

Winner And Loser Effects ◽

The Social ◽

Over Time

Linear dominance hierarchies, which are common in social animals, can profoundly influence access to limited resources, reproductive opportunities and health. In spite of their importance, the mechanisms that govern the dynamics of such hierarchies remain unclear. Two hypotheses explain how linear hierarchies might emerge and change over time. The ‘prior attributes hypothesis’ posits that individual differences in fighting ability directly determine dominance ranks. By contrast, the ‘social dynamics hypothesis’ posits that dominance ranks emerge from social self-organization dynamics such as winner and loser effects. While the prior attributes hypothesis is well supported in the literature, current support for the social dynamics hypothesis is limited to experimental studies that artificially eliminate or minimize individual differences in fighting abilities. Here, we present the first evidence supporting the social dynamics hypothesis in a wild population. Specifically, we test for winner and loser effects on male hierarchy dynamics in wild baboons, using a novel statistical approach based on the Elo rating method for cardinal rank assignment, which enables the detection of winner and loser effects in uncontrolled group settings. Our results demonstrate (i) the presence of winner and loser effects, and (ii) that individual susceptibility to such effects may have a genetic basis. Taken together, our results show that both social self-organization dynamics and prior attributes can combine to influence hierarchy dynamics even when agonistic interactions are strongly influenced by differences in individual attributes. We hypothesize that, despite variation in individual attributes, winner and loser effects exist (i) because these effects could be particularly beneficial when fighting abilities in other group members change over time, and (ii) because the coevolution of prior attributes and winner and loser effects maintains a balance of both effects.

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