scholarly journals Social dominance hierarchy type and rank contribute to phenotypic variation within cages of laboratory mice

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Justin A. Varholick ◽  
Alice Pontiggia ◽  
Eimear Murphy ◽  
Vanessa Daniele ◽  
Rupert Palme ◽  
...  

Abstract A tacit assumption in laboratory animal research is that animals housed within the same cage or pen are phenotypically more similar than animals from different cages or pens, due to their shared housing environment. This assumption drives experimental design, randomization schemes, and statistical analysis plans, while neglecting social context. Here, we examined whether a domain of social context—social dominance—accounted for more phenotypic variation in mice than cage-identity. First, we determined that cages of mice could be categorized into one of three dominance hierarchies with varying degrees of dominance behavior between cage-mates, and low levels of agonistic behavior in the home-cage. Most groups formed dynamic hierarchies with unclear ranks, contrasting with recent accounts of stable transitive hierarchies in groups of mice. Next, we measured some phenotypic traits, and found that social dominance (i.e. dominance hierarchy type and degree of dominance behavior) consistently accounted for some phenotypic variation in all outcome measures, while cage-identity accounted for phenotypic variation in some measures but virtually no variation in others. These findings highlight the importance of considering biologically relevant factors, such as social dominance, in experimental designs and statistical plans.

Behaviour ◽  
2018 ◽  
Vol 155 (6) ◽  
pp. 443-463 ◽  
Author(s):  
Dawson M. Brown ◽  
Matthew S. Lattanzio

Abstract Intraspecific social dominance hierarchies should be influenced by environmental variation; however, in colour polymorphic species, dominance hierarchies are often assumed fixed, and thus insensitive to environmental variability. We ran a series of experiments using the colour polymorphic long-tailed brush lizard (Urosaurus graciosus) to challenge this assumption. We staged contests between orange and yellow morph males over a single heated perch, two perches at the same temperature, or two perches differing in temperature. Our first experiment revealed that orange-throated males are socially dominant. However, this hierarchy collapsed in our other experiments as yellow males became more aggressive. Interestingly, both males only ever secured their own perch where the perches differed in temperature. These findings mirror observations of morph behavioural flexibility in nature and studies of behaviour–environment interactions in non-polymorphic taxa. We conclude that colour morphs may have an underappreciated ability to assess resource-level changes and respond with concomitant flexibility in behaviour.


1970 ◽  
Vol 27 (2) ◽  
pp. 195-198 ◽  
Author(s):  
Carl W. Lawrence ◽  
Jack R. Haynes

Effects of epinephrine and nor-epinephrine on social dominance behavior in 24 male C57BL/6J mice were investigated. The social dominance hierarchy was created by placing pairs of Ss in a linear maze. The only way S could get to the goal box was by pushing the opposing S out. The dominant S pushed the submissive S out of the maze. After the dominance hierarchy was established, each S was placed in the dominance situation under each of the drug conditions, epinephrine and nor-epinephrine. The results showed that all conditions were significantly different from each other, with the greatest amount of dominance behavior being shown under nor-epinephrine and the greatest submissive behavior under epinephrine. It was concluded that epinephrine and nor-epinephrine may have differential effects on social dominance behavior.


1999 ◽  
Vol 202 (24) ◽  
pp. 3497-3506 ◽  
Author(s):  
F.A. Issa ◽  
D.J. Adamson ◽  
D.H. Edwards

The formation of social dominance hierarchies was studied in groups of five juvenile crayfish, 1.3-1.8 cm in length. Animals were grouped together in a small, featureless aquarium after having lived in isolation for more than a month. The occurrence of each of four behavior patterns (‘attack’, ‘approach’, ‘retreat’ and ‘escape’) was recorded for each animal, together with the frequency of encounters and the frequency of wins and losses. The frequencies of wins and losses were used to calculate the relative dominance value of each animal in the group. High levels of fighting developed immediately upon grouping the animals, and a positive feedback relationship between attacking and winning enabled one animal in each group to emerge quickly as the superdominant. If that animal was the largest, it remained as the superdominant; otherwise, it was replaced as superdominant within the first few days by the largest animal. This form of dominance hierarchy, with one superdominant and four subordinates, persisted throughout the duration of the grouping. Fighting declined over the first hour and by 24 h had dropped to low levels. After the first day, approaches were used together with attacks, and retreats replaced escapes. Attack and approach were the behavior patterns displayed most frequently by animals with high dominance values, whereas retreat and escape were performed by animals of low dominance. All these trends continued to develop over the next 2 weeks as the number of agonistic encounters declined to a low level.


2021 ◽  
Vol 15 ◽  
Author(s):  
Lucy K. Bicks ◽  
Michelle Peng ◽  
Alana Taub ◽  
Schahram Akbarian ◽  
Hirofumi Morishita

Social dominance hierarchies are a common adaptation to group living and exist across a broad range of the animal kingdom. Social dominance is known to rely on the prefrontal cortex (PFC), a brain region that shows a protracted developmental trajectory in mice. However, it is unknown to what extent the social dominance hierarchy is plastic across postnatal development and how it is regulated. Here we identified a sensitive period for experience-dependent social dominance plasticity in adolescent male mice, which is regulated by mechanisms that affect cortical plasticity. We show that social dominance hierarchies in male mice are already formed at weaning and are highly stable into adulthood. However, one experience of forced losing significantly reduces social dominance during the adolescent period but not in adulthood, suggesting adolescence as a sensitive period for experience-dependent social dominance plasticity. Notably, robust adolescent plasticity can be prolonged into adulthood by genetic deletion of Lynx1, a molecular brake that normally limits cortical plasticity through modulation of cortical nicotinic signaling. This plasticity is associated with increased activation of established nodes of the social dominance network including dorsal medial PFC and medial dorsal thalamus evidenced by increased c-Fos. Pharmacologically mediated elevation of cortical plasticity by valproic acid rapidly destabilizes the hierarchy of adult wildtype animals. These findings provide insight into mechanisms through which increased behavioral plasticity may be achieved to improve therapeutic recovery from psychiatric disorders that are associated with social deficits.


Behaviour ◽  
2007 ◽  
Vol 144 (7) ◽  
pp. 753-765 ◽  
Author(s):  
Adam Cronin ◽  
Jeremy Field

AbstractSocial aggression arises from conflicts of interest over reproduction in animal societies. Aggression is often highly variable between individuals in a group, may be correlated with dominance, and is often integral to the establishment of dominance hierarchies that in turn determine reproductive opportunities. However, reproductive dominance is not always linked with social dominance: 'queens' are not always the most aggressive individuals in a group. Furthermore, in some animals social rank is determined without aggression, and derived through another means, such as gerontocracy. In such instances, what is the role of aggression, and what underlies the variation between individuals? Here, we investigate the relationship between inheritance rank and aggression in the hover wasp Liostenogaster flavolineata, which has an age-based inheritance queue. All females in this study were of known age and, thus, rank could be determined independently of behaviour. Observations of intra-colony aggression indicated that aggression increased with inheritance rank and occurred among non-breeding subordinates. This cannot be explained by models that do not account for aggression between non-breeders. It is likely that contests over inheritance rank and the higher future fitness anticipated by high-ranking individuals account for this pattern.


2021 ◽  
Vol 118 (10) ◽  
pp. e2022912118
Author(s):  
Elizabeth A. Hobson ◽  
Dan Mønster ◽  
Simon DeDeo

Members of a social species need to make appropriate decisions about who, how, and when to interact with others in their group. However, it has been difficult for researchers to detect the inputs to these decisions and, in particular, how much information individuals actually have about their social context. We present a method that can serve as a social assay to quantify how patterns of aggression depend upon information about the ranks of individuals within social dominance hierarchies. Applied to existing data on aggression in 172 social groups across 85 species in 23 orders, it reveals three main patterns of rank-dependent social dominance: the downward heuristic (aggress uniformly against lower-ranked opponents), close competitors (aggress against opponents ranked slightly below self), and bullying (aggress against opponents ranked much lower than self). The majority of the groups (133 groups, 77%) follow a downward heuristic, but a significant minority (38 groups, 22%) show more complex social dominance patterns (close competitors or bullying) consistent with higher levels of social information use. These patterns are not phylogenetically constrained and different groups within the same species can use different patterns, suggesting that heuristic use may depend on context and the structuring of aggression by social information should not be considered a fixed characteristic of a species. Our approach provides opportunities to study the use of social information within and across species and the evolution of social complexity and cognition.


2020 ◽  
Author(s):  
Hong-Liang Lu ◽  
Yan-Fu Qu ◽  
Hong Li ◽  
Xiang Ji

Abstract Phenotypic plasticity and local adaptation are viewed as the main factors that result in between-population variation in phenotypic traits, but contributions of these factors to phenotypic variation vary between traits and between species and have only been explored in a few species of reptiles. Here, we incubated eggs of the Chinese skink (Plestiodon chinensis) from 7 geographically separated populations in Southeast China at 3 constant temperatures (24, 28, and 32 °C) to evaluate the combined effects of clutch origin, source population, and incubation temperature on hatchling traits. The relative importance of these factors varied between traits. Nearly all examined hatchling traits, including body mass, snout–vent length (SVL), tail length, head size, limb length, tympanum diameter, and locomotor speed, varied among populations and were affected by incubation temperature. Measures for hatchling size (body mass and SVL) varied considerably among clutches. Source population explained much of the variation in hatchling body mass, whereas incubation temperature explained much of the variation in other examined traits. Our results indicate that between-population variation in hatchling traits of P. chinensis likely reflects the difference in natural incubation conditions and genetic divergence.


1966 ◽  
Vol 6 (5) ◽  
pp. 207-208 ◽  
Author(s):  
B. N. Bunnell ◽  
J. R. Bemporad ◽  
Carol K. Flesher

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1633 ◽  
Author(s):  
Suzanna M. Evans ◽  
Elizabeth A. Sinclair ◽  
Alistair G.B. Poore ◽  
Keryn F. Bain ◽  
Adriana Vergés

Declines in genetic diversity within a species can affect the stability and functioning of populations. The conservation of genetic diversity is thus a priority, especially for threatened or endangered species. The importance of genetic variation, however, is dependent on the degree to which it translates into phenotypic variation for traits that affect individual performance and ecological processes. This is especially important for predominantly clonal species, as no single clone is likely to maximise all aspects of performance. Here we show that intraspecific genotypic diversity as measured using microsatellites is a strong predictor of phenotypic variation in morphological traits and shoot productivity of the threatened, predominantly clonal seagrassPosidonia australis, on the east coast of Australia. Biomass and surface area variation was most strongly predicted by genotypic richness, while variation in leaf chemistry (phenolics and nitrogen) was unrelated to genotypic richness. Genotypic richness did not predict tissue loss to herbivores or epiphyte load, however we did find that increased herbivore damage was positively correlated with allelic richness. Although there was no clear relationship between higher primary productivity and genotypic richness, variation in shoot productivity within a meadow was significantly greater in more genotypically diverse meadows. The proportion of phenotypic variation explained by environmental conditions varied among different genotypes, and there was generally no variation in phenotypic traits among genotypes present in the same meadows. Our results show that genotypic richness as measured through the use of presumably neutral DNA markers does covary with phenotypic variation in functionally relevant traits such as leaf morphology and shoot productivity. The remarkably long lifespan of individualPosidoniaplants suggests that plasticity within genotypes has played an important role in the longevity of the species. However, the strong link between genotypic and phenotypic variation suggests that a range of genotypes is still the best case scenario for adaptation to and recovery from predicted environmental change.


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