scholarly journals Higher sociability leads to lower reproductive success in female kangaroos

2020 ◽  
Vol 7 (8) ◽  
pp. 200950
Author(s):  
C. S. Menz ◽  
A. J. Carter ◽  
E. C. Best ◽  
N. J. Freeman ◽  
R. G. Dwyer ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Social Relationships ◽  
Wild Population ◽  
Social Bonds ◽  
Group Living ◽  
Trade Offs ◽  
Fitness Consequences ◽  
Living Species ◽  
Complex Forms ◽  
First Time

In social mammals, social integration is generally assumed to improve females' reproductive success. Most species demonstrating this relationship exhibit complex forms of social bonds and interactions. However, female eastern grey kangaroos ( Macropus giganteus ) exhibit differentiated social relationships, yet do not appear to cooperate directly. It is unclear what the fitness consequences of such sociability could be in species that do not exhibit obvious forms of cooperation. Using 4 years of life history, spatial and social data from a wild population of approximately 200 individually recognizable female eastern grey kangaroos, we tested whether higher levels of sociability are associated with greater reproductive success. Contrary to expectations, we found that the size of a female's social network, her numbers of preferential associations with other females and her group sizes all negatively influenced her reproductive success. These factors influenced the survival of dependent young that had left the pouch rather than those that were still in the pouch. We also show that primiparous females (first-time breeders) were less likely to have surviving young. Our findings suggest that social bonds are not always beneficial for reproductive success in group-living species, and that female kangaroos may experience trade-offs between successfully rearing young and maintaining affiliative relationships.

scholarly journals Defense against outside competition is linked to cooperation in male–male partnerships

2019 ◽  
Vol 31 (2) ◽  
pp. 432-439
Author(s):  
Jennifer K Hellmann ◽  
Kelly A Stiver ◽  
Susan Marsh-Rollo ◽  
Suzanne H Alonzo
Keyword(s):  
Reproductive Success ◽  
Group Living ◽  
Dominant Male ◽  
Spawning Activity ◽  
Conflict And Cooperation ◽  
Behavioral Dynamics ◽  
Sexually Selected Traits ◽  
Before And After ◽  
Living Species ◽  
Selected Traits

Abstract Male–male competition is a well-known driver of reproductive success and sexually selected traits in many species. However, in some species, males work together to court females or defend territories against male competitors. Dominant (nesting) males sire most offspring, but subordinate (satellite) males are better able to obtain fertilizations relative to unpartnered males. Because satellites only gain reproductive success by sneaking, there has been much interest in identifying the mechanisms enforcing satellite cooperation (defense) and reducing satellite sneaking. One such potential mechanism is outside competition: unpartnered satellites can destabilize established male partnerships and may force partnered satellites to restrain from cheating to prevent the dominant male from replacing them with an unpartnered satellite. Here, we manipulated perceived competition in the Mediterranean fish Symphodus ocellatus by presenting an “intruding” satellite male to established nesting and satellite male pairs. Focal satellite aggression to the intruder was higher when focal satellites were less cooperative, suggesting that satellites increase aggression to outside competitors when their social position is less stable. In contrast, nesting male aggression to the intruder satellite increased as spawning activity increased, suggesting that nesting males increase their defense toward outside competitors when their current relationship is productive. We found no evidence of altered spawning activity or nesting/satellite male interactions before and after the presentation. These results collectively suggest that response to outside competition is directly linked to behavioral dynamics between unrelated male partners and may be linked to conflict and cooperation in ways that are similar to group-living species.

Age and experience affect the reproductive success of captive Loggerhead Shrike (Lanius ludovicianus) subspecies

2017 ◽  
Vol 95 (8) ◽  
pp. 547-554 ◽  
Author(s):  
T.L. Imlay ◽  
J.C. Steiner ◽  
D.M. Bird
Keyword(s):  
Reproductive Success ◽  
Wild Population ◽  
Trade Offs ◽  
Age Related ◽  
Captive Populations ◽  
Experienced Male ◽  
Lanius Ludovicianus ◽  
Fledgling Success ◽  
Loggerhead Shrike ◽  
Effect Of Age

Two explanations are often used to interpret the positive relationship between reproductive success and age: (1) trade-offs between current and future breeding and (2) age-related improvements in competence. Captive populations provide a unique opportunity to test these explanations because several mechanisms that result in age-related improvements in competence are managed. We modelled the effect of age and experience on the reproductive success of captive migrant Loggerhead Shrike (Lanius ludovicianus L., 1766) subspecies (formerly Lanius ludovicianus migrans W. Palmer, 1898). Female shrikes had the highest reproductive success during mid-life and lower success at 1–2 years of age and over 10 years. Both experienced male and female shrikes had higher fledgling success than inexperienced individuals. Although captive populations breed in controlled settings with few limitations, this work suggests that both explanations (i.e., trade-offs and age-related improvements in competence) are important for understanding reproductive success. Furthermore, management of the captive shrike population can be informed by these relationships to maximize the number of young produced for release to supplement the wild population.

scholarly journals Experimental disturbances reveal group-level costs of social instability

2018 ◽  
Vol 285 (1891) ◽  
pp. 20181577 ◽  
Author(s):  
A. A. Maldonado-Chaparro ◽  
G. Alarcón-Nieto ◽  
J. A. Klarevas-Irby ◽  
D. R. Farine
Keyword(s):  
Social Relationships ◽  
Group Living ◽  
Foraging Efficiency ◽  
Social Stability ◽  
Group Foraging ◽  
Social Instability ◽  
Living Species ◽  
Important Trait ◽  
Time Away ◽  
Animal Societies

In group-living species, social stability is an important trait associated with the evolution of complex behaviours such as cooperation. While the drivers of stability in small groups are relatively well studied, little is known about the potential impacts of unstable states on animal societies. Temporary changes in group composition, such as a social group splitting and recombining (i.e. a disturbance event), can result in individuals having to re-establish their social relationships, thus taking time away from other tasks such as foraging or vigilance. Here, we experimentally split socially stable groups of captive zebra finches ( Taeniopygia guttata ), and quantified the effects of repeated disturbance events on (1) group foraging efficiency, and (2) co-feeding associations when subgroups were recombined. We found that the efficiency of groups to deplete a rich, but ephemeral, resource patch decreased after just a single short disturbance event. Automated tracking of individuals showed that repeated disturbances reduced efficiency by causing social relationships to become more differentiated and weaker, resulting in fewer individuals simultaneously accessing the patch. Our experiment highlights how short-term disturbances can severely disrupt social structure and group functionality, revealing potential costs associated with group instability that can have consequences for the evolution of animal societies.

scholarly journals Parents face quantity–quality trade-offs between reproduction and investment in offspring in Iceland

2016 ◽  
Vol 3 (5) ◽  
pp. 160087 ◽  
Author(s):  
Robert Francis Lynch
Keyword(s):  
Reproductive Success ◽  
Evolutionary Biology ◽  
Fundamental Problem ◽  
Lifetime Reproductive Success ◽  
Trade Off ◽  
Evolutionary Conflict ◽  
Trade Offs ◽  
Fitness Consequences ◽  
Using Data ◽  
Primary Impact

How to optimally allocate time, energy and investment in an effort to maximize one's reproductive success is a fundamental problem faced by all organisms. This effort is complicated when the production of each additional offspring dilutes the total resources available for parental investment. Although a quantity–quality trade-off between producing and investing in offspring has long been assumed in evolutionary biology, testing it directly in humans is difficult, partly owing to the long generation time of our species. Using data from an Icelandic genealogy (Íslendingabók) over two centuries, I address this issue and analyse the quantity–quality trade-off in humans. I demonstrate that the primary impact of parents on the fitness of their children is the result of resources and or investment, but not genes. This effect changes significantly across time, in response to environmental conditions. Overall, increasing reproduction has negative fitness consequences on offspring, such that each additional sibling reduces an individual's average lifespan and lifetime reproductive success. This analysis provides insights into the evolutionary conflict between producing and investing in children while also shedding light on some of the causes of the demographic transition.

scholarly journals The fitness consequences of kin-biased dispersal in a cooperatively breeding bird

2015 ◽  
Vol 11 (7) ◽  
pp. 20150336 ◽  
Author(s):  
Lea Pollack ◽  
Dustin R. Rubenstein
Keyword(s):  
Social Rank ◽  
Group Living ◽  
Breeding Bird ◽  
Direct Benefits ◽  
Fitness Consequences ◽  
Cooperatively Breeding ◽  
Potential Benefits ◽  
Indirect Fitness ◽  
Living Species

Cooperative alliances among kin may not only lead to indirect fitness benefits for group-living species, but can also provide direct benefits through access to mates or higher social rank. However, the immigrant sex in most species loses any potential benefits of living with kin unless immigrants disperse together or recruit relatives into the group in subsequent years. To look for evidence of small subgroups of related immigrants within social groups (kin substructure), we used microsatellites to assess relatedness between immigrant females of the cooperatively breeding superb starling, Lamprotornis superbus. We determined how timing of immigration led to kin subgroup formation and if being part of one influenced female fitness. Although mean relatedness in groups was higher for males than females, 26% of immigrant females were part of a kin subgroup with a sister. These immigrant sibships formed through kin recruitment across years more often than through coalitions immigrating together in the same year. Furthermore, females were more likely to breed when part of a kin subgroup than when alone, suggesting that female siblings form alliances that may positively influence their fitness. Ultimately, kin substructure should be considered when determining the role of relatedness in the evolution of animal societies.

Socioecology of wild bearded capuchin monkeys (Sapajus libidinosus): an analysis of social relationships among female primates that use tools in feeding

Behaviour ◽  
2013 ◽  
Vol 150 (6) ◽  
pp. 659-689 ◽  
Author(s):  
Michele P. Verderane ◽  
Patrícia Izar ◽  
Elisabetta Visalberghi ◽  
Dorothy M. Fragaszy
Keyword(s):  
Social Relationships ◽  
Tool Use ◽  
Group Living ◽  
Contest Competition ◽  
Wild Populations ◽  
High Quality ◽  
Dominance Hierarchies ◽  
Living Species ◽  
Socioecological Models ◽  
Female Social Relationships

Socioecology considers that the features of food sources affect female social relationships in group-living species. Among primates, the tests of socioecological models are largely focused on Old World species and do not evaluate if the use of feeding tools affects the competitive regime over food and females’ relations in wild populations. We studied female social relationships among a wild population of bearded capuchins monkeys (Sapajus libidinosus) that use percussive tools (stones) to crack encased foods, in a semi-arid habitat in Brazil. Females fed mainly on clumped, high quality resources, indicating that the habitat provides a high quality diet year-round. Females experienced contest competition within and between-groups. As predicted by socioecological models, females’ social relationships were characterized by philopatry, linear dominance hierarchies, coalitions, and tolerance in feeding bouts. Females spent a small proportion of their feeding time using tools. Nevertheless, tool sites generated high rates of contest competition and lower indices of tolerance among females. Although the social structure of our study population did not differ significantly from the pattern observed in wild populations of Sapajus that do not use tools, tool use increased within-group contest competition and apparently contributed to the linearity of the dominance hierarchies established among females. We predict that when tool use results in usurpable food resources, it will increase contest competition within group-living species.

scholarly journals Winners have higher pre-copulatory mating success but losers have better post-copulatory outcomes

2019 ◽  
Vol 286 (1900) ◽  
pp. 20182838 ◽  
Author(s):  
David C. S. Filice ◽  
Reuven Dukas
Keyword(s):  
Reproductive Success ◽  
Fruit Fly ◽  
Choice Context ◽  
Trade Offs ◽  
Winner And Loser Effects ◽  
Fitness Consequences ◽  
Evolutionary Context ◽  
Variation Explained ◽  
Male Genotype ◽  
Copulatory Success

In many animals, the outcomes of competitive interactions can have lasting effects that influence an individual's reproductive success and have important consequences for the strength and direction of evolution via sexual selection. In the fruit fly, Drosophila melanogaster , males that have won previous contests are more likely to win in subsequent conflicts and losers are more likely to lose (winner–loser effects), but the direct fitness consequences and genetic underpinnings of this plasticity are poorly understood. Here, we tested how male genotype and the outcomes of previous male–male conflicts influence male pre- and post-copulatory success. We quantified pre-copulatory success in a choice and no-choice context, and post-copulatory success by quantifying ejaculate offensive and defensive ability. We found that winners have higher reproductive success compared to losers in both pre-copulatory scenarios. However, losers consistently mated for a longer duration, boosted female fecundity and had an increased paternity share when they were the first males to mate, suggesting increased investment into post-copulatory mechanisms. Finally, by using clonal hybrids from the Drosophila Genetic Reference Panel, we documented that genetic variation explained a sizeable proportion of the observed differences between lines, and of the interaction between line and winner and loser effects. Our results place the behavioural data on winner–loser effects in an evolutionary context by documenting the potential fitness gain to males from altering their reproductive strategy based on fighting experience. Our data may also explain the presence and maintenance of trade-offs between different male reproductive strategies.

scholarly journals Social-bond strength influences vocally mediated recruitment to mobbing

2016 ◽  
Vol 12 (11) ◽  
pp. 20160648 ◽  
Author(s):  
Julie M. Kern ◽  
Andrew N. Radford
Keyword(s):  
Bond Strength ◽  
Social Bonds ◽  
Social Groups ◽  
Group Living ◽  
Social Bond ◽  
Playback Experiments ◽  
Living Species ◽  
Fitness Benefits ◽  
Mobbing Behaviour

Strong social bonds form between individuals in many group-living species, and these relationships can have important fitness benefits. When responding to vocalizations produced by groupmates, receivers are expected to adjust their behaviour depending on the nature of the bond they share with the signaller. Here we investigate whether the strength of the signaller–receiver social bond affects response to calls that attract others to help mob a predator. Using field-based playback experiments on a habituated population of wild dwarf mongooses ( Helogale parvula ), we first demonstrate that a particular vocalization given on detecting predatory snakes does act as a recruitment call; receivers were more likely to look, approach and engage in mobbing behaviour than in response to control close calls. We then show that individuals respond more strongly to these recruitment calls if they are from groupmates with whom they are more strongly bonded (those with whom they preferentially groom and forage). Our study, therefore, provides novel evidence about the anti-predator benefits of close bonds within social groups.

scholarly journals Affiliative social relationships and coccidian oocyst excretion in a cooperatively breeding bird species

2017 ◽  
Author(s):  
Claudia A.F. Wascher ◽  
Daniela Canestrari ◽  
Vittorio Baglione
Keyword(s):  
Stress Response ◽  
Social Interactions ◽  
Social Relationships ◽  
Social Bonds ◽  
Bird Species ◽  
Group Living ◽  
Oocyst Excretion ◽  
Cooperatively Breeding ◽  
Nematode Eggs ◽  
Coccidian Oocyst

AbstractIn group living animals, behavioural interactions with conspecifics strongly modulate an individual’s physiological stress response. Stable social relationships may reduce an individual’s stress response, which in turn can affect the immune system and health. Ultimately, positive health effects of stable social bonds may contribute to maintain group living. We investigated whether, in cooperatively breeding carrion crows (Corvus corone), the quality of social relationships correlates with coccidian oocyst and nematode eggs excretion. We repeatably collected behavioural data on dyadic social interactions and individual droppings to quantify parasite eggs and oocysts from 36 individuals in a captive population of carrion crows in northern Spain. Individuals with strong social bonds, living with more relatives and in larger groups excreted a significantly smaller proportion of droppings containing coccidian oocysts. The probability to excrete droppings containing nematode eggs was not affected by social factors. The relationship between social interactions and coccidian oocyst excretion is consistent with the idea that high quality social relationships can positively affects individual’s health, setting the stage for the evolution of stable social living.

Affiliations, aggressions and an adoption: Male–male relationships in wild bonobos

2018 ◽  
Author(s):  
Martin Surbeck ◽  
Gottfried Hohmann
Keyword(s):  
Close Relationships ◽  
Group Living ◽  
Mate Competition ◽  
Male Group ◽  
Cooperative Hunting ◽  
Sexual Behaviours ◽  
Study Population ◽  
Living Species ◽  
The Way

The nature of the relationships between males is a characteristic trait of many multi-male group living species with implications for the individuals. In our study population of bonobos, certain male dyads exhibit clear preferences for ranging in the same party and sitting in proximity. These preferences are not reflected in the frequency of aggression towards each other and only to some extent in their affiliative and socio-sexual behaviours. While bonobo males at LuiKotale clearly do not benefit from close relationships in the way chimpanzee males do (cooperative hunting, territorial patrol, mate competition), some relationships might result from close associations between their mothers. In some particular situations, these male relationships can be very important as in the case of an orphan adopted by his older maternal brother. La nature des relations entre mâles est un trait caractéristique de plusieurs groupes qui ont plusieurs mâles, avec des implications au niveau d’individus. Dans notre étude des populations de bonobos, certains dyades mâles montrent une préférence à aller dans le même groupe et s’asseoir proche l’un de l’autre. Cette préférence n’est pas reflétée dans la fréquence d’agression entre eux et est seulement lié, à degrés, à leur comportements socio-sexuels et d’appartenance. Tandis que les mâles bonobos à LuiKotale ne profitent pas de leur fortes relations comme les chimpanzés mâles (chasse coopérative, patrouille territoriale, compétition pour compagnon), ils peuvent aider leur partenaires à supporter le stress de la vie en groupe et peuvent en conséquence contribuer au bien-être des individus. Quelques proches associations entre les mâles peuvent provenir d’associations entre leurs mères. Dans quelques situations particulières, ces relations mâles prouvent leur importance comme dans le cas d’un orphelin adopté par son grand frère maternel.

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