scholarly journals Role of sociality in the response of killer whales to an additive mortality event

2019 ◽  
pp. 201817174 ◽  
Author(s):  
Marine Busson ◽  
Matthieu Authier ◽  
Christophe Barbraud ◽  
Paul Tixier ◽  
Ryan R. Reisinger ◽  
...  
Keyword(s):  
Social Structure ◽  
Social Groups ◽  
Group Living ◽  
Foraging Success ◽  
Killer Whales ◽  
Negative Effects ◽  
Mortality Event ◽  
Individual Fitness ◽  
Fishing Vessels ◽  
Additive Mortality

In highly social top predators, group living is an ecological strategy that enhances individual fitness, primarily through increased foraging success. Additive mortality events across multiple social groups in populations may affect the social structure, and therefore the fitness, of surviving individuals. This hypothesis was examined in a killer whale (Orcinus orca) population that experienced a 7-y period of severe additive mortality due to lethal interactions with illegal fishing vessels. Using both social and demographic analyses conducted on a unique long-term dataset encompassing periods before, during, and after this event, results indicated a decrease in both the number and the mean strength of associations of surviving individuals during the additive mortality period. A positive significant correlation between association strength and apparent survival suggested that the fitness of surviving individuals was impacted by the additive mortality event. After this event, individuals responded to the loss of relatives in their social groups by associating with a greater number of other social groups, likely to maintain a functional group size that maximized their foraging success. However, these associations were loose; individuals did not reassociate in highly stable social groups, and their survival remained low years after the mortality event. These findings demonstrate how the disruption of social structure in killer whales may lead to prolonged negative effects of demographic stress beyond an additive mortality event. More importantly, this study shows that sociality has a key role in the resilience of populations to human-induced mortality; this has major implications for the conservation of highly social and long-lived species.

scholarly journals Family feud: permanent group splitting in a highly philopatric mammal, the killer whale (Orcinus orca)

2021 ◽  
Vol 75 (3) ◽  
Author(s):  
Eva H. Stredulinsky ◽  
Chris T. Darimont ◽  
Lance Barrett-Lennard ◽  
Graeme M. Ellis ◽  
John K. B. Ford
Keyword(s):  
Killer Whale ◽  
Group Structure ◽  
Group Living ◽  
Orcinus Orca ◽  
Learning Approaches ◽  
Killer Whales ◽  
Internal Factors ◽  
Individual Fitness ◽  
Leadership Experience

Abstract For animals that tend to remain with their natal group rather than individually disperse, group sizes may become too large to benefit individual fitness. In such cases, group splitting (or fission) allows philopatric animals to form more optimal group sizes without sacrificing all familiar social relationships. Although permanent group splitting is observed in many mammals, it occurs relatively infrequently. Here, we use combined generalized modeling and machine learning approaches to provide a comprehensive examination of group splitting in a population of killer whales (Orcinus orca) that occurred over three decades. Fission occurred both along and across maternal lines, where animals dispersed in parallel with their closest maternal kin. Group splitting was more common: (1) in larger natal groups, (2) when the common maternal ancestor was no longer alive, and (3) among groups with greater substructuring. The death of a matriarch did not appear to immediately trigger splitting. Our data suggest intragroup competition for food, leadership experience and kinship are important factors that influence group splitting in this population. Our approach provides a foundation for future studies to examine the dynamics and consequences of matrilineal fission in killer whales and other taxa. Significance statement Group living among mammals often involves long-term social affiliation, strengthened by kinship and cooperative behaviours. As such, changes in group membership may have significant consequences for individuals’ fitness and a population’s genetic structure. Permanent group splitting is a complex and relatively rare phenomenon that has yet to be examined in detail in killer whales. In the context of a growing population, in which offspring of both sexes remain with their mothers for life, we provide the first in-depth examination of group splitting in killer whales, where splitting occurs both along and across maternal lines. We also undertake the first comprehensive assessment of how killer whale intragroup cohesion is influenced by both external and internal factors, including group structure, population and group demography, and resource abundance.

scholarly journals Unreciprocated allogrooming hierarchies in a population of wild group-living mammals

2021 ◽  
Author(s):  
Catherine E Nadin ◽  
David W. Macdonald ◽  
Sandra Baker ◽  
Christina D. Buesching ◽  
Stephen Ellwood ◽  
...  
Keyword(s):  
Social Structure ◽  
Social Status ◽  
Dominance Rank ◽  
Social Groups ◽  
Group Living ◽  
Meles Meles ◽  
Social Species ◽  
Novel Approach ◽  
European Badgers ◽  
Wild Group

Allogrooming can relate to social status in mammalian societies, and thus, be used to infer social structure. This relationship has previously been investigated by examining an individual’s dominance rank and their total amount of allogrooming. This, however, does not account for the identity of allogrooming partners. We applied a novel approach, calculating the linearity and steepness of unreciprocated allogrooming hierarchies using actor–receiver matrices in European badgers (Meles meles) groups. Badgers have relatively unstructured social groups compared to most group-living carnivores and allogrooming in badgers is currently hypothesized to have a hygiene function. We examine whether allogrooming is linked to social status by investigating: 1) the presence, linearity, and steepness of unreciprocated allogrooming hierarchies; 2) the trading of unreciprocated allogrooming for the potential benefit of receiving reduced aggression from dominant individuals; and, 3) whether unreciprocated allogrooming is associated with relatedness. We found weak unreciprocated allogrooming hierarchies, with marginal linearity, steepness overall, and variation between social-group-years. Unreciprocated allogrooming was positively correlated with directed aggression, potentially providing evidence for the trading of allogrooming for reduced aggression. Allogrooming was not correlated with relatedness, possibly due to high relatedness within social groups. Our findings reaffirm that European badgers have a relatively unstructured social system; likely reflecting a relatively simple state of sociality in Carnivores, with little need for hierarchical order. Using actor–receiver unreciprocated allogrooming matrices to test for linearity and steepness of unreciprocated allogrooming hierarchies in other social species will improve knowledge of group social structure.

scholarly journals A natural catastrophic turnover event: individual sociality matters despite community resilience in wild house mice

2020 ◽  
Vol 287 (1926) ◽  
pp. 20192880
Author(s):  
Julian C. Evans ◽  
Jonas I. Liechti ◽  
Bruce Boatman ◽  
Barbara König
Keyword(s):  
Social Structure ◽  
Indirect Effects ◽  
Social Preferences ◽  
Group Membership ◽  
Social Groups ◽  
House Mice ◽  
Mus Musculus Domesticus ◽  
Individual Fitness ◽  
The Social ◽  
Wild House Mice

Natural disasters can cause rapid demographic changes that disturb the social structure of a population as individuals may lose connections. These changes also have indirect effects as survivors alter their within-group connections or move between groups. As group membership and network position may influence individual fitness, indirect effects may affect how individuals and populations recover from catastrophic events. Here we study changes in the social structure after a large predation event in a population of wild house mice ( Mus musculus domesticus ), when a third of adults were lost. Using social network analysis, we examine how heterogeneity in sociality results in varied responses to losing connections. We then investigate how these differences influence the overall network structure. An individual's reaction to losing associates depended on its sociality prior to the event. Those that were less social before formed more weak connections afterwards, while more social individuals reduced the number of survivors they associated with. Otherwise, the number and size of social groups were highly robust. This indicates that social preferences can drive how individuals adjust their social behaviour after catastrophic turnover events, despite the population's resilience in social structure.

scholarly journals A long post-reproductive lifespan is a shared trait among genetically distinct killer whale populations

2021 ◽  
Author(s):  
Mia Nielsen ◽  
Samuel Ellis ◽  
Jared Towers ◽  
Thomas Doniol-Valcroze ◽  
Daniel Franks ◽  
...  
Keyword(s):  
Social Structure ◽  
Killer Whale ◽  
Demographic Data ◽  
Reproductive Period ◽  
Substantial Variation ◽  
Killer Whales ◽  
Reproductive Conflict ◽  
Demographic Patterns ◽  
General Prediction

The extended female post-reproductive lifespan found in humans and some toothed whales remains an evolutionary puzzle. Theory predicts demographic patterns resulting in increased female relatedness with age (kinship dynamics) can select for a prolonged post-reproductive lifespan due to the combined costs of inter-generational reproductive conflict and benefits of late-life helping. Here we test this prediction using >40 years of longitudinal demographic data from the sympatric yet genetically distinct killer whale ecotypes: resident and Bigg’s killer whales. The female relatedness with age is predicted to increase in both ecotypes, but with a less steep increase in Bigg’s due to their different social structure. Here, we show that there is a significant post-reproductive lifespan in both ecotypes with >30% of adult female years being lived as post-reproductive, supporting the general prediction that an increase in local relatedness with age predisposes the evolution of a post-reproductive lifespan. Differences in the magnitude of kinship dynamics however, did not influence the timing or duration of the post-reproductive lifespan with females in both ecotypes terminating reproduction before their mid-40s followed by an expected post-reproductive period of ~20 years. Our results highlight the important role of kinship dynamics in the evolution of a long post-reproductive lifespan in long-lived mammals, while further implying that the timing of menopause may be a robust trait that is persistent despite substantial variation in demographic patterns among population.

Marine mammals and Japanese long-line fishing vessels in Australian waters: operational interactions and sightings

2006 ◽  
Vol 12 (1) ◽  
pp. 31 ◽  
Author(s):  
Catherine Bell ◽  
Peter Shaughnessy ◽  
Margie Morrice ◽  
Bob Stanley
Keyword(s):  
Marine Mammal ◽  
Marine Mammals ◽  
East Coast ◽  
Fishing Gear ◽  
Killer Whales ◽  
Fishing Vessels ◽  
Long Line ◽  
Target Fish ◽  
Pilot Whales ◽  
Warm Temperate

Observers from the Australian Fisheries Management Authority worked on randomly chosen Japanese long-line vessels in the Australian Fishing Zone (AFZ) between 1980 and 1997. Observer reports (n = 451) were inspected for interactions or sightings of marine mammals. An operational interaction was defined as an activity or behaviour that involved direct contact between a marine mammal and fishing gear, bait, target fish or bycatch, or indications that the marine mammal was feeding. A sighting was defined as the recording of marine mammals that passed the vessel without changing course and/or did not appear to interact with the vessel or its gear. Observers witnessed 23 interactions and made another 44 sightings of marine mammals. A further 24 interactions and sightings were relayed by crew members. Killer whales were reported most frequently: most incidences of fish being damaged, taken or frightened away were attributed to them. Eleven marine mammals were caught: two died, seven were released, and the fate of two others was not recorded. Between 1991 and 1996, when observer coverage was 11.5% overall in the AFZ, the incidence of interactions was 1.71 per million hooks set. The estimated number of interactions in that seven-year period was 157 in the AFZ. Since 1997, the long-line fishery has been conducted by Australian vessels, primarily off the east coast of mainland Australia in warm-temperate waters. A higher proportion of interactions can be expected with killer whales and short-finned pilot whales in these waters, and fewer with seals.

scholarly journals Asociación de Cooperativas Argentinas y Agricultores Federados Argentinos: dos buenos ejemplos de la transición en el cooperativismo agrario argentino

2019 ◽  
pp. 29-44
Author(s):  
Graciela Mateo
Keyword(s):  
Natural Environment ◽  
Social Groups ◽  
Mining Activities ◽  
Negative Effects ◽  
Liberal State ◽  
Royal Decree ◽  
Modern Age ◽  
Rivers And Streams ◽  
Natural Protection ◽  
Xix Century

Las cooperativas conforman una experiencia centenaria del agro argentino. En el siglo XXI, su desarrollo es uno de los principales ejes del Plan Estratégico Agroalimentario y Agroindustrial Participativo y Federal 2010-2020 para el logro de objetivos de competitividad y equidad social. Desde sus orígenes, el cooperativismo agrario procura cumplir con un doble objetivo: el primero, de carácter social, está destinado a la prestación de un servicio basado en principios de solidaridad, libre asociación y gestión democrática; el segundo, de carácter económico, está orientado a defender los intereses y mejorar la situación económica de sus asociados.Desde un criterio funcional, las cooperativas agrarias pueden cubrir diversas actividades, necesidades o servicios, tales como el aprovisionamiento, la producción, comercialización, la transformación o industrialización y el crédito, cumpliendo una o varias de esas fases. El artículo procura mostrar las transformaciones y permanencias operadas en el modelo cooperativo, a través del análisis de dos asociaciones emblemáticas del agro argentino: por un lado, la Asociación de Cooperativas Argentinas (ACA), primera entidad de segundo grado constituida en 1922 y que en la actualidad se encuentra entre los principales exportadores de cereales. Por otro, Agricultores Federados Argentinos (AFA), conformada en 1932 y que hoy es la principal cooperativa de primer grado del país. This paper analyzes the gestation of environmental protec-tion regulations related to mining activities, as well as specific mining provisions that were approved and had an impact to reduce the negative effects to the natural environment. The mining regulations that were approved in the Modern Age envisaged some measures in order to avoid damage to agri-culture, livestock and to villages in the environment of mining activities. In the XIX century, with a liberal State, several laws and mining regulations were slowly being adopted from the middle of the century, due to social conflicts, which introduced measures with health and natural protection effects. With a greater de-gree of state interventionism in the XX century, in a context of pressure from affected social groups, various sectoral rules for the protection of rivers and streams were approved. The Law of Mines in force introduced that it was approved by decree to fix the imperative conditions of protection of the environ-ment, being the origin of the first Royal Decree of restoration of mining activities of 1982.

Dynamics of the social structure of the Russian middle class

2016 ◽  
Vol 11 (3) ◽  
pp. 44-54
Author(s):  
Алексеенок ◽  
Anna Alekseenok ◽  
Гальцова ◽  
Anna Galtsova
Keyword(s):  
Middle Class ◽  
Social Structure ◽  
Social Groups ◽  
Value Orientations ◽  
Social Self ◽  
Self Assessment ◽  
Financial Position ◽  
The Social ◽  
The Status ◽  
Analysis Of Dynamics

The article presents a study of the dynamics of the social structure of the Russian middle class. It examines the dynamics of a number of different social groups in Russia in 2003-2014, «blocking» signs for the population which is not a member of the middle class, 2003-2014, self-assessment of the dynamics of 2014 and the possible dynamics for the next year of the financial position in the last year prior the survey in the different groups of the population. Also the analysis of dynamics of value orientations of different population groups, social identity, of the ways and the main types of leisure in the middle class is held. The article compares the model of Russian social structure, built on the basis of social self-assessment of the status of the Russian people in 2014 and 2000.

An uneasy alliance: unequal distribution of affiliative interactions among members of a captive wolf pack

2003 ◽  
Vol 81 (10) ◽  
pp. 1763-1766 ◽  
Author(s):  
Traci Cipponeri ◽  
Paul Verrell
Keyword(s):  
Canis Lupus ◽  
Social Groups ◽  
Alpha Male ◽  
Social Disruption ◽  
Unequal Distribution ◽  
Gray Wolves ◽  
Individual Fitness ◽  
Play Interactions ◽  
The Social ◽  
Time Of Breeding

The social groups of many vertebrates may be characterized as "uneasy alliances" that reflect tensions between benefits of group membership and costs to individual fitness among members, especially nonrelatives. The prebreeding season may be a time when these tensions become most acute and so observable for packs of gray wolves (Canis lupus). We recorded affiliative (play) interactions among two females and five males of known social ranks in a captive pack as the time of breeding approached. Substantial inequalities among pairs of wolves were apparent in frequencies of both the initiation of play and the exhibition of positive responses by recipient wolves. With the subsequent arrival of the breeding season, the pack experienced social disruption that led to the eviction of the original alpha male and a reordering of the ranks of those wolves remaining. Our data suggest that unequal affiliative interactions among pack members can be associated with (and, perhaps, even be predictive of) subsequent social disruption at a time when opportunities for personal reproduction become most available.

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