Nest predation predicts infanticide in a cooperatively breeding bird

In cooperatively breeding species, social conflict is typically assumed to underlie destructive behaviours like infanticide. However, an untested alternative hypothesis in birds is that infanticide in the form of egg tossing may simply be a parental response to partial nest predation representing a life-history trade-off. We examined egg tossing behaviour in the colonial and cooperatively breeding grey-capped social weaver ( Pseudonigrita arnaudi ), a plural breeder in which pairs nest separately, often in the same tree. Using infrared nest cameras, we found that 78% of the tossing events from 2012 to 2017 were committed by parents, suggesting that social conflict is unlikely to be the main reason underlying egg tossing in this species. Instead, reductions in clutch size due to both natural and experimentally simulated predation induced parental egg tossing. Our study suggests that destructive behaviour in cooperatively breeding birds can be shaped by a variety of mechanisms beyond social conflict and that alternative hypotheses must be considered when studying the adaptive significance of infanticide in group-living species.

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

Biology Letters ◽

10.1098/rsbl.2015.0336 ◽

2015 ◽

Vol 11 (7) ◽

pp. 20150336 ◽

Cited By ~ 7

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.

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A test of male infanticide as a reproductive tactic in a cichlid fish

Royal Society Open Science ◽

10.1098/rsos.160891 ◽

2017 ◽

Vol 4 (3) ◽

pp. 160891 ◽

Cited By ~ 3

Author(s):

Shagun Jindal ◽

Aneesh P. H. Bose ◽

Constance M. O'Connor ◽

Sigal Balshine

Keyword(s):

Cichlid Fish ◽

Group Living ◽

Laboratory Setting ◽

Dominant Position ◽

Egg Cannibalism ◽

Cooperatively Breeding ◽

Dominant Individual ◽

Living Species ◽

Reproductive Tactic ◽

Relative Body Size

Infanticide and offspring cannibalism are taxonomically widespread phenomena. In some group-living species, a new dominant individual taking over a group can benefit from infanticide if doing so induces potential mates to become reproductively available sooner. Despite widespread observations of infanticide (i.e. egg cannibalism) among fishes, no study has investigated whether egg cannibalism occurs in fishes as a result of group takeovers, or how this type of cannibalism might be adaptive. Using the cooperatively breeding cichlid, Neolamprologus pulcher , we tested whether new unrelated males entering the dominant position in a social group were more likely to cannibalize eggs, and whether such cannibalism would shorten the interval until the female's next spawning. Females spawned again sooner if their broods were removed than if they were cared for. Egg cannibalism occurred frequently after a group takeover event, and was rarer if the original male remained with the group. While dominant breeder females were initially highly aggressive towards newcomer males that took over the group, the degree of resistance depended on relative body size differences between the new pair and, ultimately, female aggression did not prevent egg cannibalism. Egg cannibalism, however, did not shorten the duration until subsequent spawning, or increase fecundity during subsequent breeding in our laboratory setting. Our results show that infanticide as mediated through group takeovers is a taxonomically widespread behaviour.

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Social monitoring via close calls in meerkats

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.1013 ◽

2013 ◽

Vol 280 (1765) ◽

pp. 20131013 ◽

Cited By ~ 15

Author(s):

Stephan A. Reber ◽

Simon W. Townsend ◽

Marta B. Manser

Keyword(s):

Group Living ◽

Common Mechanism ◽

Suricata Suricatta ◽

Social Monitoring ◽

Current State ◽

Dominant Female ◽

Cooperatively Breeding ◽

Living Species ◽

Group Members ◽

And Control

Social monitoring of the actions of group members is thought to be a key development associated with group living. Humans constantly monitor the behaviour of others and respond to them in a flexible way depending on past interactions and the current social context. While other primates have also been reported to change their behaviour towards other group members flexibly based on the current state of their relationship, empirical evidence is typically linked to contextually specific events such as aggressive or reproductive interactions. In the cooperatively breeding meerkat ( Suricata suricatta ), we investigated whether subordinate females use frequently emitted, non-agonistic close calls to monitor the location of the dominant female and whether they subsequently adjust their response based on recent social interactions during conflict and non-conflict periods. Subjects discriminated between the close calls of the dominant female and control playbacks, responding by approaching the loudspeaker and displaying submissive behaviour only if they were currently threatened by eviction. Our results suggest that meerkats assess the risk for aggressive interactions with close associates depending on social circumstances, and respond accordingly. We argue that social monitoring based on non-agonistic cues is probably a common mechanism in group-living species that allows the adjustment of behaviour depending on variation in relationships.

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Variable fledging age according to group size: trade-offs in a cooperatively breeding bird

Biology Letters ◽

10.1098/rsbl.2007.0435 ◽

2007 ◽

Vol 3 (6) ◽

pp. 624-627 ◽

Cited By ~ 24

Author(s):

N.J Raihani ◽

A.R Ridley

Keyword(s):

Group Size ◽

Group Living ◽

Breeding Bird ◽

Communal Roost ◽

Trade Offs ◽

Efficient Detection ◽

Risk Of Predation ◽

Cooperatively Breeding ◽

Individual Survival ◽

Dilution Effects

Group living can provide individuals with several benefits, including cooperative vigilance and lower predation rates. Individuals in larger groups may be less vulnerable to predation due to dilution effects, efficient detection or greater ability to repel predators. Individuals in smaller groups may consequently employ alternative behavioural tactics to compensate for their greater vulnerability to predators. Here, we describe how pied babbler ( Turdoides bicolor ) fledging age varies with group size and the associated risk of nestling predation. Nestling predation is highest in smaller groups, but there is no effect of group size on fledgling predation. Consequently, small groups fledge young earlier, thereby reducing the risk of predation. However, there is a cost to this behaviour as younger fledglings are less mobile than older fledglings: they move shorter distances and are less likely to successfully reach the communal roost tree. The optimal age to fledge young appears to depend on the trade-off between reduced nestling predation and increased fledgling mobility. We suggest that such trade-offs may be common in species where group size critically affects individual survival and reproductive success.

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Acorn woodpeckers vocally discriminate current and former group members from nongroup members

Behavioral Ecology ◽

10.1093/beheco/araa059 ◽

2020 ◽

Vol 31 (5) ◽

pp. 1120-1128 ◽

Cited By ~ 2

Author(s):

Michael A Pardo ◽

Casey E Hayes ◽

Eric L Walters ◽

Walter D Koenig

Keyword(s):

Social Relationships ◽

Group Living ◽

Current Group ◽

Breeding Bird ◽

Cooperatively Breeding ◽

Melanerpes Formicivorus ◽

Group Members ◽

Valuable Relationships ◽

Acorn Woodpeckers

Abstract In species with long-term social relationships, the ability to recognize individuals after extended separation and the ability to discriminate between former social affiliates that have died and those that have left the group but may return are likely to be beneficial. Few studies, however, have investigated whether animals can make these discriminations. We presented acorn woodpeckers (Melanerpes formicivorus), a group-living, cooperatively breeding bird, with playbacks of current group members, former group members still living nearby, former group members that had died or left the study area, and familiar nongroup members. Subjects responded more quickly to the calls of nongroup members than to the calls of current group members or former group members still living in the study area but did not discriminate between nongroup members and former group members that had died or disappeared. This suggests that acorn woodpeckers can vocally recognize both current group members and former group members that have dispersed to nearby groups and that they either forget former group members that no longer live in the vicinity or classify them differently from former group members that still live nearby. This study suggests an important role for vocal recognition in maintaining valuable relationships with social affiliates postdispersal.

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Faculty Opinions recommendation of Inclusive fitness consequences of dispersal decisions in a cooperatively breeding bird, the long-tailed tit (Aegithalos caudatus).

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.734375884.793556827 ◽

2019 ◽

Author(s):

Per Smiseth

Keyword(s):

Inclusive Fitness ◽

Breeding Bird ◽

Fitness Consequences ◽

Cooperatively Breeding ◽

Aegithalos Caudatus

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

10.1093/oso/9780198728511.003.0003 ◽

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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Social ethology of the wolverine

10.1093/oso/9780198759805.003.0018 ◽

2018 ◽

Author(s):

Jeffrey P. Copeland ◽

Arild Landa ◽

Kimberly Heinemeyer ◽

Keith B. Aubry ◽

Jiska van Dijk ◽

...

Keyword(s):

Social Organization ◽

Social Interactions ◽

Resource Availability ◽

Social Behaviour ◽

Social System ◽

Group Living ◽

Field Studies ◽

Ecological Framework ◽

The Social ◽

Living Species

Social behaviour in solitary carnivores has long been an active area of investigation but for many species remains largely founded in conjecture compared to our understanding of sociality in group-living species. The social organization of the wolverine has, until now, received little attention beyond its portrayal as a typical mustelid social system. In this chapter the authors compile observations of social interactions from multiple wolverine field studies, which are integrated into an ecological framework. An ethological model for the wolverine is proposed that reveals an intricate social organization, which is driven by variable resource availability within extremely large territories and supports social behaviour that underpins offspring development.

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