scholarly journals Food sharing in vampire bats: reciprocal help predicts donations more than relatedness or harassment

2013 ◽  
Vol 280 (1753) ◽  
pp. 20122573 ◽  
Author(s):  
Gerald G. Carter ◽  
Gerald S. Wilkinson
Keyword(s):  
Kin Selection ◽  
Kin Recognition ◽  
Social Bonding ◽  
Food Sharing ◽  
Past Work ◽  
Vampire Bats ◽  
Helping Behaviour ◽  
Indirect Fitness ◽  
Fitness Benefits ◽  
Recognition Errors

Common vampire bats often regurgitate food to roost-mates that fail to feed. The original explanation for this costly helping behaviour invoked both direct and indirect fitness benefits. Several authors have since suggested that food sharing is maintained solely by indirect fitness because non-kin food sharing could have resulted from kin recognition errors, indiscriminate altruism within groups, or harassment. To test these alternatives, we examined predictors of food-sharing decisions under controlled conditions of mixed relatedness and equal familiarity. Over a 2 year period, we individually fasted 20 vampire bats ( Desmodus rotundus ) and induced food sharing on 48 days. Surprisingly, donors initiated food sharing more often than recipients, which is inconsistent with harassment. Food received was the best predictor of food given across dyads, and 8.5 times more important than relatedness. Sixty-four per cent of sharing dyads were unrelated, approaching the 67 per cent expected if nepotism was absent. Consistent with social bonding, the food-sharing network was consistent and correlated with mutual allogrooming. Together with past work, these findings support the hypothesis that food sharing in vampire bats provides mutual direct fitness benefits, and is not explained solely by kin selection or harassment.

Kin selection in Columbian ground squirrels: direct and indirect fitness benefits

2011 ◽  
Vol 21 (3) ◽  
pp. 524-531 ◽  
Author(s):  
F. STEPHEN DOBSON ◽  
VINCENT A. VIBLANC ◽  
COLINE M. ARNAUD ◽  
JAN O. MURIE
Keyword(s):  
Kin Selection ◽  
Ground Squirrels ◽  
Indirect Fitness ◽  
Fitness Benefits ◽  
Columbian Ground Squirrels

scholarly journals Kinship affects investment by helpers in a cooperatively breeding bird

2010 ◽  
Vol 277 (1698) ◽  
pp. 3299-3306 ◽  
Author(s):  
Ki-Baek Nam ◽  
Michelle Simeoni ◽  
Stuart P. Sharp ◽  
Ben J. Hatchwell
Keyword(s):  
Cooperative Breeding ◽  
Kin Selection ◽  
Genetic Relatedness ◽  
Critical Role ◽  
Breeding Systems ◽  
Pedigree Information ◽  
Breeding Bird ◽  
Cooperatively Breeding ◽  
Indirect Fitness ◽  
Fitness Benefits

Helping behaviour in cooperative breeding systems has been attributed to kin selection, but the relative roles of direct and indirect fitness benefits in the evolution of such systems remain a matter of debate. In theory, helpers could maximize the indirect fitness benefits of cooperation by investing more in broods with whom they are more closely related, but there is little evidence for such fine-scale adjustment in helper effort among cooperative vertebrates. In this study, we used the unusual cooperative breeding system of the long-tailed tit Aegithalos caudatus to test the hypothesis that the provisioning effort of helpers was positively correlated with their kinship to broods. We first use pedigrees and microsatellite genotypes to characterize the relatedness between helpers and breeders from a 14 year field study. We used both pedigree and genetic approaches because long-tailed tits have access to pedigree information acquired through social relationships, but any fitness consequences will be determined by genetic relatedness. We then show using both pedigrees and genetic relatedness estimates that alloparental investment by helpers increases as their relatedness to the recipients of their care increases. We conclude that kin selection has played a critical role in moulding the investment decisions of helpers in this cooperatively breeding species.

Male relatedness, lekking behavior patterns, and the potential for kin selection in a Neotropical hummingbird

The Auk ◽  
2019 ◽  
Vol 136 (3) ◽  
Author(s):  
Clementina González ◽  
Juan Francisco Ornelas
Keyword(s):  
Reproductive Success ◽  
Kin Selection ◽  
Inclusive Fitness ◽  
Isolation By Distance ◽  
Behavior Patterns ◽  
Song Type ◽  
Selection Theory ◽  
Indirect Fitness ◽  
Fitness Benefits ◽  
Gain Access

AbstractSeveral models have been proposed to explain the evolution of leks, both in terms of direct or indirect fitness benefits, and in survival. According to kin selection theory, male skewed reproductive success leads unsuccessful males to join successful relatives to increase their inclusive fitness, because their genes would be transmitted indirectly to the next generation. Wedge-tailed Sabrewing (Campylopterus curvipennis) is a hummingbird species whose males congregate at leks, in which spatially clustered males sing a particular song with marked differences among neighboring males (song neighborhoods). The maintenance of song neighborhoods presumably depends on juvenile newcomers copying the song type of their neighbors when they establish within a lek, and their acceptance could be more likely if a relative has already settled down in a territory, which in turn could offer fitness benefits explained by kin selection theory. To investigate the potential for kin selection in this species, we genotyped 126 hummingbirds at 10 microsatellite loci and estimated pairwise relatedness among males at 6 leks and in 4 song neighborhoods within 1 focal lek. Within leks, most males were unrelated and only a few were relatives. Moreover, even though relatedness within leks was higher than between leks, it was not higher than 0, which is likely due to isolation by distance. Our results do not support the idea of kin selection as an important force acting on the formation of leks in this species. Additionally, we found no evidence for kin clustering within song neighborhoods, suggesting that juveniles attempting to settle in a lek have to learn the song of the neighborhood (regardless of their kinship) to gain access to territories.

scholarly journals Kin selection and polygyny: can relatedness lower the polygyny threshold?

2015 ◽  
Vol 2 (6) ◽  
pp. 140409 ◽  
Author(s):  
Gaute Grønstøl ◽  
Donald Blomqvist ◽  
Angela Pauliny ◽  
Richard H. Wagner
Keyword(s):  
Dna Fingerprinting ◽  
Kin Selection ◽  
Inclusive Fitness ◽  
Nest Defence ◽  
Natal Philopatry ◽  
Vanellus Vanellus ◽  
Indirect Fitness ◽  
Fitness Benefits ◽  
Breeding Resources

Resource polygyny incurs costs of having to share breeding resources for female breeders. When breeding with a relative, however, such costs may be lessened by indirect fitness benefits through kin selection, while benefits from mutualistic behaviour, such as communal defence, may increase. If so, females should be less resistant to sharing a territory with a related female than with a non-related one. We investigated whether kin selection may lower the threshold of breeding polygynously, predicting a closer relatedness between polygynous females breeding on the same territory than between females breeding on different territories. Northern lapwings, Vanellus vanellus , are suitable for testing this hypothesis as they are commonly polygynous, both sexes take part in nest defence, and the efficiency of nest defence increases with the number of defenders. Using an index of relatedness derived from DNA fingerprinting, we found that female lapwings that shared polygynous dyads were on average twice as closely related as were random females. Furthermore, relatedness did not correlate with distance between breeders, indicating that our findings cannot be explained by natal philopatry alone. Our results suggest that the polygyny threshold in lapwings may be lowered by inclusive fitness advantages of kin selection.

scholarly journals Sex, long life and the evolutionary transition to cooperative breeding in birds

2015 ◽  
Vol 282 (1816) ◽  
pp. 20151663 ◽  
Author(s):  
Philip A. Downing ◽  
Charlie K. Cornwallis ◽  
Ashleigh S. Griffin
Keyword(s):  
Cooperative Breeding ◽  
Group Living ◽  
Typical Feature ◽  
Evolution Of Cooperation ◽  
Female Promiscuity ◽  
Helping Behaviour ◽  
Indirect Fitness ◽  
Fitness Benefits ◽  
Long Life ◽  
The Relationship

Long life is a typical feature of individuals living in cooperative societies. One explanation is that group living lowers mortality, which selects for longer life. Alternatively, long life may make the evolution of cooperation more likely by ensuring a long breeding tenure, making helping behaviour and queuing for breeding positions worthwhile. The benefit of queuing will, however, depend on whether individuals gain indirect fitness benefits while helping, which is determined by female promiscuity. Where promiscuity is high and therefore the indirect fitness benefits of helping are low, cooperation can still be favoured by an even longer life span. We present the results of comparative analyses designed to test the likelihood of a causal relationship between longevity and cooperative breeding by reconstructing ancestral states of cooperative breeding across birds, and by examining the effect of female promiscuity on the relationship between these two traits. We found that long life makes the evolution of cooperation more likely and that promiscuous cooperative species are exceptionally long lived. These results make sense of promiscuity in cooperative breeders and clarify the importance of life-history traits in the evolution of cooperative breeding, illustrating that cooperation can evolve via the combination of indirect and direct fitness benefits.

scholarly journals Social benefits of non-kin food sharing by female vampire bats

2015 ◽  
Vol 282 (1819) ◽  
pp. 20152524 ◽  
Author(s):  
Gerald G. Carter ◽  
Gerald S. Wilkinson
Keyword(s):  
Treatment Period ◽  
Inclusive Fitness ◽  
Food Sharing ◽  
Social Benefits ◽  
Adult Females ◽  
Vampire Bats ◽  
Indirect Fitness ◽  
Alternative Responses ◽  
Close Relatives

Regurgitations of blood among vampire bats appear to benefit both direct and indirect fitness. To maximize inclusive fitness, reciprocal food sharing should occur among close kin. Why then do females with kin roost-mates help non-kin? We tested the hypothesis that helping non-kin increases a bat's success at obtaining future donations by expanding its network of potential donors. On six occasions, we individually fasted 14 adult females and measured donations from 28 possible donors. Each female was fasted before, during and after a treatment period, when we prevented donations from past donors (including 10 close relatives) by simultaneously fasting or removing them. This experiment was designed to detect partner switching and yielded three main results. First, females received less food when we prevented donations from a past donor versus a control bat. Donors within a group are therefore not interchangeable. Second, the treatment increased the variance in donors' contributions to food received by subjects, suggesting the possibility of alternative responses to a partner's inability to reciprocate. Finally, bats that fed more non-kin in previous years had more donors and received more food during the treatment. These results indicate that a bat can expand its network of possible donors by helping non-kin.

scholarly journals Social bet-hedging in vampire bats

2017 ◽  
Vol 13 (5) ◽  
pp. 20170112 ◽  
Author(s):  
Gerald G. Carter ◽  
Damien R. Farine ◽  
Gerald S. Wilkinson
Keyword(s):  
Social Network ◽  
Food Sharing ◽  
Support Network ◽  
Social Environments ◽  
Bet Hedging ◽  
Hedging Strategies ◽  
Social Network Structure ◽  
Vampire Bats ◽  
Indirect Fitness ◽  
Reduce Risk

Helping kin or nonkin can provide direct fitness benefits, but helping kin also benefits indirect fitness. Why then should organisms invest in cooperative partnerships with nonkin, if kin relationships are available and more beneficial? One explanation is that a kin-limited support network is too small and risky. Even if additional weaker partnerships reduce immediate net cooperative returns, individuals extending cooperation to nonkin can maintain a larger social network which reduces the potential costs associated with losing a primary cooperation partner. Just as financial or evolutionary bet-hedging strategies can reduce risk, investing in quantity of social relationships at the expense of relationship quality (‘social bet-hedging’) can reduce the risks posed by unpredictable social environments. Here, we provide evidence for social bet-hedging in food-sharing vampire bats. When we experimentally removed a key food-sharing partner, females that previously fed a greater number of unrelated females suffered a smaller reduction in food received. Females that invested in more nonkin bonds did not do better under normal conditions, but they coped better with partner loss. Hence, loss of a key partner revealed the importance of weaker nonkin bonds. Social bet-hedging can have important implications for social network structure by influencing how individuals form relationships.

scholarly journals Nice to kin and nasty to non-kin: revisiting Hamilton's early insights on eusociality

2013 ◽  
Vol 9 (6) ◽  
pp. 20130444 ◽  
Author(s):  
Jacobus J. Boomsma ◽  
Patrizia d'Ettorre
Keyword(s):  
Large Scale ◽  
Lower Proportion ◽  
Eusocial Insects ◽  
Large Scale Testing ◽  
Colony Odour ◽  
Social Animals ◽  
Helping Behaviour ◽  
Indirect Fitness ◽  
Fitness Benefits ◽  
Worker Sterility

When helping behaviour is costly, Hamiltonian logic implies that animals need to direct helpful acts towards kin, so that indirect fitness benefits justify the costs. We revisit inferences about nepotism and aggression in Hamilton's 1964 paper to argue that he overestimated the general significance of nepotism, but that other issues that he raised continue to suggest novel research agendas today. We now know that nepotism in eusocial insects is rare, because variation in genetic recognition cues is insufficient. A lower proportion of individuals breeding and larger clutch sizes selecting for a more uniform colony odour may explain this. Irreversible worker sterility can induce both the fiercest possible aggression and the highest likelihood of helping random distant kin, but these Hamiltonian contentions still await large-scale testing in social animals.

scholarly journals Kin selection, not indirect reciprocity, explains helping those who help others in ‘image scoring’

2019 ◽  
Author(s):  
Gilbert Roberts
Keyword(s):  
Kin Selection ◽  
Scoring Systems ◽  
Indirect Reciprocity ◽  
Helping Others ◽  
Helping Behaviour ◽  
Evolutionary Simulation ◽  
Indirect Fitness ◽  
The Individual ◽  
To Receive

AbstractIndirect reciprocity is often considered key to human sociality. It occurs when helping others results in an increase in reciprocal benefits from third parties. Indirect reciprocity has been proposed to operate through ‘image scoring’ mechanisms, whereby those who have been seen to help are more likely to receive help. Here I show that helping those who help others in image scoring models is not a mechanism of indirect reciprocity but is instead due to kin selection. Image scoring strategies are not individually adaptive because they base the decision to help upon whether a recipient has previously helped others, rather than upon whether helping would maximize their own return. Using analysis supported by evolutionary simulation, I show that helping can be favoured in image scoring systems without reciprocation, hence image scoring systems are not models of indirect reciprocity at all. Further, I use simulation of image scoring in meta-population models to illustrate how helping is a function of relatedness. I show that relatedness explains cooperation in image scoring (and associated) systems because helpers get indirect fitness benefits from helping others that share their strategy. A strategy of helping those who help others helps other copies of itself. In this way, helping behaviour ceases to be costly, and is in fact beneficial to the strategy, though not to the individual. Thus, despite some recent doubts about the usefulness of Hamilton’s rule, image scoring systems demonstrate the role of relatedness in driving cooperation.

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