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 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.

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 Non-reciprocal but peaceful fruit sharing in wild bonobos in Wamba

Behaviour ◽  
2015 ◽  
Vol 152 (3-4) ◽  
pp. 335-357 ◽  
Author(s):  
Shinya Yamamoto
Keyword(s):  
Driving Force ◽  
Social Bonds ◽  
Food Sharing ◽  
Evolution Of Cooperation ◽  
Reciprocal Exchange ◽  
Adult Females ◽  
Different Characteristics ◽  
Meat Sharing

Food sharing is considered to be a driving force in the evolution of cooperation in human societies. Previously postulated hypotheses for the mechanism and evolution of food sharing, e.g., reciprocity and sharing-under-pressure, were primarily proposed on the basis of meat sharing in chimpanzees. However, food sharing in bonobos has some remarkably different characteristics. Here I report details pertaining to fruit sharing in wild bonobos in Wamba based on 150 events of junglesop fruit sharing between independent individuals. The bonobos, primarily adult females, shared fruit that could be obtained individually without any cooperation or specialized skills. There was no evidence for reciprocal exchange, and their peaceful sharing seems to contradict the sharing-under-pressure explanation. Subordinate females begged for abundant fruit from dominants; this might indicate that they tested the dominants’ tolerance based on social bonds rather than simply begging for the food itself, suggesting existence of courtesy food sharing in bonobos.

scholarly journals OPPOSITION TO INBREEDING AMONG CLOSE KIN

2018 ◽  
Author(s):  
Jan Antfolk ◽  
Debra Lieberman ◽  
Christopher Harju ◽  
Anna Albrecht ◽  
Andreas Mokros ◽  
...  
Keyword(s):  
Inclusive Fitness ◽  
Large Population ◽  
Self Regulation ◽  
Family Members ◽  
Indirect Costs ◽  
Population Based ◽  
Fitness Costs ◽  
Inclusive Fitness Theory ◽  
The Difference ◽  
Close Relatives

Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene’s-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive-fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6% of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation.

scholarly journals Social foraging in vampire bats is predicted by long-term cooperative relationships

2021 ◽  
Author(s):  
Simon P. Ripperger ◽  
Gerald G. Carter
Keyword(s):  
Social Evolution ◽  
Group Living ◽  
Food Sharing ◽  
Social Foraging ◽  
Social Grooming ◽  
Cooperative Relationships ◽  
Vampire Bats ◽  
In Captivity ◽  
Access To Food

AbstractStable social bonds in group-living animals can provide greater access to food. A striking example is that female vampire bats often regurgitate blood to socially bonded kin and nonkin that failed in their nightly hunt. Food-sharing relationships form via preferred associations and social grooming within roosts. However, it remains unclear whether these cooperative relationships extend beyond the roost. To evaluate if long-term cooperative relationships in vampire bats play a role in foraging, we tested if foraging encounters measured by proximity sensors could be explained by wild roosting proximity, kinship, or rates of co-feeding, social grooming, and food sharing during 22 months in captivity. We assessed evidence for six hypothetical scenarios of social foraging, ranging from individual to collective hunting. We found that female vampire bats departed their roost individually, but often re-united far outside the roost. Nonrandomly repeating foraging encounters were predicted by within-roost association and histories of cooperation in captivity, even when controlling for kinship. Foraging bats demonstrated both affiliative and competitive interactions and a previously undescribed call type. We suggest that social foraging could have implications for social evolution if ‘local’ cooperation within the roost and ‘global’ competition outside the roost enhances fitness interdependence between frequent roostmates.

scholarly journals Development of New Food-Sharing Relationships in Vampire Bats

2020 ◽  
Vol 30 (7) ◽  
pp. 1275-1279.e3 ◽  
Author(s):  
Gerald G. Carter ◽  
Damien R. Farine ◽  
Rachel J. Crisp ◽  
Julia K. Vrtilek ◽  
Simon P. Ripperger ◽  
...  
Keyword(s):  
Food Sharing ◽  
Vampire Bats

scholarly journals Males harm females less when competing with familiar relatives

2017 ◽  
Vol 284 (1867) ◽  
pp. 20171984 ◽  
Author(s):  
Samuel J. Lymbery ◽  
Leigh W. Simmons
Keyword(s):  
Egg Production ◽  
Callosobruchus Maculatus ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Fitness Costs ◽  
Offspring Production ◽  
Social Familiarity ◽  
Indirect Fitness ◽  
Opposite Sex ◽  
Female Lifespan

Sexual conflict occurs when reproductive partners have different fitness optima, and can lead to the evolution of traits in one sex that inflict fitness costs on the opposite sex. Recently, it has been proposed that antagonism by males towards females should be reduced when they compete with relatives, because reducing the future productivity of a female would result in an indirect fitness cost for a harmful male. We tested this prediction in the seed beetle Callosobruchus maculatus , the males of which harm females with genital spines and pre-copulatory harassment. We compared lifespan, lifetime egg production and lifetime offspring production among females housed with groups of males that varied in their familiarity and relatedness. Females produced significantly more eggs and offspring when grouped with males who were both related and familiar to each other. There was no effect of male relatedness or familiarity on female lifespan. Our results suggest that males plastically adjust their harmfulness towards females in response to changes in inclusive fitness payoffs, and that in this species both genetic relatedness and social familiarity mediate this effect.

scholarly journals Male relatedness and familiarity are required to modulate male-induced harm to females in Drosophila

2017 ◽  
Vol 284 (1860) ◽  
pp. 20170441 ◽  
Author(s):  
Sally Le Page ◽  
Irem Sepil ◽  
Ewan Flintham ◽  
Tommaso Pizzari ◽  
Pau Carazo ◽  
...  
Keyword(s):  
Potential Role ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Kin Recognition ◽  
Female Reproduction ◽  
Fitness Effects ◽  
Inclusive Fitness Theory ◽  
Indirect Fitness ◽  
Female Lifespan

Males compete over mating and fertilization, and often harm females in the process. Inclusive fitness theory predicts that increasing relatedness within groups of males may relax competition and discourage male harm of females as males gain indirect benefits. Recent studies in Drosophila melanogaster are consistent with these predictions, and have found that within-group male relatedness increases female fitness, though others have found no effects. Importantly, these studies did not fully disentangle male genetic relatedness from larval familiarity, so the extent to which modulation of harm to females is explained by male familiarity remains unclear. Here we performed a fully factorial design, isolating the effects of male relatedness and larval familiarity on female harm. While we found no differences in male courtship or aggression, there was a significant interaction between male genetic relatedness and familiarity on female reproduction and survival. Relatedness among males increased female lifespan, reproductive lifespan and overall reproductive success, but only when males were familiar. By showing that both male relatedness and larval familiarity are required to modulate female harm, these findings reconcile previous studies, shedding light on the potential role of indirect fitness effects on sexual conflict and the mechanisms underpinning kin recognition in fly populations.

Four new species of mealybug (Pseudococcidae) and a new species of soft scale (Coccidae: Coccoidea: Hemiptera) from Greenland and redescriptions of a mealybug and a soft scale from Arctic Canada

Zootaxa ◽  
2005 ◽  
Vol 897 (1) ◽  
pp. 1
Author(s):  
Carl-Axel Gertsson ◽  
Chris Hodgson
Keyword(s):  
New Species ◽  
Arctic Canada ◽  
Soft Scale ◽  
Adult Females ◽  
Close Relatives ◽  
A New Species

The adult females of four new mealybug species are described from Greenland (Atrococcus groenlandensis, Chorizococcus multiporus and Trionymus bocheri and T. elymus) and a key is provided for all mealybug species known from Greenland; a new species of Coccidae is also described from Greenland (Pulvinaria glacialis). In addition, the adult females of the mealybug Atrococcus altoarcticus Richards and the soft scale Pulvinaria ellesmerensis Richards from arctic Canada are redescribed and compared with their close relatives from Greenland.

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