scholarly journals Testing predictions of inclusive fitness theory in inbreeding relatives with biparental care

2019 ◽  
Vol 286 (1916) ◽  
pp. 20191933 ◽  
Author(s):  
Elizabeth A. Gow ◽  
Peter Arcese ◽  
Danielle Dagenais ◽  
Rebecca J. Sardell ◽  
Scott Wilson ◽  
...  
Keyword(s):  
Parental Care ◽  
Mating System ◽  
Feeding Rate ◽  
Inclusive Fitness ◽  
Empirical Studies ◽  
Feeding Rates ◽  
Extra Pair Paternity ◽  
Inclusive Fitness Theory ◽  
Parental Feeding ◽  
Focal Male

Inclusive fitness theory predicts that parental care will vary with relatedness between potentially caring parents and offspring, potentially shaping mating system evolution. Systems with extra-pair paternity (EPP), and hence variable parent–brood relatedness, provide valuable opportunities to test this prediction. However, existing theoretical and empirical studies assume that a focal male is either an offspring's father with no inbreeding, or is completely unrelated. We highlight that this simple dichotomy does not hold given reproductive interactions among relatives, complicating the effect of EPP on parent–brood relatedness yet providing new opportunities to test inclusive fitness theory. Accordingly, we tested hierarchical hypotheses relating parental feeding rate to parent–brood relatedness, parent kinship and inbreeding, using song sparrows ( Melospiza melodia ) experiencing natural variation in relatedness. As predicted, male and female feeding rates increased with relatedness to a dependent brood, even controlling for brood size. Male feeding rate tended to decrease as paternity loss increased, and increased with increasing kinship and hence inbreeding between socially paired mates. We thereby demonstrate that variation in a key component of parental care concurs with subtle predictions from inclusive fitness theory. We additionally highlight that such effects can depend on the underlying social mating system, potentially generating status-specific costs of extra-pair reproduction.

scholarly journals Helping in cooperatively breeding long-tailed tits: a test of Hamilton's rule

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130565 ◽  
Author(s):  
Ben J. Hatchwell ◽  
Philippa R. Gullett ◽  
Mark J. Adams
Keyword(s):  
Social Evolution ◽  
Inclusive Fitness ◽  
Empirical Studies ◽  
Alloparental Care ◽  
Hamilton’S Rule ◽  
Long Term Study ◽  
Inclusive Fitness Theory ◽  
Cooperatively Breeding ◽  
Helping Behaviour ◽  
Hamilton's Rule

Inclusive fitness theory provides the conceptual framework for our current understanding of social evolution, and empirical studies suggest that kin selection is a critical process in the evolution of animal sociality. A key prediction of inclusive fitness theory is that altruistic behaviour evolves when the costs incurred by an altruist ( c ) are outweighed by the benefit to the recipient ( b ), weighted by the relatedness of altruist to recipient ( r ), i.e. Hamilton's rule rb > c . Despite its central importance in social evolution theory, there have been relatively few empirical tests of Hamilton's rule, and hardly any among cooperatively breeding vertebrates, leading some authors to question its utility. Here, we use data from a long-term study of cooperatively breeding long-tailed tits Aegithalos caudatus to examine whether helping behaviour satisfies Hamilton's condition for the evolution of altruism. We show that helpers are altruistic because they incur survival costs through the provision of alloparental care for offspring. However, they also accrue substantial benefits through increased survival of related breeders and offspring, and despite the low average relatedness of helpers to recipients, these benefits of helping outweigh the costs incurred. We conclude that Hamilton's rule for the evolution of altruistic helping behaviour is satisfied in this species.

Intersexual variation and factors affecting parental care in Western Bluebirds: a comparison of nestling and fledgling periods

1990 ◽  
Vol 68 (4) ◽  
pp. 733-742 ◽  
Author(s):  
Kimberly A. With ◽  
Russell P. Balda
Keyword(s):  
Parental Care ◽  
Close Association ◽  
Feeding Rates ◽  
Energetic Costs ◽  
Factors Affecting ◽  
Brooding Period ◽  
Parental Feeding ◽  
Nestling Period ◽  
Brood Division ◽  
Western Bluebirds

We compared factors affecting parental feeding rates in Western Bluebirds (Sialia mexicana) between the nestling and fledgling periods to evaluate intersexual variation in parental care. Parents did not adjust the frequency of feeding visits between modal (five young) and below-modal (four or less young) broods during the nestling period. The frequency of parental feeding visits also was not significantly affected by offspring age during the nestling period. Males and females exhibited no significant differences in provisioning offspring, although males maintained a constant level of care throughout the nestling period, whereas females increased feeding visits following the brooding period. During the fledgling period, offspring from below-modal broods were fed at higher rates with increasing age than offspring from modal broods. Broods remained together (siblings averaged 8 m apart) within 200 m of the nest box for a week after fledging. As fledglings became more mobile, they would pursue parents while parents were foraging; parental feeding rates thus tended to increase with fledgling age and distance moved from the nest. Offspring sex did not influence parental care during the fledgling period. Both adults fed fledglings, with males taking sole care of fledglings if females initiated a second clutch soon (7–10 days) after fledging of the first brood. Parental feeding rates increased by 60% during the fledgling period compared with the nestling period. No evidence for brood division during the fledgling period was found. Although brood division represents one way of reducing energetic costs attributable to feeding fledglings, Western Bluebirds exhibit an alternate behavior in which the energetics of raising a brood are shared equally between the parents throughout both the nestling and fledgling periods. This is further facilitated by a close association of young during the fledgling period that may reduce energetic costs related to locating and feeding young.

Fledgling care and male parental effort in the Hooded Warbler (Wilsonia citrina)

1997 ◽  
Vol 75 (4) ◽  
pp. 576-581 ◽  
Author(s):  
Lesley J. Evans Ogden ◽  
Bridget J. M. Stutchbury
Keyword(s):  
Parental Care ◽  
Parental Effort ◽  
Feeding Rates ◽  
Male And Female ◽  
Wilsonia Citrina ◽  
Parental Feeding ◽  
Nestling Period ◽  
Brood Division ◽  
Hooded Warblers ◽  
Care Period

We followed family groups of Hooded Warblers (Wilsonia citrina) from hatching through to fledgling independence to determine (i) the duration and extent of parental care of fledglings, (ii) the extent of brood division, and (iii) whether male parental effort in caring for nestlings predicts male effort in caring for fledglings. The 9-day nestling period of Hooded Warblers was followed by 4 – 6 weeks of further parental care of fledged young. Parental feeding rates increased from hatching to when the young fledged from the nest, and males fed nestlings significantly more than females did. At the fledgling stage feeding rates to fledglings were significantly higher than at the nestling stage, but there was no difference in feeding rates between the parents. Parents usually divided the brood of fledglings equally, so that each parent assumed full and exclusive care of a subset of the brood. However, many females (45%) initiated a second brood and the male assumed care of the entire first brood at the time when his mate began incubating. The proportion of feeding trips to nestlings made by the male was not predictive of his subsequent effort in the care of fledglings. Exclusion of the fledgling care period in studies of parental investment may give a biased picture of overall investment on the part of both male and female parents.

scholarly journals Parent–offspring conflict and motivational control of brooding in an amphipod (Crustacea)

2006 ◽  
Vol 2 (4) ◽  
pp. 501-504 ◽  
Author(s):  
Jaimie T.A Dick ◽  
Robert W Elwood
Keyword(s):  
Parental Care ◽  
Late Stage ◽  
Empirical Studies ◽  
Honest Signalling ◽  
Inappropriate Use ◽  
Crangonyx Pseudogracilis ◽  
Parental Feeding ◽  
Partial Embryo ◽  
Early Late ◽  
Motivational Control

Models of parent–offspring conflict concerning levels of caregiving centre on conflict resolution by offspring control, compromise or offspring ‘honest signalling’ that parents use to maximize their own fitness. Recent empirical studies on motivational control of parental feeding of offspring are interpreted as supporting the latter model. Here, we examine parental care in an amphipod, Crangonyx pseudogracilis , which directs care to embryos in a brood pouch. Embryo removal and transplantation elucidated causal factors that determine levels of caregiving. In the short-term, females with all embryos removed reduced care activities, but partial embryo removal did not affect caregiving, evidence of ‘unshared’ parental care. In the long-term, females with all embryos removed ceased care. Thus, females have a maternal state that is maintained by stimuli from offspring. Transplantation of early/late stage embryos among females originally carrying early/late stage embryos revealed that stimuli from embryos indicate their age-dependent needs, but only modify caregiving within the constraints of a changing endogenous maternal state. Thus, we demonstrate that mothers and offspring share motivational control of care. However, we highlight the inappropriate use of motivational data in reaching conclusions about the resolution of parent–offspring conflict.

Social Evolution, Hamilton’s Rule, and Inclusive Fitness

2018 ◽  
Author(s):  
Samir Okasha
Keyword(s):  
Social Behaviour ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Popular Approach ◽  
Hamilton’S Rule ◽  
Inclusive Fitness Theory ◽  
The Social ◽  
Social Encounters ◽  
The Individual ◽  
Hamilton's Rule

Inclusive fitness theory, originally due to W. D. Hamilton, is a popular approach to the study of social evolution, but shrouded in controversy. The theory contains two distinct aspects: Hamilton’s rule (rB > C); and the idea that individuals will behave as if trying to maximize their inclusive fitness in social encounters. These two aspects of the theory are logically separable but often run together. A generalized version of Hamilton’s rule can be formulated that is always true, though whether it is causally meaningful is debatable. However, the individual maximization claim only holds true if the payoffs from the social encounter are additive. The notion that inclusive fitness is the ‘goal’ of individuals’ social behaviour is less robust than some of its advocates acknowledge.

scholarly journals Inclusive Fitness Theory from Darwin to Hamilton

Genetics ◽  
2007 ◽  
Vol 176 (3) ◽  
pp. 1375-1380
Author(s):  
Lee Alan Dugatkin
Keyword(s):  
Inclusive Fitness ◽  
Inclusive Fitness Theory

scholarly journals War and peace: social interactions in infections

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130365 ◽  
Author(s):  
Helen C. Leggett ◽  
Sam P. Brown ◽  
Sarah E. Reece
Keyword(s):  
Species Interactions ◽  
Disease Ecology ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Experimental Tests ◽  
Microbial Pathogens ◽  
Emergent Properties ◽  
Social Strategies ◽  
Inclusive Fitness Theory ◽  
Social Behaviours

One of the most striking facts about parasites and microbial pathogens that has emerged in the fields of social evolution and disease ecology in the past few decades is that these simple organisms have complex social lives, indulging in a variety of cooperative, communicative and coordinated behaviours. These organisms have provided elegant experimental tests of the importance of relatedness, kin discrimination, cooperation and competition, in driving the evolution of social strategies. Here, we briefly review the social behaviours of parasites and microbial pathogens, including their contributions to virulence, and outline how inclusive fitness theory has helped to explain their evolution. We then take a mechanistically inspired ‘bottom-up’ approach, discussing how key aspects of the ways in which parasites and pathogens exploit hosts, namely public goods, mobile elements, phenotypic plasticity, spatial structure and multi-species interactions, contribute to the emergent properties of virulence and transmission. We argue that unravelling the complexities of within-host ecology is interesting in its own right, and also needs to be better incorporated into theoretical evolution studies if social behaviours are to be understood and used to control the spread and severity of infectious diseases.

scholarly journals Sexual selection favours male parental care, when females can choose

2011 ◽  
Vol 279 (1734) ◽  
pp. 1784-1790 ◽  
Author(s):  
Suzanne H. Alonzo
Keyword(s):  
Sexual Selection ◽  
Parental Care ◽  
Female Choice ◽  
Mating Success ◽  
Current Theory ◽  
Sharp Contrast ◽  
Recent Theory ◽  
Extra Pair Paternity ◽  
Female Promiscuity ◽  
Male Care

Explaining the evolution of male care has proved difficult. Recent theory predicts that female promiscuity and sexual selection on males inherently disfavour male care. In sharp contrast to these expectations, male-only care is often found in species with high extra-pair paternity and striking variation in mating success, where current theory predicts female-only care. Using a model that examines the coevolution of male care, female care and female choice; I show that inter-sexual selection can drive the evolution of male care when females are able to bias mating or paternity towards parental males. Surprisingly, female choice for parental males allows male care to evolve despite low relatedness between the male and the offspring in his care. These results imply that predicting how sexual selection affects parental care evolution will require further understanding of why females, in many species, either do not prefer or cannot favour males that provide care.

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.

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