Classic life-history theory predicts that menopause should not occur because there be no selection for survival after the cessation of reproduction [1Williams G.C. Pleiotropy, natural selection, and evolution senescence.Evolution. 1957; 11: 398-411Crossref Google Scholar]. Yet, human females routinely live 30 years they have stopped reproducing [2Hill K. Hurtado A.M. Social science: Human reproductive assistance.Nature. 2012; 483: 160-161Crossref PubMed Scopus (7) Only two other...

An enduring puzzle of human life history is why women cease reproduction midway through life. Selection can favor postreproductive survival because older females help their offspring to reproduce. But the kin-selected fitness gains helping appear insufficient outweigh potential benefits continued reproduction. Why then do in first place? Here, we suggest that early reproductive cessation humans outcome competition between generations, and present a simple candidate model how this will be...

Most recent models of the partitioning reproduction attempt to explain patterns skew on assumption that dominant individuals have complete control over breeding opportunities within group, but may nevertheless concede a share direct subordinates as an incentive remain peacefully in association. Although these be applicable some animal societies, we argue they fail provide comprehensive theory skew. Instead, suggest often able claim unsanctioned for themselves, will forced exercise degree...

Human females stop reproducing long before they die. Among other mammals, only pilot and killer whales exhibit a comparable period of post-reproductive life. The grandmother hypothesis suggests that kin selection can favour survival when older help their relatives to reproduce. But although there is an evidence grandmothers provide such assistance, it puzzling why menopause should have evolved among the great apes toothed whales. We previously suggested (Cant & Johnstone 2008 Proc. Natl...

Individual foraging specialisation has important ecological implications, but its causes in group-living species are unclear. One of the major consequences group living is increased intragroup competition for resources. Foraging theory predicts that with competition, individuals should add new prey items to their diet, widening niche ('optimal hypothesis'). However, classic suggests opposite: leads partitioning and greater individual ('niche We tested these opposing predictions wild, banded...

Why females of some species cease ovulation prior to the end their natural lifespan is a long-standing evolutionary puzzle [1-4]. The fitness benefits post-reproductive helping could in principle select for menopause [1, 2, 5], but magnitude these appears insufficient explain timing [6-8]. Recent theory suggests that cost inter-generational reproductive conflict between younger and older same social unit critical missing term classical inclusive calculations (the "reproductive hypothesis"...

An individual's ecological environment affects their mortality risk, which in turn has fundamental consequences for life-history evolution. In many species, social relationships are likely to be an important component of environment, and therefore risk. Here, we examine the relationship between position risk resident killer whales ( Orcinus orca ) using over three decades demographic data. We find that male, but not female, unit predicts More socially integrated males have a significantly...

Abstract A species has a post‐reproductive stage if, like humans, female entering the adult population can expect to live substantial proportion of their life after last reproductive event. However, it is conceptually and statistically challenging distinguish these true stages from usual processes senescence, which result in females occasionally surviving past Hence, despite considerable interest, taxonomic prevalence remains unclear debated. In this study we use tables constructed published...

Little attention has been paid to a conspicuous and universal feature of animal societies: the variation between individuals in helping effort. Here, we develop multiplayer kin–selection model that assumes subordinates face trade–off because current investment help reduces their own future reproductive success. The makes two predictions: (i) will work less hard closer they are inheriting breeding status; (ii) for given dominance rank, larger groups. second prediction reflects pay–off from...

Scent marking is commonly described as a territorial behaviour, and scent marks might deter potential intruders from entering occupied areas. Conspecific neighbours present both reproductive threat, thus, determining which, if any, of these threats shapes scent-marking behaviour difficult. Banded mongooses Mungos mungo provide rare clear separation between rivals (found within groups) (neighbouring groups), because immigration into social groups extremely rare, mating occurs almost...

In this article, we explore the impact of sex-biased dispersal on local relatedness and selection for helping harming behavior among males females. We show that in a patch-structured population, when there is marked sex bias dispersal, will almost always favor individuals more prone to dispersal. This result holds regardless effects mating skew or overlapping generations. Selection may well also philopatric sex, particularly if generational overlap, but less likely occur compete intensely...

Considerable research has focused on understanding variation in reproductive skew cooperative animal societies, but the pace of theoretical development far outstripped empirical testing models. One major class model suggests that dominant individuals can use threat eviction to deter subordinate reproduction (the ‘restraint’ model), this idea remains untested. Here, we long-term behavioural and genetic data test assumptions restraint banded mongooses ( Mungos mungo ), a species which...

In most species the reproductive system ages at same rate as somatic tissue and individuals continue reproducing until death. However, females of three - humans, killer whales short-finned pilot have been shown to display a markedly increased senescence relative ageing. these species, significant proportion live beyond their lifespan: they post-reproductive lifespan. Research into this puzzling life-history strategy is hindered by difficulties quantifying in wild populations. Here we present...

All animals are anatomically constrained in the number of discrete call types they can produce. Recent studies suggest that by combining existing calls into meaningful sequences, increase information content their vocal repertoire despite these constraints. Additionally, signalers use signatures or cues correlated to other individual traits contexts encoded vocalizations. However, encoding multiple using same components vocalizations usually reduces signals' reliability. Segregation could...

Conflict between groups is a notable feature of many animal societies. Recent theoretical models suggest that violent intergroup conflict can shape patterns within-group cooperation. However, despite its prevalence in social species, the adaptive significance has been little explored outside humans and chimpanzees, Pan troglodytes. A barrier to current understanding role evolution behaviour lack information on causes consequences aggression groups. Here, we examined fitness banded mongoose,...

Understanding why females of some mammalian species cease ovulation prior to the end life is a long-standing interdisciplinary and evolutionary challenge. In humans toothed whales, can live for decades after stopping reproduction. This unusual history trait thought have evolved, in part, due inclusive fitness benefits that postreproductive gain by helping kin. humans, grandmothers increasing their number surviving grandoffspring, referred as grandmother effect. Among effect has not been...