Cycles, sexuality, and conception in free‐ranging langurs (<i>Presbytis entellus</i>)

Sommer, Volker; Srivastava, Arun; Borries, Carola

doi:10.1002/ajp.1350280102

Cited by 99 publications

(105 citation statements)

References 38 publications

(7 reference statements)

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“…Here, we demonstrate that the method is useful not only for characterizing ovarian cycles but also for providing more precise information on the timing of ovulation. An overall cycle length of 26^27 days comprising a follicular phase of 13 days and a luteal phase of 13^14 days in our study females agrees with ¢gures derived from hormonal studies on captive animals (Lohiya et al 1988;Heistermann et al 1995) and is in line with ¢eld data on inter-oestrus intervals previously reported for this ) and other (Sommer et al 1992) populations of the species.…”

Section: Discussionsupporting

confidence: 92%

“…As predicted, and in line with the paternity-confusion hypothesis, these periods were markedly variable in length (range 4^15 days) and, with an average duration of 9^10 days (cf. Borries et al 2001), were also signi¢cantly longer than in females living in one-male groups at Jodphur (4 days; Sommer et al 1992) in which paternity confusion is less of an option. Furthermore, females in our study group showed a substantial overlap in receptive phases, with as many as six females being receptive at the same time.…”

Section: Discussionmentioning

confidence: 88%

“…Receptive periods were de¢ned as periods during which females were engaged in proceptive and/or receptive behaviours, i.e. sexual solicitations directed to males, copulation attempts and/or copulations (Sommer et al 1992). A receptive period was classi¢ed as such if the sexual behaviours mentioned above were shown for a minimum of 3 consecutive days and, if lasting longer, were without interruptions of more than 2 days.…”

Section: (B) Behavioural Observationsmentioning

confidence: 99%

“…The species shows a high £exibility in social organization, forming multi-female groups that can contain both single and multiple males (Sommer et al 1992;Borries 1997). In multi-male groups females usually mate with all males during an extended period of receptivity (Borries et al 1999a(Borries et al ,b, 2001.…”

Section: Introductionmentioning

confidence: 99%

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Loss of oestrus, concealed ovulation and paternity confusion in free-ranging Hanuman langurs

Hestermann

Ziegler

Schaik

et al. 2001

Proc. R. Soc. Lond. B

120

100

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Ovarian cycles in catarrhine primates are uniquely characterized by prolonged periods of sexual activity in which the timings of ovulation and copulation do not necessarily correspond. According to current hypotheses of primate social evolution, extended sexuality in multi-male groups might represent part of a female strategy to confuse paternity in order to reduce the risk of infanticide by males. We test this hypothesis by examining mating behaviour in relation to timing of ovulation and paternity outcome in a multi-male group of free-living Hanuman langurs. Using faecal progestogen measurements, we ¢rst document that female langurs have extended receptive periods in which the timing of ovulation is highly variable. Next, we demonstrate the capacity for paternity confusion by showing that ovulation is concealed from males and that copulations progressively decline throughout the receptive phase. Finally, we demonstrate multiple paternity, and show that despite a high degree of monopolization of receptive females by the dominant male, non-dominant males father a substantial proportion of o¡spring. We believe that this is the ¢rst direct evidence that extended periods of sexual activity in catarrhine primates may have evolved as a female strategy to confuse paternity.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 88%

Section: (B) Behavioural Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Loss of oestrus, concealed ovulation and paternity confusion in free-ranging Hanuman langurs

Hestermann

Ziegler

Schaik

et al. 2001

Proc. R. Soc. Lond. B

120

100

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“…Jodhpur females appear to alter their reproductive parameters in three ways (Sommer et al 1992). Firstly, menstruations as a sign of impending fertility are clearly visible to human observers in 89% of all cycles, lasting for an average of 1.9 days (range 1-6 days)-as opposed to being invisible in the multi-male society of Ramnagar.…”

Section: Adjusting Sexual Signals: the Case Of Langur Monkeysmentioning

confidence: 99%

Untitled

2013

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Reproductive synchrony or desynchrony of primate females influences number and fitness of males in mating systems. Langur monkey populations provide a natural experiment for observing alternative female strategies of confusing or concentrating paternity. Where females escape seasonal reproductive constraints, they desynchronize fertility and show visible cues (menstruation), enabling single males to monopolize matings. This increases female fitness by reducing food competition. Where langurs are seasonally constrained, females conceal fertility, confusing paternity and reducing infanticide. These case studies illuminate how hominin females could increase male numbers and investment. Fitness payoffs to male investors will be affected by degree of reproductive seasonal constraint, and by females either concealing or confusing menstrual cues of imminent fertility. Among ancestors of modern humans and Neanderthals these strategies diverged. Under pressure of encephalization, modern human female ancestors, less seasonally constrained, pursued a strategy of cosmeticization of menstrual signals. This Female Cosmetic Coalitions model accounts for the African Middle Stone Age record of pigment use. Among Neanderthals, strategies alternated. Severe seasonality during glacial cycles tied Neanderthal males into pair-bonds, suppressing cosmetic signaling. Only during interglacials when seasonality relaxed would Neanderthal females require blood-red cosmetics. Our Seasonality Thermostat model explains why European ochre use correlates with climate through the Middle to Late Pleistocene. INTRODUCTION There is a growing consensus that evolving Homo mothers relied on cooperative breeding to raise larger-bodied, larger-brained offspring (e.g., Aiello and Key 2002;Barrickman et al. 2008;Burkart et al. 2009;Robson and Wood 2008;Shultz et al. 2012;van Schaik et al. 2006 Models for cultural levels of human cooperation (Boyd and Richerson 1992, 2005Gintis et al. 2003;Henrich and Boyd 2001;Henrich et al. 2003Henrich et al. , 2006Nowak and Sigmund 2005;Richerson et al. 2003), invoke multilevel and group selection processes, but ignore what is most difficult to explain-how to secure cooperation between the sexes, given the trade-off between investing in current offspring versus future mating opportunities (cf. Bowles 2006). One game theory model (Key 1998(Key , 2000 incorporated the differences of reproductive energetic costs to specify conditions for the evolution of cooperation that can be practically applied to the fossil record. Yet even these conditions do not identify how females induced males to subsidize their reproduction (Kaplan et al. 2000;Marlowe 2001). Recent models (Gavrilets 2012) highlight the difficulty of shifting from systems of significant male mating competition into productive male investment, where males face a social dilemma of ceding fitness advantage to free-riding rivals.If we can define the mechanisms available to Homo females giving them leverage against male defection through the Early to Middle Plei...

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Dental eruption sequence among colobine primates

Harvati¹

2000

Am. J. Phys. Anthropol.

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Dental development is one aspect of growth that is linked to diet and to life history but has not been investigated among colobines since the work of Schultz [1935]. This study establishes the dental eruption sequence for several colobine species and compares it to that of other catarrhines. The mandibles and maxillae of two hundred and four juvenile colobine specimens were scored for presence or absence of permanent teeth and for stages of partial eruption. Eruption was defined as ranging between tooth emergence (any part of a tooth crown above the alveolar margin) and full occlusion, with three intermediate levels manifest between these boundaries. In African colobines, represented by C. guereza, C. angolensis and P. badius, M2 erupts before I2, and in C. angolensis it also erupts before I1. The canine is delayed, erupting after the premolars in females and after M3 in males. Asian colobines show greater diversity in eruption sequences. Nasalis shows no early eruption of the molars and is very similar to Macaca. In Trachypithecus and Pygathrix M(2) erupts before I(2). The canine in Trachypithecus is delayed, erupting after the premolars and, in some males, after M3. In Presbytis M2 erupts before both incisors; M3 erupts before C in both sexes, and often before both premolars. Although the actual timing of eruption is unknown, all colobine species examined except N. larvatus showed some degree of relatively early eruption of M2 and M3. The lack of this tendency in Nasalis sets this genus apart from all other colobines represented in this study. Dental eruption sequence is thought to reflect life history patterns. Early molar eruption in colobines was thought by Schultz (1935) to be a primitive character reflecting shorter life history. Faster growth rates found in folivorous primates have been interpreted as being related to an adaptation to folivory (Leigh 1994), and early eruption of molars may be part of this dietary specialization. The relationships between dental development and both diet and life history are investigated.

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Cycles, sexuality, and conception in free‐ranging langurs (Presbytis entellus)

Cited by 99 publications

References 38 publications

Loss of oestrus, concealed ovulation and paternity confusion in free-ranging Hanuman langurs

Loss of oestrus, concealed ovulation and paternity confusion in free-ranging Hanuman langurs

Untitled

Dental eruption sequence among colobine primates

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