Alternative male reproductive strategies: male bimaturism in orangutans

Atmoko, Suci Utami; Hooff, Jan A. R. A. M. van

doi:10.1017/cbo9780511542459.013

Cited by 33 publications

(26 citation statements)

References 62 publications

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“…2). Females of P. pygmaeus prefer to copulate with territorial males that are very intolerant of one another whereas matings with non‐territorial males occur only sporadically (Singleton and van Schaik 2002; Atmoko and van Hooff 2004; Goossens et al 2006). Male–male competition on the postcopulatory level can thus be assumed to be lower in P. pygmaeus than in the promiscuous lemur M. murinus .…”

Section: Discussionmentioning

confidence: 99%

Sequence Evolution of the Sperm Ligand Zonadhesin Correlates Negatively With Body Weight Dimorphism in Primates

Herlyn

Zischler

2007

Evolution

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Sexual selection has repeatedly been shown to be the probable driving force behind the positive Darwinian evolution of genes affecting male reproductive success. Here we compare the sequence evolution of the sperm ligand zonadhesin with body mass dimorphism in primates. In contrast to previous related studies, the present approach takes into account not only catarrhine primates, but also platyrrhines and lemurs. In detail, we analyze the sequence evolution of concatenated zonadhesin fragments (555 bp) of four Lemuroidea, five Platyrrhini, and seven Catarrhini, using the rate ratio of nonsynonymous to synonymous substitutions (d n /d s = ). Unexpectedly, subsequent regression analyzes between estimates for the terminal branches of a primate phylogeny and residual male body mass reveal that sequence evolution of zonadhesin decreases with increasing sexual dimorphism in body weight. Mapping published mating system classifications onto these results illustrates that unimale breeding species show a tendency for rather slow sequence evolution of zonadhesin and comparably pronounced sexual dimorphism in body weight.Female choice and sperm competition can be assumed to drive the evolution of zonadhesin. We speculate that the level of sperm competition is lower in more sexually dimorphic primates because males of these species monopolize access to fertile females more successfully. Thus, variation in sperm competition may be driving the observed negative correlation of sequence evolution and sexual dimorphism in body weight.

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Section: Discussionmentioning

confidence: 99%

Sequence Evolution of the Sperm Ligand Zonadhesin Correlates Negatively With Body Weight Dimorphism in Primates

Herlyn

Zischler

2007

Evolution

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“…Orangutans exhibit a uniquely pronounced male bimaturism, which has been associated with alternative male reproductive strategies (MacKinnon 1974; Utami Atmoko and van Hooff 2004;Pradhan et al 2012;Dunkel et al 2013). Unflanged males, who lack secondary sexual characteristics, reportedly associate, copulate, and coerce copulations more frequently than flanged males in the majority of study populations (MacKinnon 1974;Galdikas 1985b;Sugardjito et al 1987;Knott 2009;Mitra Setia et al 2009;Utami Atmoko et al 2009;JAK et al, unpubl.…”

Section: Male Bimaturism and Sexual Conflictmentioning

confidence: 99%

The cost of associating with males for Bornean and Sumatran female orangutans: a hidden form of sexual conflict?

Kunz

Duvot

Noordwijk

et al. 2020

Behav Ecol Sociobiol

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Sexual coercion, in the form of forced copulations, is relatively frequently observed in orangutans and generally attributed to their semi-solitary lifestyle. High ecological costs of association for females may be responsible for this lifestyle and may have prevented the evolution of morphological fertility indicators (e.g., sexual swellings), which would attract (male) associates. Therefore, sexual conflict may arise not only about mating per se but also about associations, because males may benefit from associations with females to monitor their reproductive state and attempt to monopolize their sexual activities. Here, we evaluate association patterns and costs for females when associating with both males and females of two different orangutan species at two study sites: Suaq, Sumatra (Pongo abelii), and Tuanan, Borneo (Pongo pygmaeus wurmbii). Female association frequency with both males and females was higher in the Sumatran population, living in more productive habitat. Accordingly, we found that the cost of association, in terms of reduced feeding to moving ratio and increased time being active, is higher in the less sociable Bornean population. Males generally initiated and maintained such costly associations with females, and prolonged associations with males led to increased female fecal cortisol metabolite (FCM) levels at Tuanan, the Bornean population. We conclude that male-maintained associations are an expression of sexual conflict in orangutans, at least at Tuanan. For females, this cost of association may be responsible for the lack of sexual signaling, while needing to confuse paternity. Significance statement Socioecological theory predicts a trade-off between the benefits of sociality and the ecological costs of increased feeding competition. Orangutans’ semi-solitary lifestyle has been attributed to the combination of high association costs and low predation risk. Previous work revealed a positive correlation between association frequencies and habitat productivity, but did not measure the costs of association. In this comparative study, we show that females likely incur costs from involuntary, male-maintained associations, especially when they last for several days and particularly in the population characterized by lower association frequencies. Association maintenance therefore qualifies as another expression of sexual conflict in orangutans, and especially prolonged, male-maintained associations may qualify as an indirect form of sexual coercion.

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“…Unflanged males lack SSCs, but have fully developed testicles (Dahl et al, 1993), reproduce successfully in the wild (Goossens et al, 2006; Utami, 2002), and continue to grow in body size (Leigh & Shea, 1995). The duration of the unflanged stage appears to be highly variable (Dunkel et al, 2013), but detailed data from wild populations are still largely missing, because of orangutans’ slow life history (one study documents a wild individual remaining unflanged for 20 years before developing SSCs: Utami Atmoko & van Hooff, 2004). The final transition from the unflanged to the flanged male morph occurs within a few months and is accompanied by a peak in testosterone levels (captivity: Maggioncalda et al, 1999; wild: Marty et al, 2015; rehabilitation centers: Prasetyo, 2019).…”

Section: Introductionmentioning

confidence: 99%

Alternative reproductive tactics of unflanged and flanged male orangutans revisited

Kunz

Duvot

Ashbury

et al. 2023

American J Primatol

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In many slowly developing mammal species, males reach sexual maturity well before they develop secondary sexual characteristics. Sexually mature male orangutans have exceptionally long periods of developmental arrest. The two male morphs have been associated with behavioral alternative reproductive tactics, but this interpretation is based on cross‐sectional analyses predominantly of Northwest Sumatran populations. Here we present the first longitudinal analyses of behavioral changes of 10 adult males that have been observed in both unflanged and flanged morph. We also analyzed long‐term behavioral data on an additional 143 individually identified males from two study sites, Suaq (Sumatra, Pongo abelii) and Tuanan (Borneo, Pongo pygmaeus wurmbii), to assess male mating tactics cross‐sectionally in relation to population, male morph (unflanged and flanged), and other socio‐ecological factors. Both our longitudinal and cross‐sectional results confirm and refine previous cross‐sectional accounts of the differences in mating tactics between the unflanged and the flanged male morphs. In the unflanged morph, males exhibit higher sociability, particularly with females, and higher rates of both copulation and sexual coercion than in the flanged morph. Based on our results and those of previous studies showing that females prefer flanged males, and that flanged males have higher reproductive success, we conclude that unflanged males face a trade‐off between avoiding male‐male contest competition and gaining mating access to females, and thus follow a “best‐of‐a‐bad‐job” mating strategy.

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Alternative male reproductive strategies: male bimaturism in orangutans

Cited by 33 publications

References 62 publications

Sequence Evolution of the Sperm Ligand Zonadhesin Correlates Negatively With Body Weight Dimorphism in Primates

Sequence Evolution of the Sperm Ligand Zonadhesin Correlates Negatively With Body Weight Dimorphism in Primates

The cost of associating with males for Bornean and Sumatran female orangutans: a hidden form of sexual conflict?

Alternative reproductive tactics of unflanged and flanged male orangutans revisited

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