Sexual conflicts in spotted hyenas: male and female mating tactics and their reproductive outcome with respect to age, social status and tenure

Abstract

We investigated the reproductive outcomes of male and female mating tactics in the spotted hyena, Crocuta crocuta, a female-dominated social carnivore with high maternal investment, an absence of paternal care and female control over copulation. Paternity was determined using microsatellite profiling of 236 offspring in 171 litters from three clans. We found little evidence that male tactics that sought to coerce or monopolize females were successful. Polyandry and sperm competition appeared to counter effectively pre-copulatory male tactics, such as harassment, monopolization and other tactics, such as infanticide, that were against the evolutionary interests of females, and may have contributed to the stability of the male dominance hierarchy, which operated as a social queue. At least 39% of 54 females mated multiply, and 35% of 75 twin litters were fathered by two sires. Polyandry may also serve to ensure fertilization, compensate for an initial poor-quality mate or ensure fertilization by genetically compatible mates. Female mate choice matched observed patterns of affiliative male-female behaviour, indicating that affiliative behaviour is a successful male mating tactic, and was consistent with the idea that male tenure may serve as an index of male quality, although male fertility may decline with extreme old age.

Courtship and mating in free-living spotted hyenas

“…Like East et al (2003) we found no evidence that mate-guarding or consortship (what they called 'shadowing') strongly influenced female mate preference. That we sometimes saw a female mating with different males on consecutive days, but never observed any one mating pair copulating repeatedly on successive days, suggests that mate-guarding is not necessarily a successful male strategy.…”

“…Both observations of mating and paternity tests based on microsatellite data confirm that high-ranking males do not monopolize reproduction in this species, as they do in many other polygynous mammals (e.g., Clutton-Brock, 1988;Altmann et al, 1996). Modal litter size in Crocuta is two (Holekamp et al, 1996), and 20-40% of twin litters are sired by multiple males (Engh et al, 2002;East et al, 2003).…”

“…As do many felids (e.g., Caro & Collins, 1987), spotted hyenas mate promiscuously, and no enduring pair bond develops between the sexes (Szykman et al, 2001;Engh et al, 2002;East et al, 2003). Females have been observed mating with up to three males during a single estrous period, and members of both sexes have been known to copulate with several different mates over the course of several years (Engh et al, 2002).…”

The lemur syndrome unresolved: extreme male reproductive skew in sifakas (Propithecus verreauxi), a sexually monomorphic primate with female dominance

“…Hence, neither males nor females seem to enjoy benefits of group augmentation in terms of improved survival, even though such benefits are expected to be greatest at such small group sizes (Hamilton 1971). Thus, despite their ability to dominate males, female sifakas do not appear to influence group composition and the distribution of paternity to the extent observed in other mammals with powerful females (East et al 2003), but there may be interesting intraspecific variation in these costs and benefits because a recent study at Beza Mahafaly documented that the majority (29 of 52) of males there sired at least one offspring outside their resident group (Lawler 2007).…”

“…Female breeding success may be strongly affected by behavioral and morphological traits in cooperative or eusocial mammals with high female reproductive skew, such as meerkats or naked mole-rats, and also in other species with larger and more aggressive females, such as spotted hyenas or many lemurs (see, e.g., Vick and Pereira 1989;East et al 2003). As a result, sex differences in morphology and behavior may deviate from classical predictions of sexual selection theory and affect intersexual relations and the operation of sexual selection in unpredicted ways .…”