Evidence for sexually selected infanticide in captiveCercopithecus mitis,Cercocebus torquatus,andMandrillus leucophaeus

Adult resident males of one-male-multi-female primate groups housed at the Hannover Zoo exhibited aggression, when confronted with nonadult individuals, which were fathered by other males: (1) a new adult resident male in a group of blue monkeys killed a 5.8-month-old female infant: (2) a new adult resident male in a group of white collared mangabeys injured a 24.0-month-old female and an 18.9-month-old male severely; they would have died without veterinary care; and (3) the resident male of a group of drills threatened an 1.8-month-old foreign female infant seriously; efforts to introduce the infant were discontinued. Pathological explanations are unlikely because the adult males showed no aggression towards own nonadult offspring under the same captive conditions. By and large, the events support the theory that infanticide is the result of sexual selection among males.     

Reproductive Parameters and Maternal Investment in Mandrills (Mandrillus sphinx)

We report on 14 years of reproductive data for semifree-ranging mandrills (Mandrillus sphinx) in Gabon, and we explore relationships between female rank, age and parity, and reproductive strategies. Most births (61% of 132) occurred during the wet season in Gabon, between January and March. Female rank and parity were unrelated to the timing of parturition. Gestation lengths average 175 days (SE = ±1 day; N = 61) and were similar irrespective of female rank, parity, or sex of offspring. Birth sex ratio did not differ significantly from unity (52% male), and was unrelated to maternal rank or parity. Stillbirths and neonatal mortality tended to be more common among lower-ranking females than among either mid-ranking or dominant females. Median age at first birth is 4.71 years, at a median body mass of 7.6 kg, ca 5 years before females attain their adult body mass (median 12 kg). Age at first reproduction is significantly correlated with dominance rank, with dominant females giving birth on average 1.3 years earlier than lower-ranking females do. Interbirth intervals (IBI) average 405 days (range 184–1159 days, N = 103), and are independent of the sex of the offspring. Infant death within 6 months shortened IBI to 305 days. Increasing age and parity are also associated with short IBI, as is higher rank. Maternal rank and parity appear to influence reproductive success in female mandrills, but there is no apparent differential maternal investment by sex.     

Grooming in mandrills and the time frame of reciprocal partner choice

In this study, we examined the time frame of reciprocal partner choice in the grooming interactions of captive mandrills (Mandrillus sphinx) in order to test the hypothesis that the cognitive limitations of primates constrain the occurrence of reciprocation to short time intervals. In contrast to this hypothesis, mandrills groomed preferentially those individuals that groomed them more even when cases of immediate reciprocation were excluded from the analysis. These results show that mandrills were not limited to reciprocating grooming over short time intervals. It is proposed that a system of emotional bookkeeping may support the ability of primates to reciprocate over long time frames. Am. J. Primatol. 71:884–888, 2009. © 2009 Wiley‐Liss, Inc.     

Serum concentrations of 1,25-dihydroxyvitamin D3 in Platyrrhini and Catarrhini: A phylogenetic appraisal

We measured the serum concentration of 25-hydroxyvitamin D₃ (25-OH-D₃) and 1,25-dihydroxyvitamin D₃ (1,25-[OH]₂-D₃) in 23 different Platyrrhines from four different genera and in 21 Catarrhines from six different genera in residence at the Los Angeles Zoo. The mean (±S.E.) serum concentration of 1,25-(OH)₂-D₃ was significantly greater in Platyrrhines (810 ± 119 pg/ml) than in Catarrhines (61 ± 5 pg/ml), suggesting that high circulating concentrations of the active vitamin D hormone were a characteristic of New World primates in both the Cebidae and Callitrichidae family. This increase in the serum concentration of 1,25-(OH)₂-D₃ is probably an adaptational response on the part of Platyrrhini to offset a relative decrease in the concentration of specific receptor for 1,25-(OH)₂-D₃ in target tissues for the hormone.     

Characterization of microsatellite loci in the brown treecreeper (Climacteris picumnus) and cross‐species amplification in the white‐throated treecreeper (Cormobates leucophaeus)

Eight polymorphic microsatellite markers were developed for the brown treecreeper, Climacteris picumnus. The number of alleles ranged from three to 25 per locus with observed heterozygosities between 0.05 and 0.76. Seven of the eight primer pairs also amplified polymorphic microsatellite loci in the white‐throated treecreeper (Cormobates leucophaeus). These markers are likely to be useful for population genetic and parentage studies in any of the Australasian treecreepers (Climacteridae) and are the first genetic markers developed for any member of this passerine family.     

Social correlates of testosterone and ornamentation in male mandrills

We investigated relationships between fecal androgen concentrations, facial coloration and behaviour in semi-free-ranging male mandrills. We found that fecal androgen levels were significantly positively related to dominance rank, independent of rank stability and the mating period, suggesting that male mandrills live in a permanently aggressive context in which they must actively maintain their dominance status. Facial red coloration was also significantly related to both fecal androgen levels and rank, with high ranking males having both higher androgen levels and redder faces, although dominant males did not always have the highest androgen levels or the reddest faces. Predictive relationships between androgen levels, coloration and rank were short-term. Androgen concentrations and facial redness both increased in the presence of receptive females, as did the former during periods of rank instability. We conclude that male facial redness is likely to represent an honest signal (to other males) of current androgen status, competitive ability and willingness to engage in fights and that females may also use this to assess male condition. Further, our findings provide support for the “challenge hypothesis” as originally proposed for birds by Wingfield.     

Competition for grooming partners and interference in affiliation among female mandrills

Grooming is the most common primate affiliative behaviour, and primates compete for accessing grooming partners. We studied a captive group of mandrills (Mandrillus sphinx) to evaluate the role of different types of competitive interactions in shaping the distribution of grooming among females. Mandrill females preferentially groomed high‐ranking individuals, but low‐ranking females were less able to do so. Interference in others’ grooming and a (consequent) reluctance of low‐ranking females to access dominant group mates occurred frequently and contributed to the observed pattern of grooming distribution, while takeovers of grooming partners was relatively rare. Interference in others’ affiliation was possibly used to prevent the formation of revolutionary alliances. Difficulties in accessing individuals already engaged in grooming exerted a strong but rank‐independent effect on grooming interactions. These results highlight the role of competition in determining access to preferred social partners.     

Life history correlates of inbreeding depression in mandrills (Mandrillus sphinx)

Inbreeding depression reflects the negative consequences of increased homozygosity at genes that affect fitness. We investigate inbreeding depression in a semi-free-ranging colony of mandrills (Mandrillus sphinx), using high-quality pedigree data, comprising five maternal generations and 20 years of morphological and demographic data. We examine the relationship between inbreeding coefficients and four fitness correlates: two growth parameters (mass and height for age) and longevity in both sexes, and age at first conception in females. Inbreeding was correlated with both growth parameters, but only in females, with inbred females being smaller than noninbred females. Inbreeding was also correlated significantly with age at first conception, with inbred females giving birth earlier in life than noninbred females. We suggest that sex-biased maternal investment may explain this sex-differential response to inbreeding, although the lack of a significant association between inbreeding and growth in males may also be due to the provisioned nature of the colony. The surprising relationship between age at first conception and inbreeding may be related to smaller adult size in inbred females, or to their being less able to escape from male sexual coercion.     

圈养山魈繁殖行为的观察

2001 年1～9 月, 在成都动物园用所有事件取样法对人工饲养状态下7 只(5 ♀♀, 2 ♂♂) 山魈的繁殖行为进行了观察。结果表明, 山魈的繁殖没有明显的季节性, 一年四季均发情繁殖, 月经周期为30.55 ±0.77 d (N = 11) , 行经期2.38 ±0.13 d (N = 16) ; 交配行为均发生在白天, 交配持续时间为14.90 ±0.34 s (N = 246) , 具有明显的交配模式, 其中碟牙、爬跨、插入和抽动4 种行为在每次交配中都出现, 交配姿势仅有背腹式一种; 孕期为171.13 ±4.19 d (N = 8) , 产前不废食; 分娩都在夜间进行, 产程2～3 h ; 育幼期哺乳时间随幼仔长大逐渐减少。