Observed case of maternal infanticide in a wild group of black-fronted titi monkeys (<Emphasis Type="Italic">Callicebus nigrifrons</Emphasis>)

A maternal infanticide was observed in a group of unprovisioned wild black-fronted titi monkeys (Callicebus nigrifrons). An approximately 3-day-old male infant was killed by his mother. A post-mortem revealed the infant to be clinically healthy. We considered various hypotheses to explain why this behavior occurred (e.g., reproductive advantage, stress, nutritional, infant viability and population density). It is noteworthy that the mother and not the father killed the infant, since in this species the father provides considerable infant care from a few hours after birth.     

Adoption in Anthropoid primates

Reports of adoption in nonhuman primates are reviewed, including spontaneous adoptions of orphans or infants whose mothers have been removed from the group, temporary adoptions of offspring of sick mothers, adoptions arising out of kidnapping, and adoptions resulting from manipulations involving presenting infants to adults. Adoptive behavioral patterns resemble nonadoptive alloparental patterns. The literature indicates certain trends: adult females, especially if lactating or in the late stages of pregnancy, are most likely to adopt neonates. Older infants are more likely to be adopted by juveniles or by adult males. Weaned or weanable orphans that get adopted have reasonable chances of survival, while orphans still reliant on milk are unlikely to survive. An infant adopted by an adult female will develop socially as a member of the female’s matriline. Adoptions involving closely related individuals are consistent with kin-selection theory. Others appear to reflect “reproductive error” arising out of an attraction to young infants. Yet other cases might reflect reciprocal altruism. Continued documentation of cases of adoption will yield more data on costs and benefits and on whether rates and forms of adoption, such as alloparental behavior, vary systematically with social systems.     

The variable social organization of hanuman langurs(Presbytis entellus), infanticide,and the monopolization of females

Data from 24 wild populations of hanuman langurs (Presbytis entellus)in south Asia are used to test hypotheses seeking to explain variation in troop structure and the incidence of infanticide. The occurrence of infanticide is associated with a one-male troop structure and not with a high density. The density, predation, and economic-advantage hypotheses, as explanations for the occurrence of one-male and multimale troops, are not supported by the review. However, the monopolization hypothesis is not contradicted; the number of adult males per troop is significantly correlated with troop size and with the number of adult females per troop. Therefore it is suggested that a one-male troop structure will arise if a male is able to monopolize a group of females, a multimale troop if he cannot. One-male troops may predispose to infanticide because of high variance in male mating success and high intermale competition between groups rather than within troops. If female dispersion determines troop structure, it is speculated that females could manipulate males to form a multimale society if the advantages in terms of infant survival and intertroop conflict exceeded the costs in terms of not producing infanticidal “sexy sons.”     

Pollen and resource limitations to lifetime seed production in a wild population of the endangered plant Disanthus cercidifolius var. longipes H. T. Chang (Hamamelidaceae)

Disanthus cercidifolius Maxim. var. longipes H. T. Chang, a plant species that only occurs in a few counties in Hunan, Jiangxi and Zhejiang Provinces and with a relatively small number of individuals, is ranked as a second Class endangered species for conservation in China. We have studied the effect of pollen and resources available to female reproduction, and the reproductive mechanism of “excess flowers with low fruit set” in Disanthus cercidifolius Maxim. var. longipes H. T. Chang was discussed. Results are as follows Pollen from different sources has significant effects on fruit set and seed set of Disanthus cercidifolius Maxim. var. longipes H. T. Chang. The pollen source rather than pollen numbers significantly affected reproduction of this species. In wild populations, producing one fruit needs about 54.8 flowers, and one satiation seed needs about 6.60 flowers or 83.19 ovules. After fertilizing, which was propitious to flower development, the abortion rate of flower buds was decreasing, but the flowering rate was increasing. The fruit set and seed set was also significantly increasing, while abortion rate of fruit was significantly decreasing. With the increasing percentages of cutting leaves, the fruit set decreased, but the abortion rate of fruit shows no significant differentiation among treatments. After cutting branches that were puny, broken and insectin-fested branches, the flower number seemed to be decreasing, but the fruit set and seed set all increased significantly. After removing some flowers, the fruit set was calculated with respect to the number of flowers remaining after the treatment increased with increasing of percentages of flower removal, whereas fruit set calculated with respect to the initial number of flowers remained constant, and the mean weights of per fruit and per seed all decreased significantly. Sufficient spatial or temporal heterogeneities in nutrient levels might allow limitation of seed set by resources and pollen in a natural population, while supplying resources may indirectly affect pollination by increasing attraction of the flowers to pollinators. There were very low fruit and seed sets in natural populations of Disanthus cercidifolius Maxim. var. longipes H. T. Chang. Different factors may have interacted to effect a low fruit set. A joint adoption of the “selection abortion hypothesis”, “ovary reserve hypothesis” and “male function hypothesis” seems to be the most likely explanation for the reproductive strategy of “excess flowers with few fruit sets” in Disanthus cercidifolius Maxim. var. longipes H. T. Chang. __________ Translated from Acta Ecologica Sinica, 2006, 26(2): 496–502 [译自: 生态学报]     

Protein variation,taxonomy and differentiation in five species of marmosets (genusCallithrix Erxleben, 1777)

The electrophoretic patterns of 15 protein systems codified for 20 genetic loci were investigated using horizontal electrophoresis. A total of 150 blood samples, from five species of the genusCallithrix were analyzed. Polymorphic variation was observed in 10 out 20 loci analyzed. The genotypic distributions are in Hardy-Weinberg equilibrium. The average heterozygosity (H) varied from 1% to 5%, similar to those observed for other Neotropical primates. The genetic distance coefficients revealed a phylogenetic separation of these species into two groups: (1) “argentata” (C. humeralifer andC. emiliae); (2) “jacchus” (C. jacchus, C. penicillata, andC. geoffroyi). This arrangement is according to the taxonomic arrangement proposed byHershkovitz (1977),de Vivo (1988), andMittermeier et al. (1988). The results in each group are compatible with the subspecies values recorded for the Platyrrhini. These values showed that:C. humeralifer andC. emiliae are subspecies ofC. argentata;C. jacchus, C. penicillata, andC. geoffroyi are subspecies ofC. jacchus. These results also suggest thatC. j. geoffroyi is the “jacchus” group taxon, most similar genetically to the “argentata” group.     

Adoption in free-ranging red howler monkeys,Alouatta seniculus of Venezuela

This report describes three cases of infant adoption in red howler monkeys (Alouatta seniculus) of Venezuela. In one case, a lactating female adopted her infant granddaughter after the infant's mother disappeared and the infant survived for the next 25 months. In the second case, an adult female adopted her infant granddaughter for nine days while the infant's mother was still a group member. In the third case, a nulliparous female temporarily adopted an infant from a neighboring group. The details and the possible reasons for these adoption are described.     

Nest-site habitat selection by Lesser Rheas ( Rhea pennata pennata ) in northwestern Patagonia, Argentina

Selection of nest-site habitat by a population of wild Lesser Rheas (Rhea pennata pennata) was studied in the northwestern Patagonia steppe, Argentina, during two reproductive seasons (2004/2005 and 2005/2006). Nest spatial distribution was compared with randomly selected points in the study area. Contrary to observations in other ratite species, nest distribution showed an aggregate pattern associated with “mallín” (meadow) areas, which are habitats of higher productivity in the Patagonia steppe. Moreover, similar to observations made on the Greater Rhea (Rhea americana), vegetation cover was higher in nest sites than in randomly selected sites, probably because higher vegetation provides concealment from predators and protection from the strong westerly winds that frequent in this region. Our results reinforce the importance of “mallín” areas for the reproduction and conservation of this threatened ratite species.     

Peering in mature, captive bonobos (Pan paniscus)

“Peering”—close-proximity staring at the mouth of another—was observed in ten (three males and seven females) mature (at least 7 years old) bonobos (Pan paniscus) living in three social groups at the San Diego Zoo and Wild Animal Park. Instantaneous scan samples, taken at 2-min intervals, over a three-and-a-half year period, yielded 617 observations of peering (1.4 per observation hour). Food was exchanged in only 15 of these scans. Peering was most often performed by younger animals and was primarily directed toward older females (“matrons”). In a given dyad, the animal more likely to peer at the other was also more like to both peer and be peered at if they frequently groomed and infrequently displayed aggression at a given female. An adolescent male showed the highest frequency of peering when living with two older females, but dropped to adult male levels when later housed with two younger (albeit mature) females. A reversal in which animal was more likely to peer, follow, and groom occurred in one female dyad, after the birth of the younger animal's first infant. After a similar birth in the other group, no such changes were observed. We discuss how these and related findings, in conjunction with what is known of the social structure of this species, suggest that one possible function of peering in bonobos may be as a signal acknowledging female status.     

Social integration of a bonobo mother and her dependent daughter into an unfamiliar group

In the present study, we obtained quantitative behavioral data on the integration process of an adult female with her dependent daughter into a resident zoo population of six bonobos (Pan paniscus). During the whole observation time of almost two months, the integration happened very peacefully without significant increases of aggressive or agonistic tendencies. The integration was mediated and actively supported mainly by two processes: contacts of resident infants and juveniles towards the immigrating animals and contacts of the immigrating adult female to a “specific senior female” of the resident group. Adult males and adolescent females seemed not to play a role in the social integration of new group members. The new adult female soon became a preferred partner for sexual interactions such as genito-genital rubbing. The social integration of the 18-month-old young was controlled by her mother and finished only after the adult female had reached a stable and safe position in the new group. According to our observations, the exchange of an adult female bonobo including her young between zoos has no negative effects on the animals involved.     

Characterization of some fish and shrimp spoiling bacteria

The classification of some important groups of bacteria involved in fish and shrimp spoilage was studied. Trimethylamine is produced byPseudomonas putrefaciens, a “non-defined” group resemblingPs. putrefaciens, Photobacterium spp. and someMoraxella-like bacteria. Hypoxanthine is produced by the same groups of bacteria except the last named and also by the “typical shrimp spoilers” (presumptiveAlteromonas). Strong off-odours are produced on fresh fish byPs. putrefaciens, dextroseoxidativePseudomonas spp. (Groups I and 11 according to Shewan, Hobbs and Hodgkiss, 1960), the above mentioned “non-defined” group and by only some of the “typical shrimp spoilers”, whereasMoraxella-like bacteria andPhotobacterium spp. failed to produce strong odours. Strong off-odours are produced on boiled shrimp by the “typical shrimp spoilers” (presumptiveAltermonas),Ps. putrefaciens, the dextrose-oxidativePseudomonas spp. and the “non-defined” group;Moraxella-like bacteria produced less offensive odours or none, nor didPhotobacterium.     

Observations on the meat-eating behavior of wild bonobos (Pan paniscus) at Wamba,Republic of Zaire

Meat-eating behavior of wild bonobos (Pan paniscus) was witnessed on two occasions at Wamba, Republic of Zaire. Only flying squirrels were observed to be eaten by the bonobos. Several bonobos gathered around the possessor of the meat and showed interest in the meat on all occasions. Begging behavior was noted on one of the two occasions, but the possessor of the meat ignored it. No sharing of meat was seen on either occasion. The exclusive targets of hunting by bonobos are apparently small mammals, such as flying squirrels and infant duikers, since evidence of meat eating by wild bonobos, which have been studied for more than fifteen years, has been restricted to these mammals. The bonobos at Wamba may have a specialized “prey image”, as in the case of the chimpanzees (Pan troglodytes) of the Tai forest, and certain medium-sized or small mammals may not conform to this image.     

Integration of a hand-reared chimpanzee (Pan troglodytes) infant into a social group of conspecifics

Rejections of infants among non-human primates occasionally occur in the wild as well as in captive settings. Controlled adoptions of orphans and introductions of individuals into new groups are therefore sometimes necessary in captivity. Consequently, behavioral research on integration procedures and on the acceptance of infants by adoptive mothers is much needed. In this study, the introduction and subsequent adoption were examined in an 18-month-old hand-reared chimpanzee (Pan troglodytes). The infant was introduced into an age/sex-diversified social group of conspecifics at Furuvik Zoo, Gävle, Sweden, and continuous focal data was collected during the final stage of integration, including infant care exhibited by the group members and the infant’s secure base behavior. The infant was successfully integrated into the group and engaged in positive social interactions with all group members. An adult primiparous female chimpanzee formed a bond resembling a mother–infant relationship with the infant, which continues to be maintained at publication. However, the female initially showed very limited interest in the infant. It was, in fact, two other younger female group members that exhibited most infant care. The infant’s secure base behavior patterns indicate that she adapted well to the new circumstances in the chimpanzee group as the integration progressed. This provides evidence that a final adopter does not necessarily initially show maternal interest and that there can be flexibility in maternal behavior in adult chimpanzee females. Moreover, the methods applied employing gradual familiarization with all the group members and the use of an integration enclosure, may have contributed to a successful result. These findings extend our knowledge of introduction procedures in captivity as well as provide information on foster mother–infant attachment in chimpanzees.     

Fitness consequences of anthropogenic hybridization in wild red-legged partridge (Alectoris rufa, Phasianidae) populations

Hybridization is a widespread phenomenon, which plays crucial roles in the speciation of living beings. However, unnatural mixing of historically isolated taxa due to human-related activities has increased in recent decades, favouring levels of hybridization and introgression that can have important implications for conservation. The wild red-legged partridge (Alectoris rufa, Phasianidae) populations have recently declined and the releases of farm-reared partridges have become a widespread management strategy. The native range of the red-legged is limited to the south-west of Europe (from Italy to Portugal). This species does not breed in sympatry with the chukar partridge (A. chukar), whose range is Eurasian (from Turkey to China). However, red-legged partridges have often been hybridized with chukar partridges to increase the productivity of farmed birds, and game releases may have spread hybrid birds into the wild. In this study, we investigated the fitness (survival and breeding) differences between hybrid and “pure” red-legged partridges in a wild population located in central Spain. Incubation probability was similar in hybrids and “pure” partridges. Hybrid females laid larger clutches than “pure” ones, but hatching success did not differ between hybrid and “pure” partridges. Hybrid birds had lower survival rate than “pure” ones, mainly because of higher predation rates. Our results show that, despite lower survival, hybrid partridges breed in natural populations, so this could increase extinction risk of wild pure partridge populations, through releases of farmed hybrid birds. The consequences of continued releases could be of vital importance for the long term conservation of wild red-legged partridges.     

Pollination biology of <Emphasis Type="Italic">Disanthus cercidifolius</Emphasis> var. <Emphasis Type="Italic">longipes</Emphasis>, an endemic and endangered plant in China

Disanthus cercidifolius Maxim. var. longipes H.T. Chang usually has two inflorescences growing in opposite directions in the axillae, but occasionally three inflorescences grow paratactically. The typical flowering process could be divided into 4 periods: “Pre-dehiscence”, “Initial dehiscence”, “Full dehiscence” and “Withering”. Both the natural population and the planted population had a flowering peak of 15–35 days after the first flower bloomed. There were significant differences between the time courses of flowering of the two populations. Out-crossing is the main breeding system in this species. And autogamy decreases the risk of reproductive failure of this species. The main insect pollinators of D. cercidifolius var. longipes are Episyrphus balteatus de Geer, Scaptodrosophila coracina Kikkawa and Peng, Polistes olivaceus de Geer, Apis cerana Fabricius, Nezara viridula L. and Coccinella septempunctata L., and so on. Among the insects, S. coracina and E. balteatus are the most important and efficient pollinators, but others are inefficient pollinators. Though wind pollination is not efficient, it guarantees reproduction when insect pollinators are not available. “Mass flowering” is an adaptive behavior and reproductive strategy of this species, and “few fruiting” could be caused by the lack of pollinators.     

First occurrence of twins in provisioned free-ranging Tibetan macaques (Macaca thibetana) at Huangshan, China

A first case of newborn Tibetan macaque (Macaca thibetana) twins was observed in a free-ranging group at Huangshan, China. The female that gave birth to the twins was studied during their first 5 months post-partum, and her activity budget was compared to those of adult females with single or no offspring in order to assess her behavioral changes. Our report shows that female Tibetan macaques can produce twins, and that twins can successfully survive. The adult female with twins spent more time foraging and resting, but less time moving and engaged in other social behaviors than adult females with a single infant or no infant. Our report provides a case of successfully surviving twins in a wild environment and suggests that the mother modified her behavior patterns to adapt to the heavy burden. We conclude that both food provisioning and the mother’s behavioral strategies facilitated the survivorship of twins. This expands our understanding of the reproductive biology of Tibetan macaques.     

Long-term Study of Group Dynamics and Female Reproduction in Venezuelan Pithecia pithecia

White-faced sakis (Pithecia pithecia) are well known for their specialized feeding strategy and dependence on seed-eating, but we know less about social dynamics and reproduction. I summarize data from 1990 to 2001 on sakis inhabiting a small island in Lago Guri, Venezuela that includes changes in group composition, aggressive behavior, and female reproductive histories. Though the characteristic group size and typical mating system are still uncertain for wild, free-ranging Pithecia spp., size of the study group ranged from 2–3 adult females and 1–4 adult males. My group and I collected fecal samples from adult females, which we dried and assayed for estrogen (E₁C) and progesterone (PdG) conjugates to document reproductive cycles and female development. During the study, as many as 3 females were either cycling or pregnant at the same time. Ten infants were born during the study, 4 of which survived to adulthood. Five interbirth intervals after weaning an infant ranged from 12 to 36 mo. Though researchers often assume Pithecia spp. are monogamous, multiple breeding females can coexist in groups without evidence of reproductive suppression. Within the pitheciine clade, Pithecia spp. exhibit a mosaic of behavioral and morphological traits intermediate between bearded sakis and uakaris on the one hand and their sister-group, the pair-bonded titis, on the other.     

Systematics and genetic variation in commercial shape Kappaphycus and shape Eucheuma (Solieriaceae, Rhodophyta)

The systematics and taxonomy of Kappaphycus and Eucheuma (Solieriaceae) is confused and difficult due to morphological plasticity, lack of adequate characters to identify species and commercial names of convenience. These taxa are geographically widely dispersed through cultivation. Commercial, wild and herbarium sources were analysed; molecular markers provided insights into taxonomy and genetic variation, and where sources of genetic variation may be located. The mitochondrial cox2-3 and plastidal RuBisCo spacers were sequenced. There is a clear genetic distinction between K. alvarezii (“cottonii”) and K. striatum (“sacol”) samples. Kappaphycus alvarezii from Hawaii and some samples from Africa are also genetically distinct. Our data also show that all currently cultivated K. alvarezii from all over the world have a similar mitochondrial haplotype. Within Eucheuma denticulatum (“spinosum”) most African samples are again genetically distinct. Our data also suggest that currently cultivated E. denticulatum may have been “domesticated” several times, whereas this is not evident for the cultivated K. alvarezii. The present markers used do not distinguish all the morpho-types known in cultivation (e.g. var. tambalang, “giant” type) but do suggest that these markers may be useful to assess introductions and species identification in samples.     

Comparing infant and juvenile behavior in bonobos (Pan paniscus) and chimpanzees (Pan troglodytes): a preliminary study

The dichotomy between the two Pan species, the bonobo (Pan paniscus) and chimpanzee (Pan troglodytes) has been strongly emphasized until very recently. Given that most studies were primarily based on adult individuals, we shifted the “continuity versus discontinuity” discussion to the infant and juvenile stage. Our aim was to test quantitatively, some conflicting statements made in literature considering species differences between immature bonobos and chimpanzees. On one hand it is suggested that infant bonobos show retardation in motor and social development when compared with chimpanzees. Additionally it is expected that the weaning process is more traumatic to chimpanzee than bonobo infants. But on the other hand the development of behaviors is expected to be very similar in both species. We observed eight mother–infant pairs of each species in several European zoos. Our preliminary research partially confirms that immature chimpanzees seem spatially more independent, spending more time at a larger distance from their mother than immature bonobos. However, the other data do not seem to support the hypothesis that bonobo infants show retardation of motor or social development. The development of solitary play, environmental exploration, social play, non-copulatory mounts and aggressive interactions do not differ between the species. Bonobo infants in general even groom other group members more than chimpanzee infants. We also found that older bonobo infants have more nipple contact than same aged chimpanzees and that the weaning process seems to end later for bonobos than for immature chimpanzee. Additionally, although immature bonobos show in general more signs of distress, our data suggest that the weaning period itself is more traumatic for chimpanzees.     

Unadapted behaviour of native,dominant ant species during the colonization of an aggressive,invasive ant

Among the factors driving the invasive success of non-indigenous species, the “escape opportunity” or “enemy release” hypothesis argues that an invader’s success may result partly from less resistance from the new competitors found in its introduced range. In this study, we examined competitive interactions between the little fire ant Wasmannia auropunctata (Roger) and ant species of the genus Pheidole in places where both are native (French Guiana) and in places where only species of Pheidole are native (New Caledonia). The experimental introduction of W. auropunctata at food resources monopolized by the Pheidole species induced the recruitment of major workers only for the Guianian Pheidole species, which were very effective at killing Wasmannia competitors. In contrast, an overall decrease in the number of Pheidole workers and no recruitment of major workers were observed for the New Caledonian species, although the latter were the only ones able to kill the Wasmannia workers. These results emphasize the inappropriate response of native dominant New Caledonian species to W. auropunctata and, thus, the importance of enemy recognition and specification in the organization of ant communities. This factor could explain how invasive animal species, particularly ants, may be able to successfully invade species-rich communities.