Sexual dimorphism in responses to unfamiliar intruders in the tamarin, Saguinus oedipus

Aspects of social structure in group-living species can be inferred by observing the responses of individuals to unfamiliar animals. This study examined the responses of mated pairs of cotton-top tamarins (Saguinus oedipus oedipus) to presentation of either unfamiliar conspecifics or members of a related tamarin species, the saddle-back tamarin (Saguinus fuscicollis fuscicollis). Male and female responses to intruders differed: resident males threatened, displayed piloerection, approached, and attacked intruders, especially males, while resident females showed increases in suprapubic scentmarking in the presence of intruders. Both males and females discriminated between the species of intruders, exhibiting more threats, scent-marking, piloerection, and approaches in the presence of conspecific intruders. There are pronounced sex differences in the signals and behaviour patterns that are elicited in an aggressive or territorial encounter with unfamiliar conspecifics in this monogamous primate.     

Mating behavior of Aegla platensis (Crustacea, Anomura, Aeglidae) under laboratory conditions

The mating behavior of several decapod crustaceans has been extensively studied; however, this aspect of anomuran biology is still poorly known in some groups. Aeglids are the only anomurans inhabiting freshwaters, and the mating behavior of the species in this family is unknown. We provide the first account of the mating behavior of an aeglid, Aegla platensis, under laboratory conditions. The precopulatory phase was characterized by male agonistic display, male approach, and courtship. Males exhibited the agonistic display toward immature and mature females, but only physiologically mature females allowed males to approach. Male approach led to display of courtship behaviors (body vibration, thrust, body lifting, and abdomen flapping). During the copulatory phase, males and females touched each other with the antennae (antennae touch), and males positioned themselves beneath the females (supine position). Although sperm transfer was not directly observed, a “white mass” was detected among oocytes in the female abdominal chamber shortly after some copulations. Finally, in the postcopulatory phase, males guard females during the process of egg attachment. Despite their morphological similarities with other anomurans, the mating behavior of aeglids seems to be unique, and the freshwater environment appears to have an important role in driving these differences.     

The Pair-Bond Formation and Its Role in the Stimulation of Reproductive Function in Female Common Marmosets (Callithrix jacchus)

The sociosexual relationship between male and female common marmosets (Callithrix jacchus) is characterized by pair-bond formation, which includes sexual and social interactions such as contact, huddling and allogrooming. The formation of heterosexual pairs in captivity sometimes is unsuccessful in terms of reproduction. We investigated the existence of a correlation between characteristics of sociosexual interaction of marmoset pairs and its role in stimulating reproductive function in females. We studied pair-bond formation during the first 10 weeks of pairing in eight unrelated heterosexual pairs of common marmosets (Callithrix jacchus) without prior sexual experience. In three of them, pregnancy occurred during the study period (group SR), and we compared the profile of their sociosexual interactions with that of the five other couples in which pregnancy was not registered (group NS) during that period. The results show differences between the two groups, related mainly to affiliative responses between male and female, with significantly higher levels of allogrooming and simultaneous piloerection in the SR group. Although we did not find significant differences in the frequency of mounting behavior between groups, their reproductive success was different, suggesting that some behavioral patterns related to cooperative interactions between the male and female could be expressing the pair-bond. These behaviors may be influencing the females' physiology and consequently successful reproduction in the species.     

Effects of sibling-rearing experience on future reproductive success in two species of callitrichidae

The survival rate for offspring of mothers who either had or did not have previous experience rearing younger siblings was compared in two callitrichid species, Callithrix jacchus and Saguinus oedipus. Offspring of mothers with sibling-rearing experience had a higher survival percentage than offspring of inexperienced mothers in both species. While 50–60% of offspring of inexperienced C. jacchus mothers survived, no offspring of inexperienced S. oedipus mothers survived. The results suggest that sibling-rearing experience is necessary for adequate maternal behavior in S. oedipus, but not necessary to the development of maternal behavior in C. jacchus. Effects of previous sibling-rearing experience of S. oedipus fathers on offspring survival were also examined. Whether the father had rearing experience was not related to the survival of their offspring.     

Chromosome studies of Saguinus midas niger (Callithricidae,Primates) from Tucurui,Para, Brazil: Comparison with the karyotype of Callithrix jacchus

The karotype of Saguinus midas niger was studied by G-, C-, and nuclear organizer region (NOR)-banding techniques. Variations in C-banding patterns were observed in some chromosomes. The banding patterns obtained were compared with those previously described for Callithrix jacchus. The two species differ by a reciprocal translocation involving pairs 9 and 16; by a paracentric inversion in chromosomes 1, 13, 14, 18, and 22; and by a pericentric inversion in at least four subtelocentric pairs (chromosomes 19, 20, 21, and 22), dislocating the nucleolar organizer region from the small short arm in C. jacchus to the proximal segment of the long arm in S. m. niger (or vice versa). The amount of constitutive heterochromatin is greater in S. m. niger than in C. jacchus, especially in chromosomes 4, 7, and 14. The Y chromosome is smaller in C. jacchus than in S. m. niger.     

Agonistic Displays and the Benefits of Fighting in the Field Cricket, Gryllus bimaculatus

Fighting is often composed of discrete agonistic displays. Few studies have partitioned fighting behavior into its component agonistic displays and evaluated the relationships between the frequency of the displays and the potential benefits of fighting, particularly mating success. In this study, we quantified the frequency of male field cricket, Gryllus bimaculatus, agonistic displays. The displays were quantified under three social environments which varied in the potential benefits of fighting: males with other males only, males with other males and female scents, and males with other males and females. We found that (1) the presence of females elicited an increase in agonistic displays characteristic of intermediate levels of escalation, (2) female scents did not produce a similar increase in the frequency of agonistic displays, and (3) in the presence of females, the frequency of agonistic displays was positively correlated with mating success. Aggressive stridulation, an energetically low-cost display, was more strongly associated with mating success than were more costly displays. The results are discussed in the context of the evolutionary theory of aggression and in the context of cricket mating systems.     

Reproductive performance of three species of Callitrichidae

The reproductive performance of three species of Callitrichidae housed under identical conditions, including relatively spacious caging and visual screening, was compared. The three species were Callithrix jacchus, Saguinus fuscicollis, and Saguinus oedipus. Callithrix jacchus was the most reliable breeder, with the lowest percentage of stillborn and the highest post-weaning survival. While the reproductive performance of S oedipus was better than that generally reported for other colonies, the reproductive performance of the Saguinus species was still poorer than that of C jacchus. The two Saguinus species did not differ significantly in either percentage of stillborn or post-weaning survival. None of the species showed infertility due to lactation, but the mean inter-birth interval was significantly longer for S oedipus than for either C jacchus or S fuscicollis.     

Comparison of infant care in family groups of the common marmoset (Callithrix jacchus) and the cotton-top tamarin (Saguinus oedipus)

The involvement of parents and siblings in infant care in similarly composed groups of common marmosets (Callithrix jacchus) and cotton-top tamarins (Saguinus oedipus) was compared during the infants' first 8 weeks of life. The results indicate an earlier infant independence in C. jacchus than in S. oedipus due primarily to a more frequent rejection of carried infants in C. jacchus. There was no species difference in extent of maternal involvment in carrying infants. However, S. oedipus fathers carried infants significantly more often during weeks 5–8 than did C. jacchus fathers. Siblings were generally more involved in infant care at an earlier infant age in C. jacchus than in S. oedipus.     

Social organization in a wild population ofCallithrix jacchus: II. Intragroup social behavior

The social behavior of the common marmoset has been well studied in captivity, but little is known about the social dynamics of this species in its natural habitat. Social relationships were studied in three polygynous groups of common marmosets,Callithrix jacchus, in northeastern Brazil. Breeding adults appeared to be the center of social life and were the most frequent grooming partners or nearest neighbors for most adult group members. The observations of unidirectional agonistic interactions suggest that breeding adults were also dominant over all other group members, but that neither sex was dominant over the other. The dynamics of within-group social relationships are likely to be important determinants in the reproductive strategies employed by marmoset females.     

Social implications of gummivory in marmosets

Gummivory or exudate feeding is a major dietary specialization which has received relatively little attention in the literature. While plant exudates contribute to the diet of many primate species, we suggest that the callitrichid species Cebuella pygmaea and Callithrix jacchus are obligate exudate feeders under free-ranging conditions. Callithrix jacchus provides an excellent model for examining the effects of exudate feeding and foraging upon social behavior, since other callitrichid species of similar body size do not share this dietary specialization. We review the effects of exudate foraging on specific social behaviors observed both in field and laboratory populations of C. jacchus. By comparing this species to closely related species, exudate foraging is seen to (1) be retained under laboratory conditions, (2) increase the frequency of territorial marking behavior while decreasing the frequency of overt aggression in males, (3) decrease the duration of infant care, and (4) increase the number of nonadults in social groups but not affect group size. The evidence presented supports the hypothesis that the consequences of exudate foraging in C. jacchus are fundamental and socially complex. © 1994 Wiley-Liss, Inc.     

The Influence of Male Body Size and Social Environment on the Mating Behavior of Phallichthys quadripunctatus (Pisces: Poeciliidae)

In some poeciliid fishes, variation in male size is accompanied by differences in mating behavior. Large males are preferred by females and perform courtship displays followed by copulatory thrusts, whereas small males perform copulatory thrusts with few or no displays. This phenomenon has been described in only a few genera and little is known about mating behavior in other poeciliids. Although Phallichthys quadripunctatus males display size dimorphism that has a genetic component, mating behavior of this species has not been documented. We conducted experiments using socially experienced and socially naive males to characterize the mating behavior of this species and to evaluate potential size-dependent differences in behavior. Males were tested with postpartum (presumably receptive) and midcycle (presumably unreceptive) females in different social environments. Whereas neither size class of P. quadripunctatus males performed courtship displays or altered behavior based on female receptivity, large males performed several reproductive behaviors more frequently than small males. This trend was repeatable and occurred in all social environments examined. Some males also attempted to mate with other males, with small males showing a greater tendency to perform this behavior than large males. The manner in which differences in reproductive activity translate into differences in reproductive success must be examined before inferring sexual selection favoring large males in P. quadripunctatus.     

Floor-coverings and hanging screens alter arboreal monkey behavior

The use of floor-covering has been shown to substantially alter the behavior of captive terrestrial primates. Experiments with two large family groups of common marmosets (Callithrix jacchus) and two of cotton-top tamarins (Saguinus oedipus) have shown that the type of floor-covering also beneficially alters the behavior of arboreal monkeys, increasing use of the floor and decreasing inactivity. These effects increased over 2.5 mo, and appeared to be due to the reduced aversiveness of the floor. Hanging screens also produced beneficial effects.     

Relationship between social interactions and sexual maturation in female Saguinus oedipus oedipus

4 female Saguinus oedipus oedipus were paired with strange, unrelated males while 5 remained in their natal family groups. A comparison of the frequency of selected social interactions involving these females when sexually immature versus mature was made. The frequency of sexual and affiliative interactions in male-female pairs was basically unchanged by the female's maturation. Mother-daughter interactions were also not changed in a consistent fashion by the daughters' maturation. Females with strange, unrelated males, either alone or as part of their natal group, displayed increases in marking behavior in association with sexual maturation.     

Temporal Pattern of Agonistic Interaction in Two Gerbil Species (Rhombomys opimus and Gerbillus perpallidus) Differing in Resistance to Social Pressure

This study compares temporal patterns of intraspecific agonistic interactions in two gerbil species in order to indicate interspecific differences in levels of social resistance. Both cross-sex and same-sex pairs of great gerbils (Rhombomys opimus Licht., 1823), and only same-sex male pairs of pallid gerbils (Gerbillus perpallidus Setzer 1958) were observed during staged encounters on a neutral arena. Analysis of three latency measures—latency to first agonistic interaction; latency to overt aggression (attack and/or ‘arrested’ fight); and latency to establishment of a stable winner-loser asymmetry among opponents—revealed both similarities and differences among the species. Latencies to first agonistic interaction were similar (did not differ significantly) among species and sexes. However, great gerbil males showed significantly more long latencies to establishment of a stable asymmetry among opponents, than great gerbil females or pallid gerbil males. So, the periods of symmetrical struggle in agonistic conflict last longer in great gerbil males, than in great gerbil females or pallid gerbil males. These differences in temporal pattern of agonistic interaction may reflect sex and species differences in resistance to social stress.     

Pregnancy weight gain: marmoset and tamarin dads show it too

Paternal behaviour is critical for the survival of offspring in many monogamous species. Common marmoset (Callithrix jacchus) and cotton-top tamarin (Saguinus oedipus) fathers spend as much or more time caring for infants than mothers. Expectant males of both species showed significant increases in weight across the pregnancy whereas control males did not (five consecutive months for marmoset males and six months for cotton-top tamarin males). Expectant fathers might be preparing for the energetic cost of fatherhood by gaining weight during their mate's pregnancy.     

Virgin females compete for mates in the male lekking species Ceratitis capitata

Abstract. Aggressive behaviour occurring in intrasexual competition is an important trait for animal fitness. Although female intrasexual aggression is reported in several insect species, little is known about female competition and aggressive interactions in polygynous male lekking species. The interactions of female Mediterranean fruit flies, Ceratitis capitata (a male lekking species), with other females and mating pairs under laboratory conditions are investigated. Mature, unmated (virgin) females are aggressive against each other and against mating pairs, whereas immature females are not. Female aggression against other females decreases dramatically after mating; however, mated females maintain aggression against mating pairs. In addition, higher intrasexual aggression rates are observed for mature, virgin females than for virgin males of the same age. The results show that female aggressiveness is virginity related, suggesting female competition for mates. These findings have important implications for understanding the physiological aspects of a complex social behaviour such as aggression and should stimulate further research on female agonistic behaviour in male lekking mating systems.     

Chemical communication of reproductive status in female cotton-top tamarins (Saguinus oedipusoedipus)

Among Callitrichids, scent secretions have been identified as carrying information regarding species, subspecies, gender, social status, individuality, hormonal status, and timing of ovulation. We propose that information regarding familiarity and reproductive status is also communicated. Seven male–female pairs of cotton-top tamarins (Saguinus oedipus oedipus) were presented with several drops of distilled water, a scent secretion from the female of that pair, scent secretions from unfamiliar, reproductively mature but noncycling females, and scent secretions from unfamiliar, reproductively cycling females. Behavioral responses from both males and females were recorded over a 10 min period. Differences in behavioral response for both males and females were significant across all four conditions. This indicates that cotton-top tamarins are capable of discriminating a familiar scent from an unfamiliar scent as well as the reproductive status of an unfamiliar female. The communication of this information may play an important role in regulating mate selection, reducing reproductive competition, and stabilizing transfers in and out of groups in the wild. Am. J. Primatol. 45:337–349, 1998. © 1998 Wiley-Liss, Inc.     

Some Evolutionary Aspects of the Food-Procuring Group Behavior in Phylogenesis of Primates

The peculiarities were studied of the intragroup competitive and cooperative behavior of primates differing by the level of phylogenetic development, beginning from low-organized species of the higher primates to high-organized anthropoid monkeys (Callithrix jacchus, Cebus apella, Macaca mulatta, Papio hamaofrijas, Pan troglodytes). It has been shown that in all monkeys, under conditions of competitive feeding situation, there were changes of the complex behavioral forms observed at individual learning. Under conditions of the activity in pairs, the females of platyrrhine (New World) and lower narrow-nose (Old World) monkeys lost the possibility to realize the skill and food needs, so the programmed tasks were solved predominantly by the males. In chimpanzees, the change of indices of instrumental activity involved to the equal degree the male and female, and solution of the alternation task was higher in individual experiments. The age differences were revealed in the competitive behavior of chimpanzees in group. The realization of formed skills depended on the complex of factors including the requirements dominating in the given situation and the age and typological peculiarities, as well as the social rank of each monkey in the community. In rhesus macaques the capability for cooperative interaction was revealed under conditions of complex operant activity.     

Chromosomal evolution inCallithrix emiliae

We studied the karyotype of specimens ofCallithrix emiliae (Callithricidae, Primates) from Rondonia, Brazil. Comparison with the karyotype ofCallithrix jacchus showed that, even though these two species show many karyotypic similarities, they differ by a Robertsonian translocation, a paracentric inversion and large-scale addition of heterochromatin. TheC. emiliae species appears to be in an active phase of chromosome evolution by the addition of constitutive heterochromatin.     

Red-bellied tamarins (Saguinus labiatus): Hematologic reference values and hemopathologic responses

Hematologic reference values have been established for captive adult red-bellied tamarins (Saguinus labiatus) by carrying out full blood counts and fibrinogen estimations on 25 clinically normal animals. The only significant sex difference detected was in the reticulocyte count which was higher in females than in males. The reference values were used to identify abnormal changes in the blood of nine clinical cases. Hypochromic anemia, neutrophilia, and raised fibrinogen levels were found in animals with self-inflicted injuries, dermatitis, and ileocecal intussusception. Target cells and jaundiced plasma were noted in a case of yersiniosis. Two animals in which generalized muscle wasting was the main abnormal clinical sign were severely anemic, and in one of these cases a significant number of Heinz bodies was present. The findings in these two animals were compared with those in common marmosets (Callithrix jacchus) with possible wasting marmoset syndrome.