| Recent studies of group living in many species of non-human primates indicate that, similar with human society, the coordinated or cooperative action of several individuals can provide multiple benefits to group members, including earlier predator detection, higher foraging efficiency and improved resource defense. Individuals form social relationships by complex behavioral interactions. Some behaviors (e.g., friendly and sexual) improve to maintain social stability, however, some behaviors (e.g., aggressive) destroy social cohesiveness. Thus, social animals have adaptation strategies to balance these two aspects, otherwise the group will be broken.There are abundant of researches about group living and maintaining group cohesiveness. In1970s, some authors hypothesized that exchange among behaviors can buffer competition. In1990s, biological market theory was proposed. Within this framework, grooming can be perceived as a commodity of hygienic value, a commodity of social value, or both, and exchanged for some equivalent commodity in the marketplace that is the social group. To date, there are lots of studies focused on testing the biological market theory, especially in nonhuman primates. Previous studies found some evidence for behavioral exchange/interchange and grooming would be currency for exchange/interchange. However, the type of exchange, partner choice, the relationship between exchange/interchange and group stability are less known. Therefore, the behavioral mechanisam of maintaining group stability can not be demonstrated within the systematic study.The present study, taking Tibetan macaques (Macaca thibetana) as subject, focused on the grooming and other social behaviors (e.g., aggression, copulation), and discussed on the partner choice and its adaptation strategy. The following questions can be answered:(1) what kinds of exchanges in Tibetan macaques?(2) how to select grooming partner for both males and females?(3) what’s the function of male/female for group stability? This study can provide insight into the function of grooming on group stability, promote the study for laws of behavioral economics,.and reveal the -behavioral mechanisim of group stability and cohesiveness.In the present study, using focal sampling methods and continuously recording methods, I obtained behavioral data (311days,1119.33hours) during the study period (May.2009-Aug.2010and Sep.2011). The present study analyzed the dyadic grooming interaction and its adaptation strategy based on analysis of grooming investment among intra-and inter-sexual dyads partner choice, adaptation characteristic and grooming network analysis. The following important results were found as follow:1The present study found the diversity of behavioral exchange/interchange. This study focus on the grooming investment and the relationships between grooming and other social behaviors (i.e., aggression, copulation) among female-female, male-male, and female-male dyads. The results showed that there was variety of behavioral exchange/interchange among Tibetan macaques.(1) Exchange between the same behaviors, such as grooming exchange for itself. Among intra-sexual dyads (female-female and male-male dyads) with the similar dominance hierarchy, grooming investment could exchange for itself with equal values, such as the same frequency or duration. That is to say, grooming reciprocity also occurred principally between individuals of adjacent rank. Correlation tests implied that individuals increased grooming investment with increasing grooming received, and vice versa. Among intra-sexual dyads, when individuals of different rank groomed, individuals tended to groom up the hierarchy, lower-ranking individuals groomed higher-ranking individuals more than vice versa was to increase the tolerance from higher-ranking individuals by aggression reduced.(2) Interchange between different behavior but the same type, such as grooming for tolerance. In intra-sexual dyads with different ranks, tolerance could be as compensation for the disparity of grooming initiated and received.(3) Interchange between different property behaviors, for example, grooming for copulations. In inter-sexual dyads, compared to grooming strategies in intra-sexual dyads, animal individuals pay more attention to the relationship between grooming investment and copulation opportunity. Grooming given was significantly positive correlated with grooming received, however, female individuals groom males at a greater rate and/or for a longer duration during both the mating season and non-mating seasons. High-ranking, middle-ranking, and low-ranking females preferred to groom and/or copulate with high-ranking, middle-ranking, and low-ranking males, respectively. Female-to-male grooming was correlative with copulation indicated that mating opportunity could be as compensation to offset the grooming disparity among female-male dyads.2This study found the partner choice strategy based on grooming interaction in Tibetan macaques. Female philopatry and male dispersal is the important characteristics of Tibetan macaques. Variation of dominance hierarchy, immigrating, emigrating, and fission is the factors of group dynamic. Animals have their own adaptation strategies. The current study analyzed the female-preferred index and partner stability index during the five subperiods with group dynamic. Grooming investment was at a greater and/or longer duration in female-female dyads than male-male and female-male dyads. Partner stability in female-female dyads was higher than both male-male and female-male dyads. These results indicate that Tibetan macaques preferred to groom females and formed stability female partner, which is consistent with group structure of Tibetan macaques.3This study provided the male/female role for group stability. Using social network analysis, the present study analyzed the individual’s role for group stability using strength, eigenvector centrality, clustering coefficient and affinity. Both males and females contributed for the group stability and cohesiveness, however, the eigenvector centrality of females were higher than males’, which represented that female Tibetan macaques contributed more than males. Further, for grooming frequency, hierarchical cluster analysis identified five cliquishnesses clusteed according to matrilineal kin with a cophenetic correlation coefficient of0.816, it suggested matrilineal kinship play an important role in the group of Tibetan macaques. However, for grooming duration, there was no cliquishness, it suggested that in Tibetan macaques, frequently grooming interactions play more important roles for maintaining group cohesiveness than long duration but nonfrequently grooming. On other hand, although females’ clustering coefficient were decreased when male participated, male can be as a adhesive to bridge the behavioral interactions between males and females. Male participation can improve highly the interactions within/among cliquishness, and the cohesiveness among females, males. Therefore, this study give the new evidence of the function for group stability, male participation can promote the group stability and cohesiveness.This study used the combinded idea within the biology, ecology, behavior, economics and sociology. Focal animal sampling and continuous recording (using a digital voice recorder, model News my RV50) were used to score the activity of the focal monkey when following. The aim of the present study was to focus on the relationship between grooming and other social behaviors, to discuss the strategy for group stability based on dyadic grooming interactions. The innovational results were found as followed:(1) This study found the diversity of behavioral exchange/interchange. Behaviors can be exchanged for itself (i.e., grooming for grooming), for other behavior with the same property (i.e., grooming for tolerance), and can also for behavior with different property (i.e., grooming for copulation). This result provides insight into the behavioral mechanism for group stability.(2) Quantitative proved the male’s function for group-living animals. Male participation can improve highly the interactions within/among cliquishness, and the cohesiveness among females, males. Therefore, this study give the new evidence of male’s function for group stability, male participation can promote the group stability and cohesiveness.Maintaining group stability and cohesiveness is the challenge for animals, and it is also a mutual point for zoologists, ecologists, anthropologists and sociologists. Construction of harmonious society need balance the benefit among the whole society. We can get some significant hints from the nature, animals. In view of this point, the present study significantly explained the behavioral mechanism to maintain social bonds and cohesiveness in non-human primates, and also to promote the economic research for evolution of social behaviors. It may open up a new area to concentrate behavior interactions and strategies on both individual and group levels. Meanwhile, this study will help forward conservation and management of Tibetan macaques, and shed light on building harmonious society in human society. |
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