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Rebecca J Lewis

Publications and source records attributed to Rebecca J Lewis.

4 recordsLinked to original sources
PubMed2006

Scent marking in sifaka: no one function explains it all.

Various hypotheses to explain possible functions of scent-marking have been put forth and basically fall into five categories: territorial demarcation, ownership of resources, mate attraction, noncombative fighting, and self-advertisement. Verreaux's sifaka (Propithecus verreauxi verreauxi), like many prosimians, use scent-marking as one form of communication. The goal of this study was to determine the function of scent-marking in sifaka. All-occurrence of scent-marks, scent-mark context, and scent-mark style were collected on 23 sifaka in the Kirindy Forest of western Madagascar for 7 months (September 2001-March 2002). Scent-mark rates were collected using continuous focal animal sampling from November 2000-March 2002. Home range data were collected using monthly censuses and instantaneous focal sampling throughout the 17 months. Scent-marking behavior was exhibited almost exclusively by adults. Scent-mark rates were not related to the number of resident adult males, number of resident adult females, rank, or group size. The majority of scent-marks occurred in the perimeter of the home range; however, less than a quarter of the home range was used by only a single group. Sifaka did not preferentially mark food trees, mark during the mating season, or mark during intergroup encounters. The results from this study indicate that none of the five hypothesized functions best explains all scent-marking in Verreaux's sifaka. Rather, scent-marking may serve different functions for different individuals.

Animal Communication↗
PubMed2005

Sex differences in scent-marking in sifaka: Mating conflict or male services?

Male and female interests can either be in conflict or serve as a basis for exchange. Communication is thus an important aspect of intersexual relationships. Verreaux's sifaka (Propithecus verreauxi verreauxi), like many prosimians, uses chemical signals as one form of communication. The goals of this study were to determine 1) if males and females exhibit sex differences in their scent-marking behavior, and 2) if scent-marking is an example of mating conflict or cooperation. All occurrences of scent-marks, scent-mark context, and scent-mark style were collected on 23 sifaka in the Kirindy Forest of western Madagascar for 7 months (September 2001-March 2002). Scent-mark rates were collected using continuous focal animal sampling from November 2000-March 2002. Home-range data were collected using monthly censuses and instantaneous focal sampling throughout those 17 months. The pressures of behavioral ecology seem to have shaped scent-marking in sifaka: the sexes exhibited significantly different scent-marking behavior. Results from this study are consistent with the hypotheses that 1) females scent-mark to advertise their presence and mark their resources, 2) clean-chested males use scent-marks as between-group communication to advertise their presence, and 3) stained-chested males use scent-marks as a form of olfactory mate-guarding. Scent-marking does not appear to be a "service" that males provide to females, because overmarking limits female communication rather than adding to the overall number of scent-marks. Scent-marking behavior is a crucial aspect of the mating conflict and for understanding intersexual relationships in sifaka.

Animal Communication↗
PubMed2002

Beyond dominance: the importance of leverage.

The dominance concept as it is currently defined and applied in animal behavior is problematic. What has been traditionally considered dominance is actually a combination of dominance in the strict sense and power based upon other sources. Rather than working within the current paradigm, I propose a conceptual revision founded upon the more inclusive concept of power. Power is a phenomenon where a dyadic relationship is asymmetrical (Simon 1953) and can be divided into two types: dominance and leverage. Dominance is power based upon the ability to use force. Leverage is power based upon a resource that cannot be taken by force. Four characteristics of power are used in sociology (base, means, amount, and scope) that facilitate both the expansion of the power concept beyond traditional dominance and the application of these theoretical ideas in empirical studies. This cross-disciplinary approach to power allows a wide range of behaviors to be considered as critical while at the same time it focuses the attention of researchers to the aspects of power that differ among dyads, classes, and species. Power is not simply a linear combination of dominance and leverage, and more research is needed before the exact nature of this relationship can be clarified. By considering dominance as one form of power, this framework fosters a more complete understanding of power dynamics and their effects on animal societies.

Animals↗