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James Cheverud, Charles Hildebolt, Stephen Molnar, Jane Phillips-Conroy, Tab Rasmussen, Sondra Schlesinger, Richard Smith
Date of Award
Restricted Access Dissertation
Doctor of Philosophy (PhD)
Female primates incur higher reproductive costs than do males, and therefore social life may create greater levels of resource competition among females. The Lemuriformes show a high degree of maternal investment which may be exacerbated in the ringtailed lemur, Lemur catta, which inhabits the drier, more seasonal riverine forests of southern Madagascar. How ringtailed lemur females respond to such stresses depends on a number of ecological factors. At the forefront is the distribution and availability of resources, which in this study determined the expression of rank advantages, the value of intergroup resource defense, and reproductive seasonality. Reproductive events were tied to the availability of important resources. Thus females lactated and weaned their infants during a period of relative food abundance, but gestated during reduced food availability. Within each reproductive state females utilized numerous behaviors to reduce reproductive stresses. Rank-related feeding advantages were mediated by resource distribution. Only resources which were monopolizable showed clear rank effects. However, high rank may confer feeding advantages to adult offspring, who feed closer to their mothers and may therefore be buffered from feeding agonism. Intergroup encounters were intimately related to an increase or decrease in the availability of resources, with flowers and fruits being the most contested items. The habitat contained resources which showed predictable, seasonal variability in abundance, which may promote birth seasonality in this species. If reproductive costs are high enough, unusual forms of female-male relationships may occur. Within this context female dominance in ringtailed lemurs may preserve a polygamous social structure and all the advantages it confers, while limiting feeding competition received from males. Such effects should not be viewed as unique to only certain groups (i.e. the Lemuriformes), but rather as adaptations to a particular suite of ecological constraints.
Sauther, Michelle Linda, "The Effect of Reproductive State, Social Rank and Group Size on Resource Use Among Free-ranging Ringtailed Lemurs (Lemur catta) of Madagascar" (1992). Retrospective Theses and Dissertations. 58.