REPRODUCTION IN FREE-RANGING MALE PROPITHECUS-VERREAUXI - THE HORMONAL CORRELATES OF MATING AND AGGRESSION

Endocrine studies of captive strepsirrhine primates suggest that physi cal environment and social factors mediate inter-individual variations in testicular function and serum testosterone (sT) in males. While th ese studies have made major contributions to our understanding of the individual proximate mechanisms influencing androgen activity in male strepsirrhines, none have investigated how these mechanisms work coinc identally in free-ranging populations. In this study we used fecal ste roid analysis to examine androgen-behavior interactions associated wit h reproduction in free-ranging male Propithecus verreauxi. Behavioral and hormone data were collected from two social groups during the 1990 - 91 and 1991 - 92 breeding seasons at Beta Mahafaly, Madagascar. Sol id phase and radioimmunoassay techniques were used to quantify testost erone (T) in 105 desiccated fecal samples collected weekly from seven males, Results suggest that 1) solid phase extraction and radioimmunoa ssay techniques were reliable and accurate methods for quantifying T i n sifaka feces; 2) fecal T (fT) elevations spanned a. minimum of 4 mon ths, peak levels occurring 1 month prior to the January onset of the b reeding season; 3) fecal T concentrations were influenced by developme ntal factors and, among mature males, social factors associated with r ank, intergroup aggression, and group instability. (C) 1998 Wiley-Liss , Inc.