Dispersal by Propithecus verreauxi at Beza Mahafaly, Madagascar: 1984–1991

Abstract

From 1984 to 1991, 126 males and females were marked and monitored in a wild population of Propithecus verreauxi in southwest Madagascar. Animals were assigned birth years, based on known birth date or degree of dental wear calibrated by recapture data. Twenty‐one of 27 groups identified in 1984 persisted within stable home range boundaries, 6 groups disappeared, and 6 new groups formed. Only males transferred between existing groups, although individuals of both sexes left groups to form new groups. The home range of the group into which a male transferred usually overlapped that of his group of origin. On average, 35% of males aged 3–6 years transferred each year. Older males transferred at a lower rate. Three to 6‐year‐old males were more likely than older males to transfer two or three times. Most 3–6‐year old males transferred into groups with a higher proportion and number of females, whereas older males were progressively more likely to transfer into groups with a lower proportion and number of females. New groups were formed by older males, whose mates had died or who had not been successful in joining an existing group, and by young, nulliparous females. Males have rarely been observed for more than 5 years in the same group. Dispersal by 3–6‐year‐old males appeared to be voluntary. Females helped evict non‐natal males from the group but did not prevent new males from joining. Age at first reproduction was 5 years in this population. Forced secondary dispersal may occur when maturing females cease to tolerate males who may be their fathers. © 1993 Wiley‐Liss, Inc.

Birth season glucocorticoids are related to the presence of infants in sifaka ( Propithecus verreauxi )

“…Reproduction is seasonal in the wild with 96 per cent of births occurring during the late June to late August austral winter (Richard & Dewar 1991). In this species, males are the dispersing sex, most often leaving their natal group at 3 years of age, secondary and tertiary transfers representing the norm for this population (Richard et al 1993). Thirty-three per cent of adult males transfer annually, one-third of these transfers occurring during the birth season, resulting in as many as 60 per cent of groups undergoing a change in male membership at this time.…”

The lemur syndrome unresolved: extreme male reproductive skew in sifakas (Propithecus verreauxi), a sexually monomorphic primate with female dominance

“…Dispersal is strongly male-biased (Richard et al 1993), and males provide no paternal care apart from occasional infant grooming (Grieser 1992;Bastian and Brockman 2007). During their brief annual receptivity of about 1 day (range 30 min to 4 days; Brockman 1999), females, who dominate males (Richard and Nicoll 1987; see also , may mate with several males, sometimes including neighbors from adjacent groups or roaming males (Brockman and Whitten 1996;Brockman 1999).…”

Reproduction in free-rangingPropithecus verreauxi: Estrus and the relationship between multiple partner matings and fertilization

“…Alternatively, we propose that missed data and perinatal mortality are the best explanations for the absence of births reported for females 80 and 36. Sifaka at Beza Mahafaly have been censused annually since 1984, data being typically gathered toward the end of the birth season in August (Richard et al, 1991). Extrapolations from observations of mating and a 163-day gestation period (Petter-Rousseaux, 1962) indicate that female 80 and 36 would have delivered during the 4th week of June 1991 and the 3rd week of July 1992, respectively, 2-5 weeks before the onset of the census period.…”

“…Propithecus verreauxi a t Beza Mahafaly live in social groups ranging in size from two to 13 individuals, in which female philopatry and social dominance are the norm Richard and Nicoll, 1987;Richard et al, 1991). Sifaka a t this site have a 3-month breeding season beginning in January, during which most females experience single behavioral estrus periods (Brockman, 1994).…”