caa a22 4500 465782566 CHVBK 20180323111959.0 cr unu---uuuuu 170327e19901201xx s 000 0 eng 10.1007/BF00164072 doi (NATIONALLICENCE)springer-10.1007/BF00164072 Perret Martine MNHN, CNRS URA 1183 Laboratoire d'Ecologie Générale, 4, Avenue du Petit Château, F-91800, Brunoy, France aut Influence of social factors on sex ratio at birth, maternal investment and young survival in a prosimian primate [Elektronische Daten] [Martine Perret] Summary: In order to determine whether social factors influence sex ratio at birth in lesser mouse lemurs, experiments were conducted during 5 successive breeding periods on 51 females. At the beginning of the breeding season, females were either isolated (I) or grouped (G) in heterosexual groups with an increasing number of females (2, 3 or 4). To ensure mating, I females were introduced in a group only during the oestrous period. After mating, both I and G females were isolated during pregnancy and lactation. Reproductive capacities of females in terms of oestrus occurrences (n = 324), impregnations (n−210), pregnancies (n = 136) or abortions (n = 38) or litter sizes (1-3 young) were affected neither by age and parity of females nor by group housing prior to conception. G females produced significantly more sons than daughters (67% males for 189 newborn) while females living alone except during the mating period demonstrated a significant inverse tendency (39.6% males for 96 newborn). Distribution of sexes in litters was statistically different from random and varied according to the shift of sex ratio at birth. In G females, the shift in the sex ratio towards males was consistent across the different groups, independent of the number of females living together, suggesting that the presence of only 1 female is sufficient to induce a bias in the sex ratio. No correlation was found between infant survival at weaning and age, parity or group housing of the mother. The maternal investment allocated to male or female newborn was similar provided the litter contained at least 1 male. In litters without males, growth and survival of female infants were significantly less. These results on sex ratio bias in captive female mouse lemurs agree with directions of bias predicted by the local resource competition model for facultative sex ratio adjustment (Clark 1978). Nevertheless, the pattern observed in mouse lemurs appears to be independent of the nutritional state of the female and of differential maternal investment. Springer-Verlag, 1990 Behavioral Ecology and Sociobiology Springer-Verlag 27/6(1990-12-01), 447-454 0340-5443 27:6<447 1990 27 265 https://doi.org/10.1007/BF00164072 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00164072 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Perret Martine MNHN, CNRS URA 1183 Laboratoire d'Ecologie Générale, 4, Avenue du Petit Château, F-91800, Brunoy, France aut NATIONALLICENCE 773 0- Behavioral Ecology and Sociobiology Springer-Verlag 27/6(1990-12-01), 447-454 0340-5443 27:6<447 1990 27 265 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer