Reproductive factors affecting survivorship in captive callitrichidae

Abstract

Efforts to breed Callitrichidae in captivity have resulted in high fertility accompanied by high infant mortality. This paper investigates the relationship between reproductive characteristics and survivorship in the Oak Ridge and Associated Universities (ORAU) callitrichid colony. Records of 2,834 individuals were analyzed using Cox Proportional Hazards regression to investigate factors affecting infant survivorship. Species and birth cohort were found to have a significant (P less than 0.05) effect on survivorship. Litter size also was an important factor in determining survivorship. Individuals born into singlet and twin litters had significantly (P less than 0.001) higher survivorship than triplets. Factors which affect survivorship perinatally (0-1 months of age), prior to breeding age and subsequent to the first month of life were then investigated. Litter size was a significant (P less than 0.05) factor in determining survivorship perinatally, with twins having significantly higher survivorship than both singlets and triplets. After the first month of life, litter size no longer showed a significant effect on survivorship. Records of 145 dams were analyzed using the same procedures to investigate reproductive characteristics associated with survivorship. Age at first litter showed a significant (P less than 0.01) positive relationship with dam survivorship. These results suggest various factors affect survivorship at specific temporal points during development, and also suggest selection for survivorship perinatally to be strongly associated with litter size, possibly through sibling competition and maternal effects.

Interactions between infant growth and survival: Evidence for selection on age-specific body weight in captive common marmosets (Callithrix jacchus)

“…This result is in agreement with results from other captive colonies of callitrichids [Kilbourn et al, 1983;Kirkwood et al, 1983;Rothe et al, 1992] and a previous study of the ORAU colony [Jaquish et al, 1991]. The results indicate that very early infancy is a critical period for infant survival in marmosets, as it is for many mammalian species [Cameron, 1973;Cheney et al, 1988;Le Boeuf & Reiter, 1988;Packer et al, 1988].…”

“…A similar inverse relationship between twins and triplets has been found in captive marmosets and tamarins [Jaquish et al, 1991;Kilbourn et al, 1983;Kirkwood et al, 1983]. However, the same relationship is not found when comparing survival of twins and singletons [Jaquish et al, 1991]. Hearn and Burden [1979] have found that survivorship of triplet litters of common marmosets is greatly increased if one triplet is cared for by hand periodically.…”

“…This additional analysis was performed to disentangle the possible confounding effects of weight and litter size. Directional hypotheses regarding the effect of the covariates on survival were formed based on a previous study of this colony and the assumption that larger infants would have better survival [Jaquish et al, 1991;Jaquish, 1993]. Therefore, one-tailed significance tests were used throughout the analysis.…”

“…Many mammalian species show high mortality prior to weaning as compared to other life stages [Cameron, 1973;Cheney et al, 1988;Jaquish et al, 1991;Le Boeuf & Reiter, 1988;Packer et al, 1988;Rothe et al, 1992]. Many factors can affect infant survival, among them population density, availability of food, season of birth, infant birth weight, litter size, and the social environment.…”

Reproductive skew in female common marmosets: what can proximate mechanisms tell us about ultimate causes?

“…Therefore, selection should favour females that can detect circumstances highly inauspicious for reproduction-such as the presence of a potentially infanticidal dominant female-and restrain their own reproductive activity under these conditions. By engaging specialized, inhibitory neuroendocrine and behavioural mechanisms in the presence of a dominant female, subordinates minimize their own likelihood of investing in costly reproductive attempts that are unlikely to succeed, possibly increasing their prospects for survival and successful reproduction in the future ( Wasser & Barash 1983;Jaquish et al 1991;Digby 1995a;Abbott et al 1997;Saltzman 2003;Gilchrist 2006). …”