Sexual dimorphism in sea lion pups: differential maternal investment, or sex-specific differences in energy allocation?

@article{Ono1996SexualDI,
  title={Sexual dimorphism in sea lion pups: differential maternal investment, or sex-specific differences in energy allocation?},
  author={Kathryn A. Ono and Daryl J. Boness},
  journal={Behavioral Ecology and Sociobiology},
  year={1996},
  volume={38},
  pages={31-41}
}
Abstract Proximal mechanisms underlying a faster growth rate in male compared to female California sea lion pups were investigated. Males are significantly larger at birth than females. Specifically, we asked if differential maternal investment contributed to enhanced male growth via: (1) larger mothers having disproportionately more male pups, (2) more time and energy put into foraging by mothers of male pups, and (3) greater milk production in mothers of male pups. We also considered four… Expand

Figures and Tables from this paper

Costly sons do not lead to adaptive sex ratio adjustment in pilot whales, Globicephala melas
TLDR
It was found that male calves grew faster than female calves during the first 5 years of life, suggesting that sons may require greater investment from lactating mothers, and that mothers may be constrained from biasing investment in the sexes, or that additional benefits may be masking such costs. Expand
Sons and daughters: age‐specific differences in parental rearing capacities
TLDR
These results suggest that sons are energetically more demanding on their parents than daughters, and the more expensive sex fledges in significantly poorer condition when the parents are young, and it is predicted that optimal offspring sex ratio will vary with parental age. Expand
Sex differences in mass loss rate and growth efficiency in Antarctic fur seal (Arctocephalus gazella) pups at Macquarie Island
TLDR
The results show that intersexual differences in growth rate may be accounted for by inter sexual differences in mass-specific rate of mass loss, because females lost 0.42% more of their total mass per day compared with male pups of the same body mass. Expand
Estimating expenditure on male and female offspring in a sexually size-dimorphic bird: a comparison of different methods.
TLDR
Comparisons of surrogate measures of parental investment in the brown songlark Cinclorhamphus cruralis reveal remarkable agreement between these estimates of investment and suggest that all may provide quantitatively useful information on sex allocation. Expand
Offspring sex ratio in the Common Tern Sterna hirundo, a species with negligible sexual size dimorphism
TLDR
Variation in offspring sex ratio in the Common Tern Sterna hirundo, a species with negligible sexual size dimorphism, is examined, finding that the sex ratio of c-eggs, but not of earlier laid eggs, was significantly biased in favour of females. Expand
Maternal investment in rhesus macaques (Macaca mulatta): reproductive costs and consequences of raising sons
TLDR
It is concluded that maternal investment is only slightly greater in sons than in daughters, with mothers endowing sons with extra resources because son, but not daughter, mass has ramifications for offspring sirehood. Expand
A trade-off between current and future sex allocation revealed by maternal energy budget in a small mammal
TLDR
This study attests a higher cost of sons, consequently leading to a lower investment in them, and reveals the significance of offspring sex in moulding the trade-off between current and future maternal investment. Expand
Sex-Specific Energetics of Pacific Walruses (Odobenus rosmarus divergens) during the Nursing Interval
TLDR
The energetics of 0–2-yr-old walrus calves are examined by using Bayesian hierarchical models based on longitudinal husbandry records of growth and caloric intake as a proxy for maternal lactation costs, which estimated total daily energy requirements were similar across sexes. Expand
Maternal investment in Antarctic fur seals: evidence for equality in the sexes?
TLDR
It is suggested that differential maternal expenditure does not occur in Antarctic fur seals because male pups probably do not gain greater benefit from additional maternal expenditure than female pups and the assumptions of the Trivers and Willard hypothesis are probably invalid for Antarctica fur seals. Expand
Male-biased investment in fallow deer: an experimental study
TLDR
The results indicate that male fallow deer fawns receive more milk from their mothers than female fawning under natural conditions and, hence, maternal investment seems male biased in this species. Expand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 50 REFERENCES
Maternal Energy Investment in Elephant Seal Pups: Evidence for Sexual Equality?
TLDR
Monitoring of northern elephant seal pups during the nursing period and throughout the postweaning fast found no evidence for sex differences in growth rate or milk intake rate, and mean metabolic rate of suckling pups did not differ significantly between the sexes. Expand
SEXUAL DIMORPHISM IN NEWBORN SOUTHERN SEA LIONS
TLDR
It is suggested that southern sea lion mothers invest more energy in sons than in daughters during gestation, a difference consistent with the importance of large body size to the reproductive success of males in a polygynous species. Expand
Mass changes of grey seal Halichoerus grypus pups on Sable Island: differential maternal investment reconsidered
TLDR
Little evidence of differential maternal investment is found in male and female grey seal pups during lactation and during the first 13 days of the postweaning fast using longitudinal data obtained on Sable Island, Canada. Expand
Parental investment in male and female offspring in polygynous mammals
TLDR
It is concluded that, in several mammals, mothers invest more heavily in individual sons than daughters but that, contrary to prediction, there is no indication that fewer male offspring are reared in these species. Expand
Behavioral and physiological measurements of maternal investment in the Steller sea lion, Eumetopias jubatus
TLDR
It is suggested that female attendance patterns are shaped by the increasing nutritional demands of growing pups and their increasing efficiency at suckling and that heavier pups consumed more milk than lighter ones. Expand
The Behavioral Ecology of Maternal Effort in Fur Seals and Sea Lions
TLDR
The flexibility of the rearing strategy of temperate and tropical species permits mothers to adjust phenotypically to variance in food availability thus partly masking the theoretically expected trade-offs in the life history of these species. Expand
Growth of grey seal (Halichoerus grypus) neonates: differential maternal investment in the sexes
TLDR
Estimated mean energy expenditure by females from conception to the time of weaning (maternal investment), including the heat increment of gestation, cost of foetal tissue, and energy contained in milk acquired during the nursing period, was greater for male than for female offspring. Expand
Milk and Energy Intakes of Suckling California Sea Lion Zalophus californianus Pups in Relation to Sex, Growth, and Predicted Maintenance Requirements
TLDR
The fact that California sea lion pups devote a large proportion of energy to maintenance rather than to growth or to blubber deposition may reflect both the energetic demands of an aquatic environment and limitations in the ability of lactating females to increase the rate of energy transfer to pups. Expand
Milk Intake of Elephant Seal Pups: An Index of Parental Investment
Total milk ingested throughout nursing in free-living northern elephant seal pups, derived from the turnover of tritiated water, gives an accurate estimate of the energetic component of parentalExpand
Maternal investment and neonatal growth in phocid seals
TLDR
Although data are limited, it appears that maternal investment differs between the sexes in all species which are sexually dimorphic with respect to body size. Expand
...
1
2
3
4
5
...