Differential Allocation Revisited: When Should Mate Quality Affect Parental Investment?

Abstract The differential allocation hypothesis predicts individuals will increase their reproductive investment when mated to a high quality partner. In many species of fish with biparental care females prefer large males due to the males’ greater ability to raise more offspring to independence. I examined the relationship between mate quality, parental care and number of offspring in a natural population of convict cichlids Amatitlania siquia. The frequency of frontal displays by females was positively correlated with male standard length. Additionally, as males increased in length relative to their mate, females increased the frequency of chases towards predators, while males decreased the number of displays towards brood predators. This trade-off in parental effort within a pair due to mate quality is a key prediction of differential allocation. The number of offspring was correlated with male, but not female, standard length. These results support the differential allocation hypothesis in that females offered more parental care to offspring of a larger male, while their mates decreased the amount of care they provided. Additionally, females benefited in terms of number of offspring by pairing with higher quality mates. Increased female investment may provide an incentive to ensure male care and maintain pair bonding, which could lead to greater reproductive success through increased offspring survival.

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Reproductive investment when mate quality varies: differential allocation versus reproductive compensation

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2008.0299 ◽

2009 ◽

Vol 364 (1520) ◽

pp. 1039-1048 ◽

Cited By ~ 91

Author(s):

W. Edwin Harris ◽

Tobias Uller

Keyword(s):

Evolutionary Dynamics ◽

Reproductive Investment ◽

Investment Strategy ◽

Specific Pattern ◽

Theoretical Treatment ◽

Male Quality ◽

Differential Allocation ◽

High Quality ◽

Mate Quality ◽

Reproductive Compensation

Reproductive investment decisions form an integral part of life-history biology. Selection frequently favours plasticity in investment that can generate maternal effects on offspring development. For example, if females differentially allocate resources based on mate attractiveness or quality, this can create a non-genetic link between mate attractiveness and offspring fitness with potential consequences for ecological and evolutionary dynamics. It is therefore important to understand under what conditions differential investment into offspring in relation to male quality is expected to occur and the direction of the effect. Two opposite predictions, increased investment into offspring produced with high-quality mates (differential allocation (DA)) and increased investment with low-quality males (reproductive compensation (RC)) have been suggested but no formal theoretical treatment justifying the assumptions underlying these two hypotheses has been conducted to date. Here, we used a state-based approach to investigate the circumstances under which the variation in mate quality results in differential female investment into offspring and how this interacts with female energetic resource levels. We found that a pattern of increased investment when mating with high-quality mates (i.e. DA) was the most common optimal investment strategy for females in our model. By contrast, increased investment when mating with low-quality mates (i.e. RC) was predicted only when the relative impact of parental investment on offspring quality was low. Finally, we found that the specific pattern of investment in relation to male quality depends on female energetic state, the likelihood for future mating opportunities and the expected future distribution of mate quality. Thus, the female's age and body condition should be important factors mediating DA and RC, which may help to explain the equivocal results of empirical studies.

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Parental investment, mate choice, and mate quality.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.74.8.3476 ◽

1977 ◽

Vol 74 (8) ◽

pp. 3476-3479 ◽

Cited By ~ 89

Author(s):

N. Burley

Keyword(s):

Mate Choice ◽

Parental Investment ◽

Mate Quality

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Adjustment of Parental Investment with Mate Quality by Male Yellow-Headed Blackbirds (Xanthocephalus xanthocephalus)

The Auk ◽

10.1093/auk/105.4.672 ◽

1988 ◽

Vol 105 (4) ◽

pp. 672-680 ◽

Cited By ~ 8

Author(s):

David F. Gori

Keyword(s):

Parental Investment ◽

Feeding Rate ◽

Male Reproductive Success ◽

Paternal Investment ◽

Parental Competence ◽

Mate Quality ◽

Male Preference ◽

Offspring Number ◽

Xanthocephalus Xanthocephalus ◽

Fledging Mass

Abstract By removing young from the nests of competent females, I tested whether male Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) could assess the parental competence of mates and adjust their parental investment accordingly. The purpose of this experimental reduction was to equalize the number of young in nests of parentally competent and incompetent females in order to control for the effect of offspring number on parental investment by males. Males had a greater probability of feeding at nests of competent-reduced females and they fed at a higher rate than they did at nests of incompetent females. The latter broods were fed only when nests belonging to competent females were unavailable. Males adjust their parental investment with mate quality independent of the number of young in nests. To explain this preference, I constructed functions to relate the amount of paternal investment (i.e. male feeding rate) to the number of young fledged from nests and the fledging mass of young. The latter are two components of male reproductive success and, therefore, estimates of the "return" on a male's parental investment. Male feeding had no effect on the number of young fledged from starvation-reduced or experimental nests. However, the fledging mass of young increased more when males helped competent females than when incompetent females were helped. Thus male preference for helping competent females may result because the return per unit of their investment is greater at these nests.

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