A trade‐off between precopulatory and postcopulatory trait investment in male cetaceans

  title={A trade‐off between precopulatory and postcopulatory trait investment in male cetaceans},
  author={James P Dines and Sarah L. Mesnick and Katherine Ralls and Laura Johanna May-Collado and Ingi Agnarsson and Matthew D. Dean},
Mating with multiple partners is common across species, and understanding how individual males secure fertilization in the face of competition remains a fundamental goal of evolutionary biology. Game theory stipulates that males have a fixed budget for reproduction that can lead to a trade‐off between investment in precopulatory traits such as body size, armaments, and ornaments, and postcopulatory traits such as testis size and spermatogenic efficiency. Recent theoretical and empirical studies… 

No evidence for a trade‐off between sperm length and male premating weaponry

The relationship between precopulatory armaments and sperm length is evaluated in five taxa as well as meta‐analytically and there is no evidence for a negative or positive relationship between sperm length and male traits that are important in male–male contest competition.

Correlated evolution between targets of pre‐ and postcopulatory sexual selection across squamate reptiles

This evolutionary pattern suggests that strong precopulatory selection may often constrain the opportunity for postcopulatory selection and that the relative importance of each selective episode may determine the optimal resolution of energy allocation trade‐offs between traits subject to each form of sexual selection.

Population density and structure drive differential investment in pre‐ and postmating sexual traits in frogs

The intensifying struggle to monopolize fertilizations as more and more males clasp the same female to fertilize her eggs shifts male reproductive investment toward sperm production and away from male weaponry, explaining the trade‐off between pre‐ and postmating sexual traits in this much broader sample of anuran species.

Genetic variation but weak genetic covariation between pre‐ and post‐copulatory episodes of sexual selection in Drosophila melanogaster

Weak evidence is found for genetic correlations between precopulatory traits and indices of male fitness in Drosophila melanogaster, suggesting selection may act independently at the different episodes to maximize male reproductive success.

Sexual ornaments but not weapons trade off against testes size in primates

In a comparative study across primates, which exhibit considerable diversification in sexual ornamentation, male weaponry and testes size, it is found relative testesSize to decrease with sexual ornaments but increase with canine size.

Sperm competition and the coevolution of pre‐ and postcopulatory traits: Weapons evolve faster than testes among onthophagine dung beetles

The data for onthophagines support the notion that in taxa where males are unable to monopolize paternity, expenditure on both weapons and testes should both be favored.

Comparative morphological trade-offs between pre- and postcopulatory sexual selection in Giant hissing cockroaches (Tribe:

Evidence for a trade-off when investing in testes mass vs. horn length is found between two species of hissing cockroaches, supporting the predictions of pre- and postcopulatory competitive investment trade-offs for a relatively understudied Tribe ofcockroaches.

Sperm competition and the evolution of precopulatory weapons: Testis size and amplexus position, but not arm strength, affect fertilization success in a chorusing frog

This work focused on the factors affecting postcopulatory fertilization success during group spawning, using paternity data from natural choruses of the chorusing frog Crinia georgiana to offer within species empirical support for recent sperm competition models that incorporate precopulatory male–male competition.

Experimental manipulation reveals a trade‐off between weapons and testes

A sample of adult males from the same population in the wild revealed a positive correlation between investment in testes and weapons, and a critical contribution to a growing body of literature suggesting the allocation of resources to pre‐ and post‐copulatory sexual traits is influenced by a resource allocation trade‐off.

Lack of Evolution of Sexual Size Dimorphism in Heteromyidae (Rodentia): The Influence of Resource Defense and the Trade-Off between Pre- and Post-Copulatory Trait Investment

Insight is provided into the factors driving observed patterns of sexual dimorphism in this iconic group and the need to consider a broader framework beyond sexual selection for better understanding the evolution of dimorphic traits in this family is highlighted.



Expression of pre-and postcopulatory traits under different dietary conditions in guppies

The results reveal that diet manipulations influenced the expression of both precopulatory and postcopulatory sexually selected traits (sperm viability), reinforcing the importance of resource acquisition in sexual selection.

Do pre- and post-copulatory sexually selected traits covary in large herbivores?

Test the prediction that male’s weapon length covaries negatively with relative testes size and/or sperm dimensions across Artiodactyla using a phylogenetically controlled framework to propose several hypotheses that could explain why male ungulates may not balance their reproductive investment between pre- and post-copulatory traits.


It is shown that genital length appears to be positively associated with the strength of postcopulatory sexual selection, and both genital length and testes mass are negatively associated with investment in precopulatory weaponry, which is congruent with recent theoretical predictions of contest‐based sperm competition models.

Female monopolization mediates the relationship between pre- and postcopulatory sexual traits.

The prediction that the relationship between pre- and postcopulatory sexual traits differs among taxa relative to the importance of male-male contest competition within them is tested and is found to be correct.

Evolutionary trade-off between weapons and testes

A genus of horned beetle is used to examine the trade-off between investment in testes required for fertilizations and investment in weapons used to obtain matings, revealing a rich interplay between developmental trade-offs and both pre- and postmating mechanisms of sexual competition.


Data on testes allometry from two populations of O. taurus that have undergone genetic divergence in the frequency of minor males support the notion that the relative frequency of sneaks in the population influences male expenditure on the ejaculate.

Overt and covert competition in a promiscuous mammal: the importance of weaponry and testes size to male reproductive success

The Soay sheep mating system is characterized by male contests for mating opportunities and high female promiscuity and it is found that greater horn length, body size and good condition each independently influence a male' ability to monopolize receptive females.

Variation pattern of sperm quality traits in two gobies with alternative mating tactics

The pattern of variation that is found in the investment of sperm numbers and sperm quality in goby territorial and sneaker males, supports the results found in other species of fish with alternative mating tactics, suggesting that ejaculate quality traits are usually not traded off one against the other when ejaculate effort is increased in response to increased levels of sperm competition.

Trade‐offs during the Development of Primary and Secondary Sexual Traits in a Horned Beetle

The results suggest that even distant body parts may rely on a common resource pool to sustain their growth and that the relative timing of growth may play an important role in determining whether, and how severely, growing organs will affect each other during development.

Condition dependence of testis size in small mammals

It is suggested that males in good condition are capable of investing more in ejaculates than males in poor condition, and these results are consistent with the costly nature of ejaculate production.