High male sexual investment as a driver of extinction in fossil ostracods

  title={High male sexual investment as a driver of extinction in fossil ostracods},
  author={M J F Martins and Terry Markham Puckett and Rowan Lockwood and John P. Swaddle and Gene Hunt},
Sexual selection favours traits that confer advantages in the competition for mates. In many cases, such traits are costly to produce and maintain, because the costs help to enforce the honesty of these signals and cues1. Some evolutionary models predict that sexual selection also produces costs at the population level, which could limit the ability of populations to adapt to changing conditions and thus increase the risk of extinction2–4. Other models, however, suggest that sexual selection… 
Shifts in sexual dimorphism across a mass extinction in ostracods: implications for sexual selection as a factor in extinction risk
It is suggested that sexual selection and the allocation of resources towards survival versus reproduction may be an important factor for species extinction during both background and mass extinctions.
Sexual selection predicts the persistence of populations within altered environments.
It is found that both horn presence and relative size are strongly positively associated with species persistence and abundance in altered habitats, and this study represents the first evidence from a field system of a population-level benefit from pre-copulatory sexual selection.
Male‐biased sexual selection, but not sexual dichromatism, predicts speciation in birds
The findings support the view that male‐biased sexual selection, as measured by frequent predictors of male‐male competition, has shaped diversification in the largest radiation of birds.
Sexual selection, environmental robustness, and evolutionary demography of maladapted populations: A test using experimental evolution in seed beetles
Seed beetles evolved under three alternative mating regimes to disentangle the contributions of sexual selection, fecundity selection, and male–female coevolution to individual reproductive success and population fitness and found evidence that sexual selection on males had positive genetic effects on female fitness components across environments, supporting good‐genes sexual selection.
Sexual selection, environmental robustness and evolutionary demography of maladapted populations: a test using experimental evolution in seed beetles
Seed beetles evolved under three alternative mating regimes to disentangle the contributions of sexual selection, fecundity selection and male-female coevolution to individual reproductive success and population fitness and suggest that sex-specific selection can cause differences in environmental robustness that may impact population demography under environmental change.
Sexual signals persist over deep time: ancient co-option of bioluminescence for courtship displays in cypridinid ostracods
The persistence of luminous courtship for hundreds of millions of years indicates that rates of speciation within the group exceeded extinction risk, allowing for the persistence of a diverse clade of signalling species and that sexual selection did not cause rapid loss of associated traits.
Experimental evidence for effects of sexual selection on condition-dependent mutation rates
It is shown that sexual selection and the generation of new genetic variation via mutation may be entangled in an evolutionary feedback loop, offering causality to the widely observed male mutation bias and implications for the maintenance of genetic variation in fitness.
Larger offspring associated with lower temperatures across species of Microporella, a widespread colonial invertebrate
It is found that offspring size is affected by a combination of module size and water temperature (or latitude when fossil species are included), while fecundity and levels of nutrients have a weak to no effect on this life history trait.
Sexual Dichromatism Is Decoupled from Diversification over Deep Time in Fishes
It is shown how the effects of dichromatism on diversification are highly variable in direction and restricted to certain clades and phylogenetic scales.
Do sexually selected weapons drive diversification?
The results suggest that precopulatory male-male competition may not have strong, general effects on speciation and diversification in insects, a group encompassing ∼60% of all described species.


Sexy to die for? Sexual selection and the risk of extinction
It is argued that evolutionary 'suicide' - as sometimes suggested - is unlikely in deterministic environments, except if costs are not paid by the same individual that bears the trait, and shows an example where greater mortality of males due to sexual dimorphism improves the carrying capacity of the environment, and thus presumably population viability.
Correlation between investment in sexual traits and valve sexual dimorphism in Cyprideis species (Ostracoda)
The correlation between the hemipenis parts, especially basal capsule size and male valve sizeDimorphism suggests that sexual selection on sperm size, quantity, and/or efficiency of transfer may drive sexual size dimorphism in these species, although it cannot exclude other aspects of sexual and natural selection.
Will their armaments be their downfall? Large horn size increases extinction risk in bovids
It is shown that the threat level of bovid species increases with large male horn size, the first time, to my knowledge, that sexually selected weaponry has been shown to increase extinction risk at the interspecific level.
Sexual selection affects local extinction and turnover in bird communities
It is found that sexual selection increased risks of local extinction (dichromatic birds had on average a 23% higher local extinction rate than monochromatic species), and Anthropogenic factors impeding dispersal might have a significant impact on the global persistence of sexually selected species.
Sexual selection and the risk of extinction in mammals
  • E. H. Morrow, C. Fricke
  • Biology, Psychology
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 2004
This study examined whether the level of sexual selection (measured as residual testes mass and sexual size dimorphism) was related to the risk of extinction that mammals are currently experiencing, and found no evidence for a relationship between these factors.
Sexual selection protects against extinction
Comparing whether populations with histories of strong versus weak sexual selection purge mutation load and resist extinction differently is compared, revealing mutation load using inbreeding.
How sexual selection can drive the evolution of costly sperm ornamentation
The results suggest that producing few gigantic sperm evolved by Fisherian runaway selection mediated by genetic correlations between sperm length, the female preference for long sperm and female mating frequency, and longer sperm increasing the indirect benefits to females and the developmental integration of sperm quality and quantity renders post-copulatory sexual selection on ejaculates unlikely to treat male–male competition and female choice as discrete processes.
Sexual selection hinders adaptation in experimental populations of yeast
It is found that populations experiencing stronger sexual selection are less able to adapt to a novel environment compared with populations experiencing weaker sexual selection or no sex, and that strong sexual selection erases the benefits of sexual reproduction.
Sexual selection can both increase and decrease extinction probability: reconciling demographic and evolutionary factors
It is found that sexual selection can lead to both increases and decreases in population-level fitness measures such as extinction probability and adaptation rate, and this is consistent with field studies that have mostly focussed on very small populations, and tend to find negative effects, and with laboratory studies that tend to use larger populations and have tended to find positive effects.
The cost of reproduction and sexual selection
The examples presented show that the cost of sexual selection could be mediated in many ways and it is suggested that future studies should focus on such mechanisms.