Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

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


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 extinction2,3,4. Other models, however, suggest that sexual selection should increase rates of adaptation and enhance the removal of deleterious mutations, thus protecting populations against extinction3, 5, 6. Resolving the conflict between these models is not only important for explaining the history of biodiversity, but also relevant to understanding the mechanisms of the current biodiversity crisis. Previous attempts to test the conflicting predictions produced by these models have been limited to extant species and have thus relied on indirect proxies for species extinction. Here we use the informative fossil record of cytheroid ostracods—small, bivalved crustaceans with sexually dimorphic carapaces—to test how sexual selection relates to actual species extinction. We show that species with more pronounced sexual dimorphism, indicating the highest levels of male investment in reproduction, had estimated extinction rates that were ten times higher than those of the species with the lowest investment. These results indicate that sexual selection can be a substantial risk factor for extinction.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Sexual dimorphism in two species of cytheroid ostracods.
Fig. 2: Model-predicted extinction rate according to sexual size and shape dimorphism.


  1. Höglund, J. & Sheldon, B. C. The cost of reproduction and sexual selection. Oikos 83, 478–483 (1998).

    Article  Google Scholar 

  2. Lande, R. Sexual dimorphism, sexual selection, and adaptation in polygenic characters. Evolution 34, 292–305 (1980).

    Article  Google Scholar 

  3. Kokko, H. & Brooks, R. Sexy to die for? Sexual selection and the risk of extinction. Ann. Zool. Fenn. 40, 207–219 (2003).

    Google Scholar 

  4. Tanaka, Y. Sexual selection enhances population extinction in a changing environment. J. Theor. Biol. 180, 197–206 (1996).

    Article  CAS  Google Scholar 

  5. Lumley, A. J. et al. Sexual selection protects against extinction. Nature 522, 470–473 (2015).

    Article  ADS  CAS  Google Scholar 

  6. Lorch, P. D., Proulx, S., Rowe, L. & Day, T. Condition-dependent sexual selection can accelerate adaptation. Evol. Ecol. Res. 5, 867–881 (2003).

    Google Scholar 

  7. Darwin, C. The Descent of Man, and Selection in Relation to Sex. (John Murray, London, 1871).

    Book  Google Scholar 

  8. Andersson, M. Sexual Selection. (Princeton Univ. Press, Princeton, 1994).

    Google Scholar 

  9. Martínez-Ruiz, C. & Knell, R. J. Sexual selection can both increase and decrease extinction probability: reconciling demographic and evolutionary factors. J. Anim. Ecol. 86, 117–127 (2017).

    Article  Google Scholar 

  10. Jacomb, F., Marsh, J. & Holman, L. Sexual selection expedites the evolution of pesticide resistance. Evolution 70, 2746–2751 (2016).

    Article  Google Scholar 

  11. Reding, L. P., Swaddle, J. P. & Murphy, H. A. Sexual selection hinders adaptation in experimental populations of yeast. Biol. Lett. 9, 20121202 (2013).

    Article  CAS  Google Scholar 

  12. Doherty, P. F. Jr et al. Sexual selection affects local extinction and turnover in bird communities. Proc. Natl Acad. Sci. USA 100, 5858–5862 (2003).

    Article  ADS  CAS  Google Scholar 

  13. Bro-Jørgensen, J. Will their armaments be their downfall? Large horn size increases extinction risk in bovids. Anim. Conserv. 17, 80–87 (2014).

    Article  Google Scholar 

  14. Sorci, G., Møller, A. P. & Clobert, J. Plumage dichromatism of birds predicts introduction success in New Zealand. J. Anim. Ecol. 67, 263–269 (1998).

    Article  Google Scholar 

  15. McLain, D. K., Moulton, M. P. & Sanderson, J. G. Sexual selection and extinction: the fate of plumage-dimorphic and plumage-monomorphic birds introduced onto islands. Evol. Ecol. Res. 1, 549–565 (1999).

    Google Scholar 

  16. Morrow, E. H. & Fricke, C. Sexual selection and the risk of extinction in mammals. Proc. R. Soc. B 271, 2395–2401 (2004).

    Article  Google Scholar 

  17. Prinzing, A., Brändle, M., Pfeifer, R. & Brandl, R. Does sexual selection influence population trends in European birds? Evol. Ecol. Res. 4, 49–60 (2002).

    Google Scholar 

  18. Thomas, G. H., Lanctot, R. B. & Székely, T. Can intrinsic factors explain population declines in North American breeding shorebirds? A comparative analysis. Anim. Conserv. 9, 252–258 (2006).

    Article  Google Scholar 

  19. McLain, D. K., Moulton, M. P. & Redfearn, T. P. Sexual selection and the risk of extinction of introduced birds on oceanic islands. Oikos 74, 27–34 (1995).

    Article  Google Scholar 

  20. Payne, J. L. et al. Extinction intensity, selectivity and their combined macroevolutionary influence in the fossil record. Biol. Lett. 12, 20160202 (2016).

    Article  Google Scholar 

  21. Orzechowski, E. A. et al. Marine extinction risk shaped by trait–environment interactions over 500 million years. Glob. Change Biol. 21, 3595–3607 (2015).

    Article  ADS  Google Scholar 

  22. Knell, R. J., Naish, D., Tomkins, J. L. & Hone, D. W. E. Sexual selection in prehistoric animals: detection and implications. Trends Ecol. Evol. 28, 38–47 (2013).

    Article  Google Scholar 

  23. Cohen, A. C. & Morin, J. G. Patterns of reproduction in ostracodes: a review. J. Crustac. Biol. 10, 184–212 (1990).

    Google Scholar 

  24. Martins, M. J. F., Hunt, G., Lockwood, R., Swaddle, J. P. & Horne, D. J. Correlation between investment in sexual traits and valve sexual dimorphism in Cyprideis species (Ostracoda). PLoS ONE 12, e0177791 (2017).

    Article  Google Scholar 

  25. Kamiya, T. Heterochronic dimorphism of Loxoconcha uranouchiensis (Ostracoda) and its implications for speciation. Paleobiology 18, 221–236 (1992).

    Article  Google Scholar 

  26. Hunt, G. et al. Sexual dimorphism and sexual selection in cytheroidean ostracodes from the Late Cretaceous of the U.S. coastal plain. Paleobiology 43, 620–641 (2017).

    Article  Google Scholar 

  27. Puckett, T. M. Santonian–Maastrichtian planktonic foraminiferal and ostracode biostratigraphy of the northern Gulf Coastal Plain, USA. Stratigraphy 2, 117–146 (2005).

    Google Scholar 

  28. Liow, L. H. & Nichols, J. D. in Quantitative Methods in Paleobiology The Paleontological Society Papers Vol. 16 (eds Alroy, J. & Hunt, G.) 81–94 (The Paleontological Society, New Haven, 2010).

  29. Burnham, K. P. & Anderson, D. R. Model Selection and Multimodel Inference. 2nd edn, (Springer, New York, 2010).

    MATH  Google Scholar 

  30. Servedio, M. R. & Boughman, J. W. The role of sexual selection in local adaptation and speciation. Annu. Rev. Ecol. Evol. Syst. 48, 85–109 (2017).

    Article  Google Scholar 

  31. Horne, D. J., Danielopol, D. L. & Martens, K. in Sex and Parthenogenesis. Evolutionary Ecology of Reproductive Modes in Non-marine Ostracods (ed. Martens, K.) 157–195 (Backhuys Publishers, Leiden, 1998).

  32. Lüpold, S. et al. How sexual selection can drive the evolution of costly sperm ornamentation. Nature 533, 535–538 (2016).

    Article  ADS  Google Scholar 

  33. Chapman, T., Liddle, L. F., Kalb, J. M., Wolfner, M. F. & Partridge, L. Cost of mating in Drosophila melanogaster females is mediated by male accessory gland products. Nature 373, 241–244 (1995).

    Article  ADS  CAS  Google Scholar 

  34. Stanley, S. M. An analysis of the history of marine animal diversity. Paleobiology 33, 1–55 (2007).

    Google Scholar 

  35. Holland, S. M. The stratigraphic distribution of fossils. Paleobiology 21, 92–109 (1995).

    Article  Google Scholar 

  36. Payne, J. L., Bush, A. M., Heim, N. A., Knope, M. L. & McCauley, D. J. Ecological selectivity of the emerging mass extinction in the oceans. Science 353, 1284–1286 (2016).

    Article  ADS  CAS  Google Scholar 

  37. Larina, E. et al. Upper Maastrichtian ammonite biostratigraphy of the Gulf Coastal Plain (Mississippi Embayment, southern USA). Cretac. Res. 60, 128–151 (2016).

    Article  Google Scholar 

  38. White, G. C. & Burnham, K. P. Program MARK: survival estimation from populations of marked animals. Bird Study 46, S120–S139 (1999).

    Article  Google Scholar 

  39. Laake, J. L. RMark: An R Interface for Analysis of Capture-Recapture Data with MARK. AFSC Processed Report No. 2013-01 (Alaska Fisheries Science Center, 2013).

  40. Liow, L. H. & Finarelli, J. A. A dynamic global equilibrium in carnivoran diversification over 20 million years. Proc. R. Soc. B 281, 20132312 (2014).

    Article  Google Scholar 

  41. Foote, M. et al. Rise and fall of species occupancy in Cenozoic fossil mollusks. Science 318, 1131–1134 (2007).

    Article  ADS  MathSciNet  CAS  Google Scholar 

  42. Raup, D. M. Mathematical models of cladogenesis. Paleobiology 11, 42–52 (1985).

    Article  Google Scholar 

Download references


We thank L. Smith (LSU) and C. Sanford (NMNH) for help with access to museum specimens and C. Hall, C. Sweeney, J. Shaw, and J. Stedman for assistance in data collection. This research was supported by NSF-EAR 1424906 and the National Museum of Natural History, Smithsonian Institution.

Reviewer information

Nature thanks M. Gage, R. Knell and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information

Authors and Affiliations



G.H. and M.J.F.M. collected the sexual dimorphism data and performed the analyses; T.M.P. collected the stratigraphic data and helped with the collection of dimorphism data. R.L., J.P.S. and G.H. designed the project and M.J.F.M. and G.H. primarily wrote the paper.

Corresponding author

Correspondence to Gene Hunt.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended Data Fig. 1 Stratigraphic section showing the occurrence of 93 species over time.

a, Location map of Tennessee, Mississippi and Alabama. The locations of samples that were collected from the focal composite reference section in Mississippi (MSCRS, blue circles) and the composite section in Alabama, which were treated as a replicate (ALCRS, red triangles), are shown along with the additional samples in the database that were used to compute occupancy (crosses). b, Stratigraphic occurrences for the MSCRS are shown. Each grey circle represents the occurrence of a species in a sample, with each species labelled according to four-letter abbreviations given in Supplementary Table 4. The map was made using the R package ‘maps’.

Extended Data Fig. 2 Estimated model coefficients relating sexual size and shape dimorphism to extinction.

a, Sexual size dimorphism (DMsize). b, Shape dimorphism (DMshape). The best 40 models are shown, sorted in order of decreasing support. The model-averaged coefficients are shown on the far right as larger circles. These estimates integrate over all models, weighted by their support, appropriately accounting for uncertainty in model selection. Error bars are 95% confidence intervals generated by MARK software.

Extended Data Fig. 3 Stratigraphic occurrences of species plotted with respect to shape dimorphism.

Top, species in the family Trachyleberididae; bottom, all other species. Species are sorted left to right based on shape dimorphism, with more extreme dimorphism plotted towards the right and in warmer colours. Symbol size is proportional to occupancy (larger indicates more broadly distributed). In the Trachyleberididae, there is a clear visual indication that more strongly dimorphic species have shorter stratigraphic durations.

Extended Data Table 1 Best supported models for extinction and speciation using occurrence data from a replicate reference section in central Alabama

Supplementary information

Supplementary Table 1

Excel spreadsheet with model support information for all 576 models.

Reporting Summary

Supplementary Table 2

Species attributes used in the analysis: dimorphism, shape dimorphism, occupancy, and family membership. Used by the CMR script.

Supplementary Table 3

Sample attributes used in the analysis: sample abundance (total number of ostracodes), formation/member name, minimum and maximum sample age (in Ma). Used by the CMR script

Supplementary Table 4

List of species analyzed, including their assignment to taxonomic family and the four-letter code used in Extended Data Figure 1

Supplementary Data

This file contains an R script that runs the CMR analysis presented in Table 1

Supplementary Data

This file contains a MARK input file format with species occurrences by sample. Used by the CMR script

Rights and permissions

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Martins, M.J.F., Puckett, T.M., Lockwood, R. et al. High male sexual investment as a driver of extinction in fossil ostracods. Nature 556, 366–369 (2018).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing