Environmental Biology of Fishes

, Volume 90, Issue 2, pp 197–205

Feeding efficiency and food competition in coexisting sexual and asexual livebearing fishes of the genus Poecilia

  • Kristin Scharnweber
  • Martin Plath
  • Michael Tobler

DOI: 10.1007/s10641-010-9732-8

Cite this article as:
Scharnweber, K., Plath, M. & Tobler, M. Environ Biol Fish (2011) 90: 197. doi:10.1007/s10641-010-9732-8


Considering its immediate costs of producing dispensable males, the maintenance of sexual reproduction is a major paradox in evolutionary biology. Asexual lineages that do not face such costs theoretically should replace sexuals over time. Nonetheless, several systems are known in which closely related sexual and asexual lineages stably coexist. In the present study, we studied a sexual/asexual mating complex of a sperm-dependent parthenogenetic fish (amazon molly, Poecilia formosa) and its sexual congeners, the sailfin molly P. latipinna and the Atlantic molly P. mexicana. We asked whether differences in feeding behavior could contribute to their stable coexistence. We conducted a laboratory experiment to compare feeding efficiencies and also measured the competitive abilities between the two reproductive forms. Additionally, we measured gut fullness of fishes caught in natural habitats. Contrary to our predictions, we could not find P. formosa to be less efficient in feeding. We argue that food competition in mollies plays a minor role in mediating coexistence between closely related asexual and sexual mollies.


Aggressive interactions Competition Evolution of sex Foraging Gynogenesis 

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Kristin Scharnweber
    • 1
  • Martin Plath
    • 2
  • Michael Tobler
    • 3
    • 4
  1. 1.Department of Biology and Ecology of FishesLeibniz Institute of Freshwater Ecology & Inland FisheriesBerlinGermany
  2. 2.Department of Ecology and Evolution, Institute of Ecology, Evolution and DiversityJ.W. Goethe University FrankfurtFrankfurt am MainGermany
  3. 3.Department of Wildlife and Fisheries SciencesTexas A&M UniversityCollege StationUSA
  4. 4.Department of ZoologyOklahoma State UniversityStillwaterUSA

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