Original Paper

Behavioral Ecology and Sociobiology

, Volume 64, Issue 11, pp 1849-1855

First online:

A novel, sexually selected trait in poeciliid fishes: female preference for mustache-like, rostral filaments in male Poecilia sphenops

  • Ingo SchluppAffiliated withDepartment of Zoology, University of OklahomaBiozentrum Grindel, University of Hamburg Email author 
  • , Rüdiger RieschAffiliated withDepartment of Zoology, University of Oklahoma
  • , Michael ToblerAffiliated withDepartments of Biology and Wildlife and Fisheries Sciences, Texas A&M University
  • , Martin PlathAffiliated withDepartment of Ecology and Evolution, J.W. Goethe University of Frankfurt
  • , Jakob ParzefallAffiliated withBiozentrum Grindel, University of Hamburg
  • , Manfred SchartlAffiliated withPhysiological Chemistry I, University of Würzburg

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Female choice can often drive the elaboration of male traits, leading to the evolution of secondary sexual traits. In the Mexican molly, Poecilia sphenops (Poeciliidae), some males exhibit a mustache-like structure on the upper maxilla, the function of which has not been previously recognized. The mustache consists of epidermal outgrowths at the edge of the scales that appear to have no sensory function. Trait expression varies within as well as among populations of P. sphenops, but is not linked to male body size polymorphism. In mate choice experiments, female P. sphenops exhibited a visual mating preference for males with mustaches, suggesting that the trait may be sexually selected. Since the mating behavior of P. sphenops involves contact of the male’s snout and the female genital region prior to copulation, we hypothesize that the mustache may also convey tactile signals to the female.


Mate choice Mating preference Sexual selection Structural ornaments