Effect of a Gravid Spot on Mate Choice

Drake Stockard, Brooke Hoover, Gabby Perez, Ragan Roth


Female fish have gravid spots on their underside that indicate she has reproduced before. We hypothesized that a female with a gravid spot would be more attractive than a female without because the male would know she is able to reproduce. We put two 3D printed female models (one with and without a gravid spot) in a tank with one live male guppy and observed the male’s behavior towards both females. To measure mate preference, we observed and logged courtship behaviors from the male guppy towards the female models. WE found that the fish with the gravid spot received more attention than the fish without. Therefore our hypothesis is supported by our data. However, Endler (2003) brings color into the discussion of mate selection that we did not account for, but was taken into consideration.

Full Text:



Abrahams, M. V. 1993. The trade-off between foraging and courting in males guppies. Animal Behaviour 45:673-681.

French, D. P. 2017. Research at the center for the Study of Sexual Selection in Fishes. Investigating Biology.

Endler, J. A. 2003, March 14. Variation in the appearance of guppy color patterns to guppies and their predators under visual conditions. Pergamon. http://www.sciencedirect.com/science/article/pii/004269899190109I

Norazmi- Lokman, N. H., G. J. Purser, J. G. Patil. 2016. Gravid Spot Predicts Developmental Progress and Reproductive Output in a Livebearing Fish, Gambusia holbrooki. PLOS One.

Orr, H. A. 2009. Fitness and its role in evolutionary genetics. Nature Reviews Genetics 10:531-539.

Richards, E. 2017. Darwin and the Making of Sexual Selection. Elsevier.


  • There are currently no refbacks.