Chemical Signal for Mate Selection

Friday 11 February 2011

Male Scents

This article demonstrates how a chemical signal and behaviour to use the signal might be affected by natural selection.  This could be used as one of the two examples in Option E1.4.

Gil Rosenthal, a biology professor at Texas A&M University has done research with swordtail fish and the chemicals in their urine.  How the male fish releases a pheromone in their urine to attract and stimulate female swordtail fish is an intriguing behaviour.  This behaviour indicates that the fish can control where and when they release the pheromone and the results suggest that the males are specifically targeting the time and place with females over without females.  The process of natural selection would favour such behaviour as those males which direct their sexual signals only when femailes are present would attract more females and be more likley to fertilize eggs with their sperm, thus passing on their genes for the pheromone as well as for the ability and behaviour to control the release of the chemicals.

Previous research has suggested that pheromone release was passive Reported in the journal Public Library of Science (PLoS) ONE, 

Swordtail adults captured in the wild from the Rio Atempa in Huitznopala, Mexico, were used to establish whether females were signaled by controlled use of pheromones or passive cues.  Rosenthal used  fluorescein dye to visualize urine release inside an aquarium, just as a pH indicator would show where an acidic substance appears. But this visualization process, he was able to ascertain that male fish released urine less frequently when no females were in the vicinity and more frequently when females were nearby. Thus indicating a link to courtship behaviour.  Of course in the wild, fish will behave differently.

In the streams, native males show courtship behaviour towards females in a similar manner but move upstream to allow their scent to be carried downstream towards the females.

“Our findings show that aquatic species and vertebrates, in particular, can have fine control over their release of chemical cues in the same manner as mammals that mark their territories or advertise their reproductive state, for example,” says Heidi Fisher, a former postdoctoral researcher in Rosenthal’s laboratory now at Harvard University.[1]

Swordtail fish have been frequently used as a model in animal communication as their sexual dimorphism and sterotpic behaviour allows for distinctive studies.

Why should investigating the chemical signals of swordtail urine be important?  To understanding how these fish and similar species communicate could be critical in knowing how natural populations behave. Additionally, the information could be used to show the health of the environment.  If pollutants were to disturb the chemical communication of reproduction, the change in population size would be an indicator of a problem.  This article could be useful in discussions about Option G4.1 Conservation of biodiversity which deals with the use of indicator species. 


Footnotes

  • 1. Jarvis, Chris. "Futurity.org – Fish turn it on to lure the girl." Futurity.org . N.p., n.d. Web. 20 Feb. 2011. <http://www.futurity.org/earth-environment/fish-turn-it-on-to-get-the-girl/>.

Tags: optionE, behaviour, selection