Featured Image Credit: Gina Ferazzi / Los Angeles Times
By: Jessica Kittel
Pupfish were named after puppies due to their playful nature, which has to be one of the cutest justifications ever for the naming a fish species. Just look at them, they just scream, “I’m adorable!” They’re more than just a cute face though, they’re The Flash of the fish evolution world.
Pupfish have been known to survive in rather extreme locations and conditions. The Devil’s Hole pupfish, for example, can only survive in a particular underground cavern in the middle of Death Valley, Nevada. The water these fish inhabit is 89 degrees Fahrenheit on average, a temperature that most fish would probably find rather uncomfortable, oh, and deadly.
Pupfish are also known for being super fast evolutionizers (please note: that is not a real word, it was made up strictly for the purpose of this sentence). In science (and not made up) terms, they’re pretty impressive at adaptive diversification. Pupfish display the fastest morphological diversification rates in fishes. Certain pupfish groups are evolving 50-130 times more quickly than any other pupfish species. All of this means that these pupfishes are displaying the evolution of novel ecological niches.
The evolution of ecological niches is essentially when a species or group evolves to fill a new or available niche. A niche is the area, role, or position an organism has in its environment. For example, let’s say I could take or leave avocados but I move to a town where everyone violently hates avocados and won’t even consider eating them even though there’s a whole grove of avocado trees smack dab in the middle of the town. If I eat the avocados, I’m filling that open niche of food availability. This is super beneficial to me because now I have a never-ending food supply that I don’t have to share with anyone except perhaps my children who will probably inherit my affinity for avocados.
Pupfish have done something very similar in a lake located on San Salvador Island in the Bahamas. Over the years, the pupfish living in the salty inland lakes were able to diversify into multiple species, all with different dietary preferences. One species eats the scales of other fish, another species feeds on snails and ostracods, and the third eats algae (like a normal pupfish). These fish aren’t competing for food and can comfortably survive in their own niche.
New research suggests that this diversification was made possible by the contribution of multiple outside sources of genetic information in the form of other species of pupfish from surrounding areas. This research also suggests that, in order for adaptive radiation to occur, multiple factors (such as breeding with related species and new ecological opportunities) have to work in conjunction.
Now if only there was a pupfish that liked avocados…