Waterfleas evolve in just a couple of generations

Waterfleas are known to evolve incredibly quickly in response to predation. In a new study from the University of Birmingham, researchers have taken a close look at 300 variable genes that make up roughly three percent of the waterflea genome. 

These variable genes seem to be the basis for life-saving changes in behavior and life history that come as a response to predators. The changes spread through a population very quickly – within only a couple of generations.

Rapid genetic changes are possible because of high genetic diversity that is already present in the population. 

“We were able to quantify the genetic diversity of one particular Daphnia population over nearly two decades and show clearly how rapid evolution took place in response to environmental pressures,” said lead researcher Dr. Anurag Chaturvedi.

“This type of research will be invaluable for understanding the potential impacts of future environmental changes on animal populations.”

The study highlights the importance of genetic diversity in a population of animals, and could translate into conservation decision making. Waterfleas themselves are important to the ecology of freshwater ponds as integral strands of the food web.  

The waterfleas were reared and exposed to fish, their genetics closely monitored to show changes to the genome in direct response to fish predation. 

Interestingly, the research showed that no more than five waterfleas from a regional set were required to supply enough genetic diversity to allow anti-predation evolutionary responses. These results show that genetic diversity in quickly evolving animals can be maintained at the landscape level, an important lesson for conservation biology.   

“Our ability to investigate populations that evolve across decades is invaluable for both fundamental and applied science discoveries,” said Dr. Chaturvedi.

The study is published in the journal Nature Communications. 

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By Zach Fitzner, Earth.com Staff Writer