A team of biologists from the Catholic University of Leuven, in Belgium, has discovered that water fleas, tiny crustaceans included in the suborder cladocerans, have genetically adapted to climate change . To determine this, these researchers have compared “revived” specimens of eggs that have been preserved for 40 years and more recent specimens. According to Professor Luc De Meester, from the Aquatic Ecology Laboratory of the aforementioned institution, which has coordinated the trial, water fleas usually reproduce asexually under normal conditions; in essence, they clone themselves. However, when food is scarce or temperatures rise, they mate and leave their embryos encapsulated in egg-like structures so that they can remain safely in sediment for decades.
“When they reproduce in the first way, the offspring of the water fleas are genetically identical to the parent, but if they mate there are variations in the DNA,” explains De Meester. “After, so to speak, bringing the embryos that have remained dormant in recent years back to life and comparing them with current populations, we have been able to reconstruct the evolutionary changes that have occurred in the latter and study how they have adapted to the increase in temperatures that the environment has experienced ”, he indicates.
De Meester’s team subjected the water fleas to various tests, including significant temperature changes in their environment, up to 4 ° C. Thus, these experts were able to determine that these organisms can adapt to thermal rises , something that, however, does not guarantee their survival, since environmental changes also lead to greater exposure to parasites and predators.
