Invasive species are normally considered to come from outside a given ecosystem. But a study by researchers from the Indian Institute of Science Research and Education (IISER) Pune have shown that selection process for dispersal in fruit flies (Drosophila melanogaster) can lead to evolution of traits related to invasive potential. So a native species can become invasive in the same ecosystem.
Though the team led by Sutirth Dey from the Institute’s Biology Division did not specifically study for invasion potential of the flies, the experiments they conducted did show the flies acquiring increased aggression, exploration and activity, which together is more likely to make them more invasive.
In a study published in June 2017 in Oikos, the researchers subjected four populations, each containing about 2,400 flies, to artificial selection for increased dispersal over 33 generations. This was done by placing the flies in a bottle and connecting it to another using a long pipe. Only the first 50% of flies that moved to the second bottle were allowed to breed. Thus there was a direct selection for dispersal propensity — ability to leave the source area. And every 3-4 generations, the distance between bottles was increased by using a longer tube. This was done to mimic increased habitat fragmentation.
Source : https://www.thehindu.com/todays-paper/tp-features/tp-sci-tech-and-agri/iiser-pune-find-species-can-turn-invasive-in-the-same-ecosystem/article24606294.ece