Answer:Natural selection
Explanation:Natural selection is a concept based on Darwin's theory of evolution, according to this theory organisms who can best adapt to their ever changing environment are likely to survive and pass their strong genetic characters to the next generation. Those organism that finds it hard to adapt get eliminated and their characteristics dies out .
This is the reason we see an increased population of 4.1mm average wingspan mosquitoes whilst initially the population had 6.5 mm average wingspan.
"Small size enables greater chances of survival facing these predators"