When a heat wave hits a city, public transit changes its schedule: fewer buses, but each one runs longer and breaks down less often. Mosquitoes reshuffle their lives in a similar way when things warm up around them. In the lab, Asian tiger mosquitoes were kept for three years at tropical temperatures: 32°C during the day and 26°C at night. Every five generations, the researchers measured how the insects were changing.
At first, the heat was a stressor for the mosquitoes: they lived shorter lives but rushed to leave offspring. By generation 10-15, everything had shifted. Females began living as long as their relatives in cooler conditions, but they laid fewer eggs. This new balance became fixed in their heredity. Males adapted more slowly than females, which means they are more sensitive to heat.
The key to survival turned out to be not the number of eggs, but how many larvae make it to adulthood. That is what determines how many females will be able to bite people and carry diseases. For cities where mosquitoes spread dengue and Zika, this is an important finding: forecasts need to account for the fact that mosquitoes evolve quickly, rather than simply adjusting to the heat temporarily.
The tropical mosquito lines produced only six generations per year instead of eight in the controls, even though up to thirteen are predicted in real tropics. This shows that laboratory heat does not fully mimic nature.
In Frank Herbert's novel Dune, the sandworms of Arrakis are adapted to extreme heat and dryness. This work shows that even ordinary mosquitoes can evolve quickly under a new climate, though not in a single generation.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.