Quick Answer
Removing all mosquitoes would eliminate mosquito-borne transmission by mosquitoes, including malaria and many arboviruses, assuming no alternative vector replaced them. That would have enormous public-health benefits. Ecologically, however, mosquitoes occupy different roles across thousands of species, and the effects of removing them would vary by habitat and species rather than following one universal outcome.
Mosquito is a broad term covering thousands of species, and only a subset are major disease vectors. Males generally feed on plant sugars, while females of many species require blood meals to produce eggs. Their larvae also live in aquatic environments, where they become part of local food webs.
Disease transmission would collapse
If every mosquito vanished, diseases that depend on mosquitoes as vectors could no longer use them for transmission. Malaria would be among the most important examples, along with diseases such as dengue, yellow fever and several forms of encephalitis. The exact epidemiological outcome would depend on whether other vectors could replace mosquitoes for any particular pathogen.
Food webs would lose a link
Mosquito larvae and adults are eaten by fish, amphibians, spiders, birds and other organisms. Removing them would reduce one source of food, but ecosystems rarely depend on one species alone. Other insects and aquatic organisms could become more abundant and partly fill the gap.
Would plants suffer?
Some adult mosquitoes visit flowers and can contribute to pollination. However, their importance varies enormously by species and ecosystem. The disappearance of every mosquito would remove those interactions, but it would not remove pollination as a whole.
SpeculativeThere is no reliable single answer for how every ecosystem would respond to the loss of all mosquito species. Their ecological roles differ across regions, so some local food webs could change little while others could experience larger effects.
Could another insect take over?
Possibly. Ecological niches are often shared by multiple species. Removing mosquitoes could release resources and breeding sites that other insects exploit. Those replacements could themselves become more abundant and alter local disease or food-web dynamics.
The bottom line
The public-health effect of mosquito disappearance would be enormous because major mosquito-borne diseases would lose a crucial transmission route. The ecological result would be more variable: some systems would adapt through other insects and predators, while others could experience meaningful changes in aquatic and terrestrial food webs.
A note on our approach: Every article on WhatIfLab separates what current science establishes from what remains genuinely speculative. Where we cite a figure or finding, it reflects published, mainstream research at the time of writing — not a prediction dressed up as fact.