“Please settle a family argument- Is a mosquito a parasite?”

It’s complex and depends on how you define it! A straight answer may seem more satisfying, but there is more nuance to the answer. Believe it or not, but there are so many definitions of a “parasite.” I won’t go into them today, but there are quite a few.

If you’re to define that a parasite needs to live on its host, then a mosquito is not a parasite and is thus a predator that feeds on the blood of a host. This is the answer I’d go with. However, species of mosquitoes such as Aedes aegypti do carry pathogenic viruses (such as the yellow fever virus) which can be seen as parasites. These need a host to survive and reproduce. Further, something like the yellow fever virus can be thought of as a pathogen because it causes disease.

A good definition of a parasite is an organism which lives in or on another living organism, obtaining from its organic nutriment, usually having a negative influence on the fitness of its host, and commonly exhibiting some degree of adaptive modification (Price 1975).

Reference:

Price, P. W. (1975). Introduction: The parasitic way of life and its consequences. In Evolutionary strategies of parasitic insects and mites (pp. 1-13). Springer, Boston, MA.