It depends on situation, in which you are working and on the problem you study. Any correctly interpreted biological data have significance for bio-indication. Each species bears somewhat other information and indicates something other. The degree, to which we are able to use it for bioindication depends,  on out knowledge on autecology of respective species. iIt needs, of course, a good field experience and rich data (if possible own) for comparison. In addition, it is to be takes in acount that the species response on environmental factors vary within their distribution area, Therefore the data from literature are to be taken with certain criticism.

In the "exotic" countries (from aur superficial few of Central Europe) the situatiuon is difficult because many species are little known, some can be even new for the science.

So to use the "exotic" species for bioindication is, in certain sense, a pioneer work. 

I agree on the usefulness of utilizing mosquitoes as bioindicators, but as Dr. Sustek told, they need to be very well studied, before utilizing them. There are also variations on the biology according to the species in the group, as exemplified by Limatus durhamii, supposedly a sylvatic mosquito, like other sabethine, which can adapt to artificial breeding places. In Culex and Aedes, there are sylvatic and domiciliated species.

Culex mosquitoes adapt to polluted environment and are the most common species usually found in such places. In rare cases however, it may be possible to find Anopheles mosquitoes breeding in water bodies with moderate or high level of pollution as evident in this publication- Awolola et. al., (2007) Anopheles gambiae s.s. breeding in polluted water bodies in urban Lagos, southwestern Nigeria. Journal of vector borne diseases 44(4):241-4.

I too agree with the fact that Culex mosquitoes are very well adapted to different environmental conditions. anopheles mosquitoes too are found at varying locations but comapartively Culex are more resistant to survive in polluted conditions even.

I think it is too dangerous to consider Culex mosquitoes as well adapted to polluted environments. With 796 species in the world, 173 of them in Brazil, it is difficult to generalize. I think any mosquito species needs to have its preferences known before being utilized as bioindicators.