Have a look at your by-laws to see who is responsible for insect screens. Whilst these almost certainly fall under the definition of being common property, the by-law may make owners responsible for the maintenance of screens which are attached to their lot. Many strata schemes would have adopted the by-law (5) which may be found here:
https://www.austlii.edu.au/au/legis/nsw/consol_act/ssma1996242/sch1.html
My interpretation of that requires the lot owner to repair/replace screens as required. Screens such as those in common stairwells are OC responsibility. There is a similar by-law which makes owners responsible for cleaning their windows, despite glazing in windows being part of common property.
Hope that helps
DaveB