Back to basics:
First, intelligence is a concept defined for human beings, using it in another domain would require some reconstruction.
Second, there are only three levels of live organisms: plants, animals, and humans.
Third, humans is the only symbolic species, i.e capable of use symbolic representations (not to be confused with symbolic communication).
On that basis, human intelligence clearly relies on building and processing symbolic representations of (1) their perceptions and designs, and (2) what they know or surmise of others’ representations. The latter appear as a fair account of collective intelligence.