But their lifespan is way shorter and their number is way higher; which means way more feedback from darwinistic evolution.
To me it means their 'intelligent' behavior should be much more a function of being hardcoded in the neuron layout at the genetic level than being in a generic intelligent meat processor at an emergent level.
You can check out a complete fruit fly brain here:
https://fafb-ffn1.storage.googleapis.com/landing.html
Or half of a fruit fly brain that has been more fully reconstructed:
https://www.janelia.org/project-team/flyem/hemibrain