David Hume wrote about this exact thing in (I think) an enquiry concerning human understanding.

Essentially he said all thoughts come from 3 processes:

Cause and effect - think of smoke so think of fire etc.

Continuity in time and/or place - think of kettle so think of toaster etc.

Resemblance - think of a photo so think of the person etc.

The above example would be continuity in place, the carnival lead to thoughts in the same place.

Also cause and effect...why do bees die but wasps not?

Actually possibly resemblance too, as bees and wasps look similar.