Ehhhhh, maybe? A fruit fly has 100k neurons. A quick search suggests that these neurons fire somewhere around 10 times per second under stress, so we get about 1 million firings per second, say.

I build audio-oriented neural networks models with ~150 MFLOPS which can run single-threaded on all kinds of phones at about 1000Hz (ie, 1000 inferences per second, each inference using about 150k multiplies). This is single-threaded on an ARM chip.

Piles of caveats: fruit flies also have to maintain breathing, etc. The neurons are more complicated than an artificial neural network activation. But they may contain a lot of vestigial crap, and an activation system which may just be a lot less efficient than silicon.

So, at least for little fruit flies, I don't know that it's THAT far off.