I know when a deer fly lands on my head....it's mor annoying than anything. I've never actually had one bite me where I have hair.

I'm also not certain a mosquito can bite a deer through it's fur, either.

So.......I'm no expert.....but I'd say their fur does a wonderful job of keeping them from getting bitten. In areas around their faces.....where they have little fur.....I'd hope their skin was thick enough to thwart most bites.

I saw a BUNCH of bees get on my Labrador retreiver, once....and ther must have been 50 on her fur. I 'think" I remember the vet saying she actually got stung about 3 times. So I'm sure her fur helped her out in that instance.