Mosquitoes

     Why can't mosquitoes live off of something other than blood? Why bite us? And why just certain people and not everyone? What's their problem? It's not on blood type, because people of the same blood type as I don't always get bitten. And it's not on age. My 6 year old brother constantly has mosquito bites. My 9 year old sister never gets bit. I, on the other hand, am attacked as soon as I open the door. It's unfair. No one would mind if they all die. Frogs have other bugs to eat. They have like, flies and such. Why do mosquitoes even have to EXIST. I'm stuck over the fact that I'm constantly having mosquito bites all over while others never get any. What is this? Such shitty fuckery.