Originally Posted by VEGANGELICA

ProggyMan, I brush mosquitoes away...gently.

I see your underlying question as a very important one: how do we go about deciding what value another being's life has to us? This question is important for how we treat not just non-human animals but also humans, and people can't even decide on an answer for that! For example, some people feel killing humans in war is acceptable, even innocent bystanders who are "collateral damage."

My decisions about when to kill any animal are affected by my perception of whether it is a threat to me and whether there is a way to get away without either of us being harmed. If a man were standing in front of me, planning to gun me down, and I as a police officer drew my gun, I hope I would try to maim the man rather than shoot to kill. This goes for an attacking human and an attacking tiger and an attacking mosquito.

My full answer about mosquitoes is that if I am outside, I brush them away and run away a little. If one is biting me, the damage/possible infection with West Nile Virus is already done, and I brush the plump, blood-engorged mosquito away. Sometimes, if a mosquito is hovering near me at bedtime indoors, I do try to kill it because I fear that it will bite me in my sleep, though I transport live flies and spiders outside of my home to release them since they are no significant threat to me.