Bat bugs may move into human living areas and incidentally bite people, with such migrations particularly common when bats migrate or are eliminated from the building. However, in the absence of the bat hosts, these insects cannot sustain and reproduce. http://www.ext.colostate.edu/pubs/insect/05574.html
Adaptation
Head lice eat blood from attaching themselves to someone's head. Each only needs a small amount of blood to survive though.
On a purely biological level, to survive (for a while), reproduce then die.
yes human being can't survive without fresh water
We cannot survive without water for three day
A human can only survive 1 week without water, and 2 weeks without food
You can survive without it!
Because HIV needs human immune cells to reproduce and does not survive in an insect.
A human can survive without food for about 1 to 2 months, as long as they are consuming water.
No. It is not necessary for EVERY member of a species to reproduce in order for the species to survive. Consider humans. Some are infertile and can't reproduce, and some choose not to reproduce, yet the human species survives.
Yes because they survive on plant, not human.
No, we can survive without music.