If the monarch butterfly lives west of the Rocky Mountains, then it will hibernate in and around Pacific Grove, California in eucalyptus trees. Monarch butterflies use the very same trees each and every year when they migrate, which seems odd because they arent the same butterflies that were there last year. These are the new fourth generation of monarch butterflies, so how do they know which trees are the right ones to hibernate in?
Poliovirus can be transmitted through contaminated water and food or through direct contact with someone infected with the virus. Polio is so contagious that anyone living with a recently infected person is likely to become infected, too.oliovirus can be transmitted through contaminated water and food or through direct contact with someone infected with the virus. Polio is so contagious that anyone living with a recently infected person is likely to become infected, too.
Several human diseases caused by protozoa are transmitted by a variety of arthropod vectors (Table). The vectors are not simply 'flying syringes', but represent a second host for the protozoan parasite. Thus the life cycle of vector transmitted diseases also involves complex interactions protozoan-vector interaction analogous to the complex human-protozoan interactions. Vector transmission probably evolved multiple times.