The transfer of pollen from the anthers of one individual to the stigma of another individual of the same species. This is achieved by intermediary agents such as insects (see entomophily
), wind (see anemophily
), or water (see hydrophily
). Birds (see ornithophily) and bats often act as pollinators in the tropics. Cross pollination does not necessarily preclude *self pollination
, although some mechanisms, such as the closing of the stigma lobes after pollination with compatible pollen (as in Mimulus), may reduce the possibility of it occurring.