Asexual reproduction is well suited for organisms that remain in one place and are unable to look for mates, in environments that are stable. It is usually used by simple organisms such as bacteria. However, asexual reproduction does not lead to variation between organisms, meaning that entire groups can be wiped out by disease, or if the stable environment changes. Asexual reproduction can also be found in specimens belonging to a group where mates of the opposite gender are scarse, such as one particular specimen found in the Gensokyo region of Japan, which have adopted asexual production in the absence of males of the species.