involving a relationship between two species (= sets of animals or plants in which the members have similar characteristics to each other and can breed with each other) in which one gets an advantage from living closely with the other and the other is not affected by it

Eight species of worm were found in this area living commensally with other animals. 在该地区发现了 8 种与其他动物共生的蠕虫。

This beautiful little crab lives commensally amongst the tentacles of giant anemones.