A relationship between two different species of organisms in which the larger, or host, organism transports a smaller organism, the guest. It is regarded as a type of commensalism in which the relationship is limited to transportation of the guest. The term is credited to P. Lesne following his observations on the biology of a small fly, Limosina sacra, which is transported by a scarabeid, one of the dung beetles, into its burrow. These burrows are suitable breeding sites for both animals.