Fig. 5.

Morphological, ontogenetic and behavioural constraints for phoretic strategies among apterous soil-dwelling arthropods. Three criteria shape the phoretic interactions of apterous arthropods with larger hosts, introducing the new case of collembola (Symphypleona). Cases of collembolan (symphypleonan) phoresy correspond with a specific set of conditions that are not met by other phoretic soil-dwellers. Criteria support the heterogeneous nature of reports of these different associations in modern instances, with the so far totally unreported case of modern Symphypleona associations. * much smaller relative to all types of other soil arthropods; ** no specific phoretic lifestage during ontogeny; *** of claws or mouthparts