Non-volant modes of migration in terrestrial arthropods

Animal migration is often defined in terms appropriate only to the ‘to-and-fro’ movements of large, charismatic (and often vertebrate) species. However, like other important biological processes, the definition should apply over as broad a taxonomic range as possible in order to be intellectually satisfying. Here we illustrate the process of migration in insects and other terrestrial arthropods (e.g. arachnids, myriapods, and non-insect hexapods) but provide a different perspective by excluding the ‘typical’ mode of migration in insects, i.e. flapping flight. Instead, we review non-volant migratory movements, including: aerial migration by wingless species, pedestrian and waterborne migration, and phoresy. This reveals some fascinating and sometimes bizarre morphological and behavioural adaptations to facilitate movement. We also outline some innovative modelling approaches exploring the interactions between atmospheric transport processes and biological factors affecting the ‘dispersal kernels’ of wingless arthropods.