Identification of the missing links in parasite–host networks using the dark diversity concept: a case study with two taxonomic groups of ectoparasitic arthropods and small mammalian hosts

Abstract

Abstract Dark diversity (DD) is represented by species that may potentially inhabit a locality but are absent. We applied this approach to identify missing species and links in the interaction networks of fleas and gamasid mites with small mammals and asked (a) which factors affect host, parasite or interaction (= link) DD and (b) whether the probability of an interaction to be missing is associated with the host and/or the parasite traits. The DD of both parasite taxa increased with an increase in host DD. The DD of interactions increased with an increase in the DD of the respective parasite taxon. The quantity of missing flea–host links was affected by environment, whereas that of mite–host links was affected by host DD. The values of the probability of an interaction to belong to DD were similar (= repeatable) within host and flea, but not mite, species. The probability of a flea–host and a mite–host interaction to be missing was higher if social hosts that possessed complex shelter, had low population densities but large geographic ranges. The probability of a flea–host interaction to be missing was higher if a flea species was not abundant and preferred to spend most of its life on either the body or nest of its host but not both. In conclusion, we propose a relatively simple way to apply the dark diversity concept to assess the quantity of missing links in parasite–host networks, to identify these links, and to relate the probability of a link to be missing with parasite and/or host traits.