Participation of Rossiulus kessleri (Diplopoda, Julida) in the Formation of Algae Assemblages of Urbanized Territories

Abstract

Epi- and endozoochory are well explored phenomena that contribute to the distribution patterns of plant seeds, spores or fruits by vertebrates. It is less known how soil algae may be redistributed due to analogous interactions. We describe the participation of saprophage Rossiulus kessleri (Julidae, Diplopoda) in soil algae redistribution. The research was carried out in a park area of a large industrial megacity in the Dnipro steppe region (Ukrainian North Steppe subzone), Dnipro city. Research material was collected according to zoological and algological methods. The leaf litter of tree species (ash maple Acer negundo, Italian poplar Populus deltoides, locust Robinia pseudoacacia, European white elm Ulmus laevis, Norway maple Acer platanoides) and living diplopods were collected within 1 m2 quadrats along transects. Millipedes were maintained without feeding for five days, after which they were fed with the litter collected previously. Identification of algoflora was conducted in washes from the surface of diplopods’ bodies, its gut washes, in diplopods’ excretions and leaf litter washes. In the leaf litter, as R. kessleri’s feeding base, 14 soil algae species were identified—Nostoc punctiforme, Bracteacoccus minor, Mychonastes homosphaera, Neospongiococcum sp., Chlamydomonas sp., Chlorella vulgaris, Stichococcus bacillaris, Pseudococcomyxa simplex, Desmococcus olivaceus, Trebouxia spp., Klebsormidium flaccidum, Nephrodiella phaseolus, Navicula pelliculosa and Vischeria magna. In body surface washes, five soil algae species were identified, in gut washes seven algae species were found, while in excretions, just four were observed. It was established that not all algae species from the gut washes of R. kessleri were present in excretions. The presence of some representatives of soil algae, for example, Chlorella vulgaris and Vischeria magna, in natural park litter, body surface washes, gut washes and in excretions of R. kessleri, suggests that the given species pass through the diplopod’s gut and stay undamaged. This indicates that soil saprophage R. kessleri contributes to the dispersal of some soil algae representatives through epi- and endozoochory. Our results represent novel contributions to the knowledge of zoochory. It was shown that animals can be involved in dispersal of not only plant parts but also entire organisms, although it is unknown at what scale diplopods contribute to the diversity and dispersal of algae.