engleski

Epizoic rotifers on freshwater crustaceans – a short review and new faunistic data

Rotifers are known to live in close association with other organisms, such as algae, macrophytes, invertebrates as well as some vertebrates. Sometimes it is difficult to determine whether these associations are commensal, epiphytic, epizoic or parasitic. Freshwater crustaceans also harbour specific rotifer species and other epizoic organisms. Recent data indicate that more than 50 species of rotifers live on crustaceans. Majority of epizoic rotifers recorded on freshwater crustaceans belong to genera Brachionus, Lepadella and Testudinella. During 2014 and 2015, we examined epizoic community on six different freshwater crayfish species collected from continental and Mediterranean part of Croatia, Europe. Four of them are autochthonous (Astacus astacus, Astacus leptodactylus, Austropotamobius pallipes, Austropotamobius torrentium) and two introduced, invasive species (Pacifastacus leniusculus and Procambarus fallax). The epizoic samples were collected from the surface and from the gill cavity of crayfish. We have found 14 different rotifer taxa, with average density of 9 rotifer individuals per host. The most common rotifer species were Dicranophorus hauerianus and Lepadella parasitica. These species are obligate epizoic organisms and were found exclusively on the autochthonous crayfish species. Density of D. hauerianus significantly and positively correlated with abundance of ciliates, e. g. Epystilis sp., as their main food source. Apart from rotifers, we recorded other epibionts on the studied crayfish hosts: ciliates, nematodes, annelids, tardigrades, copepods, ostracods and chironomides. Sessile ciliates from the genera Epystilis and Vorticella were the most abundant of all epibionts. Also, this research confirmed presence of branchiobdellid annelids on studied crayfish. Our results indicate that rotifer and whole epizoic community composition is complex and can differ significantly between host species.

epibiont; Rotifera; crayfish

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