Larval parasitism of spring-dwelling alpine water mites (Hydrachnidia, Acari): a study with particular reference to chironomid hosts

Abstract

During faunistic investigations on spring habitats in the alpine National Park Berchtesgaden (Bavaria, Germany), water mites were found to be the group with the highest share of species strongly adapted to springs. At four sample sites at two spring complexes, insect emergence was screened for parasitism by larval water mites. A total of at least 36 host species were recorded as being parasitized by 19 water mite species. As in many other habitats, the most important host taxon was shown to be the nematoceran family Chironomidae, both in the number of species and individuals parasitized. Likewise, the number of water mite species attached to chironomids was high. Further host species were found among the Plecoptera, Trichoptera, Coleoptera, Limoniidae and Empididae (Diptera). These taxa were only parasitized by a single water mite species in each case. For 13 mite species, new hosts were recorded for the first time. For another six species, the known host spectrum could be confirmed and/or supplemented. The parasitological data presented (e.g., prevalences, selected attachment sites on the host, larval phenology, intensity of parasitism) provide, in most cases, basic information concerning previously unknown parasite-host associations. At this time, the reason for the strong crenobiosis in water mites cannot be explained by their parasitism.

First record of larvae of the water mite Hydrachna processifera Piersig, 1895 from Turkey (Acari, Hydrachnidia, Hydrachnidae)

“…Of course, the data obtained here should be approached with great caution, as they are based on a very small number of observations. The present study confirms a low prevalence and intensity of infestation of water beetles and water bugs found by other authors (Zawal 2002, 2003b, Biesiadka and Cichocka 1994) compared to dragonflies (Baker et al 2008, Zawal and Szlauer-Łukaszewska 2012, Zawal and Buczyński 2013, Zawal et al 2017) but similar to flies and caddisflies (Fairchild and Lewis 1987, Martin et al 2010, Buczyńska et al 2015, Stryjecki et al 2015). …”

Hidden biodiversity revealed by integrated morphology and genetic species delimitation of spring dwelling water mite species (Acari, Parasitengona: Hydrachnidia)

“…This indicates that species diversity related research questions such as host specificity of different water mite species need to be reconsidered. Hygrobates norvegicus , Partnunia steinmanni and Ljania bipapillata were shown to have a rather wide host species spectrum [18, 19]. Considering our results, which indicate that these three morphologically described taxa consist of several novel species, the number of hosts per water mite species could be lower and reveal a tendency towards high host specificity.…”

“…This would promote reproductive isolation and therefore lead to an increased speciation rate [4, 17], which is among other things an explanation for the relatively high species diversity of water mites in springs. However, the degree of isolation of spring water mite populations is highly dependent on the dispersal abilities of their hosts and influenced by taxon specific host spectra and specificity [5, 18, 19]. Furthermore, the high microhabitat diversity in springs [15, 20], their relatively stable environmental conditions [21, 22] and absence of large predators, e.g.…”

First record of parasitism of water mite larva (Acari: Hydrachnidia) on the pupa of Trichoptera

“…They represent the following families: Aturidae, Feltriidae, Hydrodromidae, Hydryphantidae, Hygrobatidae, Momoniidae, Sperchontidae and Unionicolidae. However, the occurrences of water mites on larval stages have been restricted so far to the families Limnephilidae and Leptoceridae (Smith and Oliver 1986;Fairchild and Lewis 1987;Gerecke 2000;Martin 2009;Martin et al 2010;Więcek et al 2013;Martin and Tempelman 2014). The only information about the presence of larval water mites on caddisfly pupae is provided by Gerecke (2000) without reference to specific details: it refers to an et al 198 undetermined water mite species attached to Drusus sp.…”

“…These hosts, whose imagines are terrestrial (aerial) and preimaginal stages are aquatic, support phoretic mite larvae on aquatic stages first, and then, after the emergence of the host, water mites nd parasitic larvae) on particular development stages of caddisflies, are poorly recognized. Larval water mites were found mainly on imagines, observations on caddisfly larvae were few (Smith and Oliver 1986;Fairchild and Lewis 1987;Martin et al 2010;Więcek et al 2013;Martin and Tempelman 2014) and, on a pupa, exceptional (Gerecke 2000). Nevertheless, larvae of water mites in the phoretic stage definitely occur on caddisfly pupae for this is the only way of getting out of the aquatic environment and entering the parasitic stage on an imaginal caddisfly (Zawal 2003).…”