Symbiotic Harpellales (Trichomycetes) in Tasmanian aquatic insects

Surveys for symbiotic fungi in the guts of aquatic insect larvae (Trichomycetes: Harpellales) in Tasmania, Australia, resulted in the discovery of four new species: two in Gripopterygidae (Plecoptera) nymphs, Plecopteromyces leptoperlarum and P. trinotoperlarum, and two associated with Diptera larvae, Smittium magnosporum in Thaumaleidae and Stachylina dolichospora in Chironomidae. Previously described species of Harpellales from other localities are reported and new host records summarized. A key to all Tasmanian species of Harpellales is provided.     

Trichomycetes (Zygomycota) in the digestive tract of arthropods in Amazonas, Brazil

Eight species of Harpellales and three species of Eccrinales (Zygomycota: Trichomycetes) were found associated with the digestive tract of arthropods from terrestrial and aquatic environments in the central Amazon region of Brazil. New species of Harpellales include: Harpella amazonica, Smittium brasiliense, Genistellospora tropicalis in Simuliidae larvae and Stachylina paucispora in Chironomidae larvae. Axenic cultures of S. brasiliense were obtained. Probable new species of Enterobryus (Eccrinales), Harpella, and Stachylina (Harpellales) are described but not named. Also reported are the previously known species of Eccrinales, Passalomyces compressus and Leidyomyces attenuatus in adult Coleoptera (Passalidae), and Smittium culisetae and Smittium aciculare (Harpellales) in Culicidae and Simuliidae larvae, respectively. Comments on the distribution of some of these fungi and their hosts in the Neotropics are provided.     

New species and summary of Iberian Harpellales

The occurrence of three new species of Harpellales in the Iberian Peninsula is reported. Capniomyces celatus was found in Nemouridae (Plecoptera) nymphs, Stipella latispora in Simuliidae (Diptera) larvae and Legeriomyces dolabrae with Baetidae (Ephemeroptera) nymphs. These species are differentiated from others by thalli and/or reproductive structures. Geographic range extensions for other species of Harpellales also are reported; these are Graminella bulbosa, Pennella angustispora, Spartiella barbata, Stachylina euthena, St. grandispora, St. pedifer, St. penetralis, St. prolifica, St. robusta and Stipella vigilans. All are compared with related taxa and are illustrated with photographs. Finally a summary of the known Harpellales occurring in the Iberian territory is provided with data on their distribution and ecology.     

Trichomycete insect symbionts in Great Smoky Mountains National Park and vicinity

Collections of trichomycete symbionts of larval aquatic insects in Great Smoky Mountains National Park and vicinity in the southern Appalachian region of the USA resulted in finding many taxa of Harpellales, including an unusual new monotypic genus, Barbatospora ambicaudata in Simuliidae, and five new species in Thaumaleidae or Chironomidae, Harpellomyces montanus, Smittium lentaquaticum, Sm. minutisporum, Stachylina gravicaudata and St. stenospora. In addition a new species of Amoebidium (Amoebidiales), A. appalachense, attached to the anal tubules of bloodworms (Chironomidae) is described. Axenic cultures of three of the new taxa were obtained, plus Sm. culisetae. Fourteen identified species representing 13 genera of previously known Harpellales are recorded from Plecoptera, Ephemeroptera and Diptera, as well as a new Dipteran host record for an unidentified harpellid that was found in a Blephariceridae. Also identified were Paramoebidium corpulentum and many undetermined species of Paramoebidium (Amoebidiales) from four orders of aquatic insect larvae. The occurrence of an Enterobryus species in Diplopoda and another Eccrinales from an aquatic beetle is noted. Amoebidiales,     

Trichomycete gut fungi from tropical regions of the world

Fifty-nine species of gut fungi in the orders Harpellales and Asellariales, Class Trichomycetes, have been collected in eight tropical regions of the world, some species occurring in more than one geographic region. Regarding the Harpellales, the rather low number of taxa, compared to reports in more temperate localities, is due primarily to relatively few collections in the tropics, as well as the usually warmer waters found in tropical regions that often have a lower species richness of potential immature insect hosts. Asellariales in freshwater, marine, and terrestrial habitats, likewise, have been seldom inventoried in the tropics. Nonetheless, it is clear that the tropics are fertile grounds for discovering new genera and species, and future investigations will undoubtedly reveal many new taxa that will lead to a better understanding of the evolution and biogeography of Trichomycetes.     

Prevalence dynamics of two endosymbiont fungi (Orphella spp. Harpellales: Kickxellomycotina) and host shift among different Leuctra (Plecoptera) species in a stream community

This study was conducted to increase the understanding of the temporal dynamics of the plecopteran-associated endosymbiont species Orphella helicospora and Orphella catalaunica (Harpellales, Zygomycota) in the middle reaches of a stream in Montseny Natural Park (Barcelona, Spain). Previous studies addressing the temporal dynamics of Harpellales have focused on Diptera-related species. Statistical analyses revealed that the temporal dynamics of Plecoptera-associated Harpellales do not respond directly to environmental factors but are more directly dependent on biotic factors, such as the particular preference and fitness of each Orphella species towards a specific Leuctra host, the relative host abundance, and its annual cycle. We report that an in situ host shift linked to Leuctra species replacement occurred during the years 2012–2013, with a resulting decline of O. catalaunica in this environment. The ecological implications of the specificity range and fitness of the host are discussed. We also provide information about the possible causes of this macroinvertebrate shift and the effects on the associated endozoic community.     

Trifoliellum bioblitzii, a new genus of trichomycete from mayfly nymphs in Nova Scotia, Canada

Trichomycetes are an ecological group of fungi and protists that colonize the gut lining of invertebrates in aquatic and moist terrestrial habitats. The diversity of this group appears to be high with many new species discovered each year. A new genus of fungal trichomycete, Trifoliellum (Harpellales), is described here with the type species T. bioblitzii. This genus is characterized by having unique, trefoil-shaped asexual spores (trichospores). Another new species, Legeriosimilis halifaxensis, also is described from the same mayfly host, Eurylophella temporalis, collected from the same site near Halifax, Nova Scotia.     

Dacryodiomyces, a new genus of Harpellales in Chironomidae larvae

A new genus of gut fungus in the Harpellales (Trichomycetes) with the type species Dacryodiomyces oklahomensis, found in Chironomidae larvae, is described from northeastern Oklahoma, USA. The most distinguishing characters are the elongate-ovoid zygospores attached to their zygosporophore at one end (Type IV), together with trichospores bearing a collar and a single appendage.     

Prevalence of Harpellales from Chironomidae larvae in phytotelmata from punta Lara Forest, Argentina

Harpellales (Zygomycota: Trichomycetes) fungi are cosmopolitan obligate inhabitants of the gut of immature insects. A biweekly survey of gut fungi associated with chironomid (Chironomidae: Diptera) larvae living in the impounded water from Eryngium cabrerae (Apiaceae) phytotelmata from Punta Lara forest, Argentina, was done Jan 2003-Dec 2004. Two species of Harpellales were associated with chironomid larvae, Smittium phytotelmatum in the hindgut of Polypedilum sp. and Stachylina lentica in the midgut of both Polypedilum sp. and Metriocnemus eryngiotelmatus. No statistically significant differences were recorded in the prevalence of these Harpellales between seasons. Environmental variables (temperature, rainfall and relative humidity), impounded water volume, pH and chironomid larval density did not have an effect on the prevalence of the Trichomycetes.     

Harpellales (Trichomycetes); mycobionts of insecta

Summary

Species of fungi assigned to the Harpellales, Trichomycetes, occur obligately associated with Insecta. Their possession of monosporous merosporangia (trichospores), zygospores, and crosswalls flared around a plugged central pore augurs for close phyletic affinity with the Kickxellales (Zygomycota). Somatic and reproductive thalli occur attached to the cuticle lining the mid- and hindguts of aquatic dipteran larvae and hindguts of ephemeropteran and plecopteran nymphs. This stage is considered commensalistic. In some species a pathogenic stage of the Harpellales is associated with the ovaries and reduces fecundity. At oviposition fungal spores are deposited by the imago at the sites of new larval populations and provide the primary inoculum.     

Klastostachys, a new genus of Harpellales in Chironomidae larvae

Klastostachys reflexa, a new genus and species combination in the Harpellales, is established herein based on Stachylina reflexa, which was described in 1988. This gut fungus was found attached to the peritrophic matrix of small bloodworms, Cryptochironomus sp. (Chironomidae), in the Rocky Mountains of Colorado, USA. Klastostachys resembles Stachylina, a genus common in Chironomidae, but the unbranched thalli of Klastostachys disarticulate and disperse with the trichospores remaining attached to their generative cells. This manner of dissemination is unusual among Harpellales, being noted also for Carouxella spp., but members of that genus have zygospores attached at one pole to the zygosporophore (Type IV), whereas Klastostachys zygospores are medially attached to the zygosporophore at right angles (Type I).     

New species and first records of trichomycetes from immature aquatic insects in Idaho

Trichomycetes, or gut fungi, are currently recognized as an ecological group of fungi and protists that inhabit the guts of immature insects or other stages and types of arthropods. The geographic distribution of these endosymbionts is worldwide. However trichomycete data from the Pacific Northwest are limited and this is the first account of gut fungi in Idaho. We report on the trichomycetes from a single site, Cottonwood Creek at Military Reserve Park, Boise, Idaho, where periodic surveys for more than a year resulted in the discovery of four newly named, three probably new but unnamed and 15 previously known species. Among the Harpellales three new species, Capniomyces sasquatchoides, Harpella torus and Lancisporomyces lampetriformis, are described, with two possibly new species of Smittium detailed but unnamed at this time pending further collections. A Genistelloides cf. hibernus also is included as a possible new species. One new species of Amoebidiales, Paramoebidium hamatum, is described as well. Hosts in which the gut fungi were recovered include larvae or nymphs of Diptera (Chironomidae and Simuliidae), Ephemeroptera (Baetidae) and Plecoptera (Capniidae and Taeniopterygidae). We hope to demonstrate that future surveys or bioprospecting investigations into the biodiversity of these early-diverging fungi in this region and worldwide remain promising.     

Fungal symbionts (Harpellales) in Norwegian aquatic insect larvae

Collections of aquatic insect larvae in Norway, over a 40 d period in May and Aug 2002, resulted in finding more than 25 species and one new genus of Harpellales (Trichomycetes). Nine new fungal symbionts are described and named: Ephemerellomyces aquilonius (a new monotypic genus), Glotzia stenospora and Legeriosimilis europaeus in mayfly nymphs (Ephemeroptera); Genistelloides amplispora and G. communis in stonefly nymphs (Plecoptera); and Smittium biforme, Sm. precipitiorum, Stachylina acutibasilaris and St. lentica in midge larvae (Diptera: Chironomidae). Two possibly new species of Smittium in Chironomidae larvae are described but not formally named. New hosts and biogeographical distributions are recorded for 14 previously described species, including the rare occurrence of Smittium simulii in mosquito larvae.     

The genus Smittium (Trichomycetes, Harpellales) in the Iberian Peninsula

A study of larval Diptera (Chironomidae, Culicidae and Simuliidae) from Spain has been carried out to fulfill a catalogue of species of the genus Smittium (Harpellales: Legeriomycetaceae) present within these hosts. Among the reported taxa, eight are new species: Smittium brevisporum, S. bulbosporo-phorus, S. gracilis, S. hecatei, S. heterosporum, S. inex-pectans, S. prostratum and S. pseudodimorphum. We also report six previously described species, which are new for the Iberian Peninsula: S. alpinum, S. dipterorum, S. megazygosporum, S. pusillum, S. typhellum and S. fecundum. Three other species (S. simulii, S. culicis and S. culisetae) previously were reported from Spain. In two of them (S. fecundum and S. culicis), we describe for the first time the presence of zygospores. Some of the included species have been artificially cultured as well as ultrastructurally studied using scanning electron microscopy (SEM), with the purpose of observing the surface of both trichospores and the trichospore collar and the morphology of the trichospore appendage.     

AXENIC CULTURE OF TWO NEW SPECIES OF BRANCHED TRICHOMYCETES

Two new endocommensal fungi belonging to the Genistellaceae (Harpellales) were isolated in pure culture from the hindguts of Diptera larvae: Smittium culesitae from the mosquito Culesita impatiens, on a 10% brain-heart infusion, and S. simulii from the black fly Simulium argus, on a potato dextrose-yeast extract medium. Both species appear to have no unusual nutritional or cultural requirements and can grow on synthetic media and a variety of extract media, as can also the other 4 existent isolates of Smittium (Rubetella). Identical isolation methods proved unsuccessful for culturing various other genera of Harpellales and Eccrinales, with the exception of an Enterobryus sp. (from the fiddler crab Uca crenulata) which survived several generations before ceasing to grow. The genus Rubetella Tuzet & Manier is discarded in favor of Smittium Poisson, for reasons discussed.     

The effect of temperature and host species on the development of the trichomycete Smittium culisetae (Zygomycota)

We examined the growth and development of the trichomycete Smittium culisetae (Harpellales: Legeriomycetaceae) in the larval hosts Simulium vittatum Zetterstedt (Diptera: Simuliidae) and Aedes aegypti (L.) (Diptera: Culicidae) at three temperatures, 17, 22 and 30 C. Trichospore maturation of Sm. culicetae external to the host as well as the ability of these trichospores to colonize new hosts also was investigated. Although the development of Sm. culisetae varied with both temperature and host there was a pattern of maximum trichospore production at 48-72 h postinoculation. In addition thalli under laboratory conditions are capable of spore production after extraction from a host and these trichospores can colonize new hosts. Furthermore this was noted to occur in both host species. These results suggest that synchrony between host and symbiont development is not as tightly coupled as previously assumed.