Distribution and Ecology of Myxomycetes in Temperate Forests. II. Patterns of Occurrence on Bark Surface of Living Trees, Leaf Litter, and Dung

Distribution characteristics and diversity of myxomycetes in three parallel rivers in Yunnan, China

Three Parallel Rivers is one of the world's biodiversity hotspots. However, the research on myxomycetes diversity is scarce in this area. Random sampling was used to investigate myxomycetes' diversity and distribution characteristics in this area. One hundred and seventeen species, including three varieties, were obtained, belonging to 28 genera, nine families, and six orders, with Arcyria cinerea and Physarum viride being the dominant species. Moreover, four species and one variety were first reported in China. Twenty-six species and one variety were first reported in Yunnan Province. The species' most commonly utilized substrate for fruiting bodies was decaying wood, and Cribraria was the dominant genus. The species diversity was most abundant in mixed broadleaf-conifer forests. Species similarity between coniferous and broad-leaved forests was much higher than the pairwise comparison of other forest types. NMDS analysis shows that substrate and forest types had insignificant effects on myxomycetes communities, while river valley had a significant effect. The myxomycetes community similarity between river valleys is unrelated to geographical proximity.

Past and Ongoing Field-Based Studies of Myxomycetes

Evidence from molecular studies indicates that myxomycetes (also called myxogastrids or plasmodial slime molds) have a long evolutionary history, and the oldest known fossil is from the mid-Cretaceous. However, they were not "discovered" until 1654, when a brief description and a woodcut depicting what is almost certainly the common species Lycogala epidendrum was published. First thought to be fungi, myxomycetes were not universally recognized as completely distinct until well into the twentieth century. Biodiversity surveys for the group being carried out over several years are relatively recent, with what is apparently the first example being carried out in the 1930s. Beginning in the 1980s, a series of such surveys yielded large bodies of data on the occurrence and distribution of myxomycetes in terrestrial ecosystems. The most notable of these were the All Taxa Biodiversity Inventory (ATBI) project carried out in the Great Smoky Mountains National Park, the Planetary Biodiversity Inventory Project (PBI) carried out in localities throughout the world, and the Myxotropic project being carried out throughout the Neotropics. The datasets available from both past and ongoing surveys now allow global and biogeographical patterns of myxomycetes to be assessed for the first time.

Association between corticolous myxomycetes and tree vitality in Cryptomeria japonica

The bark of live trees provides an important microhabitat for corticolous myxomycetes. However, the association between the presence of myxomycetes and health of host trees has not been studied in detail. In this study, we aimed to investigate the relationship between tree vitality and myxomycetes on the bark of Cryptomeria japonica trees in a montane forest in western Japan. The vitality of trees was categorized into four grades based on the visual assessment of tree shape and leaf density in the upper branches. Myxomycetes on the bark surface were examined using the moist chamber culture method. A decline in tree vitality increased bark pH and decreased electrical conductivity of the bark exudates. Seventeen myxomycete species were recorded in 74 C. japonica trees. The structure of myxomycete communities varied between healthy and unhealthy trees, and species diversity increased as the vitality declined. The relative abundance of Cribraria confusa decreased as the vitality declined, while that of Paradiacheopsis solitaria increased. The results showed that acidophilic myxomycetes grew on healthy C. japonica bark, but changes in bark pH associated with vitality decline led to the weakening of acidity and shifted the community structure; thus, corticolous myxomycete diversity was enhanced as tree vitality decline.

Distribution and diversity of myxomycetes in Tiantangzhai National Forest Park, China

Although myxomycetes are ubiquitous in terrestrial ecosystems, studies on their distribution and diversity in subtropical humid forests are still lacking. Field collections and moist chamber cultures were conducted from May to October within a two-year period in the Tiantangzhai National Forest Park of China. A total of 1,492 records representing 73 species belonging to 26 genera were obtained, of which 243 records/37 species were from field collections, and 1,249 records/52 species were from moist chamber cultures. Among the specimens obtained by culturing, 896 records/38 species and 353 records/37 species were obtained from living bark and ground litter, respectively. ANOVA showed that the sampling months had significant impacts on collection of myxomycetes from field and those that inhabit litter. An LEfSe analysis indicated that Arcyria was significantly abundant in August, while Stemonitis and Physarum were more abundant in July when collected from field. An RDA analysis showed that temperature was the main factor that affected the litter-inhabiting myxomycetes. The ANOVA indicated that forest type was the significant factor for bark-inhabiting myxomycetes. Diderma effusum was primarily obtained from mixed forests, while Clastoderma debaryanum and Colloderma oculatum were more common in coniferous forests. The RDA analysis indicated that the vegetation, pH, water retention, and elevation were the primary factors that affected the bark-inhabiting myxomycetes.

Tyrophagus putrescentiae (Sarcoptiformes: Acaridae) in the in vitro cultures of slime molds (Mycetozoa): accident, contamination, or interaction?

Tyrophagus putrescentiae (Schrank), commonly known as the cereal mite, cheese mite, or ham mite, is a cosmopolitan species reported from various environments in the wild, including soil, plant material and vertebrate nests. It has also been recognized as a common pest of food storages, mycological collections as well as plant and invertebrate laboratory cultures. Laboratory observations indicate that T. putrescentiae feeds on a large range of dermatophytes, yeasts and molds. We have observed the interspecific relation between this mite and several species of true slime molds (Mycetozoa) under laboratory conditions, which confirms the very broad spectrum of feeding habits of T. putrescentiae. Mycetozoans were grown in semi-sterile in vitro cultures and fed with oat flour or oat flakes. Tyrophagus putrescentiae displayed affinity to all macroscopically identifiable stages of the life cycle of Fuligo septica (L.) F.H. Wigg, Physarum polycephalum Schwein and the Didymium sp. complex [Didymium iridis (Ditmar) Fr., Didymium nigripes (Link) Fr. and Didymium bahiense Gottsb.]: live, decaying or dead plasmodia, sporangia, aethalia, spores and sclerotia. The relation carrying symptoms of various types of interspecific interaction, is hypothesized to form an evolutionarily young phenomenon, which not only identifies a new aspect of mycetozoal biology, but also presents the cereal mite as a species of high adaptive potential.

Diversity and Ecology of Myxomycetes from Kütahya and Konya (Turkey) with Four New Records

In this study, we examined myxomycetes that developed in moist chamber cultures of substrata material collected from Kütahya and Konya provinces in Turkey. We collected bark samples from living trees, plant litter from the ground, standing dead wood or stumps, and downed and decayed wood or bark and placed them in the moist chamber cultures. We identified 36 species belonging to 12 genera of myxomycetes. The species determined are listed, and four new records, Didymium balearicum Ing, Macbrideola oblonga Pando & Lado, Paradiacheopsis erythropodia (Ing) Nann-Bremek. and Perichaena pedata (Lister & G. Lister) G. Lister, are added to the mycoflora of Turkey.