Some fungi are specialized parasites of nematodes, rotifers, and other microscopic animals in the soil (Barron 1977). A common nematode predator is Arthrobotrys oligospora, a fungus that has evolved sticky networks of hyphae for trapping nematodes. We also recognize that organisms traditionally studied as "fungi" belong to three very different unrelated groups: the true fungi in Kingdom Fungi (Eumycota), the Oomycetes, and the slime molds (Fig. Let's briefly consider the major groups in Kingdom Fungi—they will be described in greater detail later. Recent studies have provided support for the recognition of additional phyla, such as Glomeromycota, a group of fungi once placed in Zygomycota that form an association with the roots of most plants (Fig. A group of parasitic organisms called Microsporidia that live inside the cells of animals are also now considered to belong in the fungal kingdom (Fig. This classification is used in the Dictionary of the Fungi (Kirk et al. However, the classification system will undergo additional changes as scientists use new methods to study the fungi. (2011) described the "cryptomycota," a potentially new phylum of organisms within the Kingdom Fungi.
The total number of plant species worldwide is approximately 250,000, and if the ratio of fungi to plants in Great Britain is typical of what occurs elsewhere, there should be at least 1.
5 million species of fungi (6 × 250,000; Hawksworth 2001). 5 million fungal species is a reasonable estimate, the vast majority of all extant fungi are yet to be named.
Insect-attacking fungi, called "entomopathogens," include a wide range of fungi in phyla Ascomycota, Zygomycota and Chytridiomycota. Paradoxically, humans have been using one of these entomopathogens, Ophiocordyceps sinensis, for thousands of years to treat a wide range of ailments.
Some of the best-known and most spectacular entomopathogens belong in the Ascomycota genus Ophiocordyceps and related genera. "Zombie-ant" fungi from Brazil infect insect brains, directing the victim to climb up plants and bite into the plant tissue in a "death grip" (Evans et al. This fungus is an important component of traditional Asian medicine (Fig.
Fungi are involved in a wide range of activities—some fungi are decomposers, parasites or pathogens of other organisms, and others are beneficial partners in symbiosis with animals, plants or algae.
Let's take a brief look at these various ecological groups. Once the nematode is immobilized, the fungus invades and consumes its body. Fortunately, there are relatively few fungal pathogens of vertebrates—only 200-300 species—but some of these fungi can have devastating impacts. This fungus wasn't even known to scientists until 1996, when it was discovered associated with frogs that had died from a mysterious skin disease at the Smithsonian National Zoological Park in Washington, D. The fungus doesn't invade the frog's body, but it is lethal, possibly because it disrupts electrolyte balance leading to cardiac arrest (Voyles et al. Fortunately, this is the only chytrid known to parasitize a vertebrate animal and it appears to infect only amphibians. Another devastating parasite of animals is Geomyces destructans, a cold-loving fungus that causes 'white-nose syndrome' in bats (Blehert et al., 2009). For example, up to 2% of tropical forests are destroyed globally each year (Purvis and Hector 2000).