Zygomycetes is a class of fungi with over 1,000 known species. This fungal class is extremely diverse, and representatives can be found living all over the world in an assortment of environments and circumstances. Humans often end up interacting with Zygomycetes fungi, usually in the form of bread molds or the feathery molds which appear on spoiled fruit such as strawberries and tomatoes. As a major source of food spoilage, these fungi can have a tremendous economic impact in some regions of the world.
Fungi are placed in this class when they reproduce sexually by making zygospores. Zygospores are very unique fungal spores formed by the fusing of two spores. Other fungi are not capable of this form of sexual reproduction, making Zygomycetes unique. These fungi can also reproduce asexually, usually by producing spores which are spread on the wind or carried by animals. A few species can aim and fire spores in specific directions by developing light-sensitive cells which trigger the release of spores in a particular direction. This controlled dispersal allows the fungus to increase its chance of success.
Some Zygomycetes species are parasitic, living on plants and animals. Others form symbiotic relationships with other organisms, living everywhere from the leaves of plants to the intestines of certain animals. These diverse fungi can also live on dead organic material, such as leaf litter and harvested food. In some organisms, they can cause infections and disease, especially in organisms with compromised immune systems which cannot repel the fungi.
These molds are sometimes known as pin or sugar molds, referencing their distinctive appearance and favorite habitats. Under a microscope, Zygomycetes fungi do indeed look like little pins, with a slightly thready appearance and distinctively large “heads” at the tip of each thread. Many Zygomycetes species also prefer to live on sugar rich substrates like fruits and breads, converting the sugars into energy. This preference for sugars is what causes problems for people, as many foods are rich in sugars which the fungi find immensely useful.
There are some practical uses for these fungi. Several species can be used in the controlled fermentation of foods, and have been utilized for this purpose for centuries. Several Asian foods and drinks in particular are made with the use of fungi from this class. Additional Zygomycetes species can be used in the manufacture of medications such as steroids, and some pharmaceutical labs maintain the fungi in controlled colonies for this purpose.