| Ascosphaera aggregata | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Eurotiomycetes |
| Order: | Onygenales |
| Family: | Ascosphaeraceae |
| Genus: | Ascosphaera |
| Species: | A. aggregata |
| Binomial name | |
| Ascosphaera aggregata Skou, JP (1975) [1] | |
Ascosphaera aggregata is a species of fungus.
Ascosphaera aggregata, discovered in 1975 by Jens-Peder Skou [1] is a fungus that is related to Ascosphaera apis . [2]
Ascosphaera aggregata is an obligate parasite [3] that causes chalkbrood in bees, [4] symptom manifestations differ depending on age of the larva. [5] It primarily infects alfalfa leafcutting bees, Megachile rotundata . [2] [6] [7] [3] [8] Megachile rotundata infected with A. aggregata have been detected in the United States, Canada, [9] and South America. [5] Other bee species that A. aggregata has been seen to infect include the red mason bee ( Osmia rufa [8] ), the patchwork leafcutter bee ( Megachile centuncularis [8] ), Megachile pugnata and Megachile relativa . [2] [10] [8]
Ascosphaera aggregata is an obligate parasite that can cause chalkbrood by the fifth instar. [5] The majority of the life cycle and growth of A. aggregata occurs in M. rotundata larvae. Infection of bee larvae occurs only via ingestion of resting spores, [3] and is not possible via spore inhalation nor contact with the fungal vegetative form. [6] [5] Spores develop in the larva and cause it to swell, bursting the larval integument (giving the dead larvae a ragged appearance) [1] and furthering the spread of the fungus. Buildup of larval cadavers traps the unaffected emerging bees, forcing them to chew through the cadavers and be covered in spores. [7] Bees covered in spores then contaminate food provisions for other broods [7] and spread the infection.
Early vegetative growth utilizes gut lumen nutrients. [6] A. aggregata grows through the midgut wall to the hemocoele (event trigger is unknown, not because of lack of space nor food) [6] eventually replacing larval tissue. [3] Resulting larvae are filled with a mycelial mat comprising two layers: a dense inner layer and a less dense outer layer. [6]
Ascospore morphology consists of two layers: an inner chitinous and smooth layer, and an outer layer that is rough, spotted, [1] and not composed of chitin nor cellulose.; [6] ) Ascospore development in A. aggregata is very unique and the resulting structure is referred to as a "spore cyst", or "ascocyst" or "synascus". [8] Sexual development occurs on the outer mycelial mat in the subcuticular region, [3] [6] and is documented to proceed as follows:
Ascosphaera aggregata has been found to be unable to break down chitin. [6] [3]
Although ascospore development is very unique, it is very hard to identify A. aggregata because the spore balls and conidia tend to resemble other species. [12] Recent investigations by James and Skinner (2005) [12] have discovered that PCR of the ITS domain of ribosomal DNA with species specific primer sets allows the detection of fungal DNA (working, even, in asymptomatic individuals). [12] The PCR technique can also be used on hair and honey samples to avoid the difficulty of culturing spores, [12] as spore were shown before to only germinate well in lipids. [13] Storage of the fungus has also proven to be difficult as it collapses after 1–2 months during normal culture passaging. [14] However, Jensen et al. (2009) found that spores could be preserved via cryopreservation or freeze-drying whereas hyphae unfortunately could not be preserved. [14]
Megachile rotundata is the primary pollinator of the commercially grown alfalfa seed, [11] [7] accounting for 46,000 metric tonnes of North American alfafa seed (two-thirds the global production) in 2004. [7] M. rotundata is also the second most valuable field crop pollinator, behind the honey bee, because of the value of alfalfa in animal feed and hay. [7] A. aggregata has been killing this economic pollinator in the US since 1972 [10] and has been reported to be able to kill greater than 50% of a population. [8]
Effective management of the fungus has yet to be discovered, as the current registered treatment in Canada (paraformaldehyde fumigation of spores [7] ) involves a carcinogen and other treatment options (heat and chloride treatments) are expensive and labour-intensive. [7]
Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defining feature of this fungal group is the "ascus", a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of Ascomycota are asexual and thus do not form asci or ascospores. Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens such as Cladonia belong to the Ascomycota.
Alfalfa, also called lucerne, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as well as a green manure and cover crop. The name alfalfa is used in North America. The name lucerne is more commonly used in the United Kingdom, South Africa, Australia, and New Zealand. The plant superficially resembles clover, especially while young, when trifoliate leaves comprising round leaflets predominate. Later in maturity, leaflets are elongated. It has clusters of small purple flowers followed by fruits spiralled in two to three turns containing 10–20 seeds. Alfalfa is native to warmer temperate climates. It has been cultivated as livestock fodder since at least the era of the ancient Greeks and Romans.
Megachile rotundata, the alfalfa leafcutting bee, is a European bee that has been introduced to various regions around the world. As a solitary bee species, it does not build colonies or store honey, but is a very efficient pollinator of alfalfa, carrots, other vegetables, and some fruits. Because of this, farmers often use M. rotundata as a pollination aid by distributing M. rotundata prepupae around their crops. Each female constructs and provisions her own nest, which is built in old trees or log tunnels. Being a leafcutter bee, these nests are lined with cut leaves. These bees feed on pollen and nectar and display sexual dimorphism. This species has been known to bite and sting, but it poses no overall danger unless it is threatened or harmed, and its sting has been described as half as painful as a honey bee's.
Megachilidae is a cosmopolitan family of mostly solitary bees. Characteristic traits of this family are the restriction of their pollen-carrying structure to the ventral surface of the abdomen, and their typically elongated labrum. Megachilid genera are most commonly known as mason bees and leafcutter bees, reflecting the materials from which they build their nest cells ; a few collect plant or animal hairs and fibers, and are called carder bees, while others use plant resins in nest construction and are correspondingly called resin bees. All species feed on nectar and pollen, but a few are kleptoparasites, feeding on pollen collected by other megachilid bees. Parasitic species do not possess scopae. The motion of Megachilidae in the reproductive structures of flowers is energetic and swimming-like; this agitation releases large amounts of pollen.
Atta is a genus of New World ants of the subfamily Myrmicinae. It contains at least 17 known species.
Ophiocordyceps sinensis, known colloquially as caterpillar fungus, is an entomopathogenic fungus in the family Ophiocordycipitaceae. It is mainly found in the meadows above 3,500 metres (11,500 ft) on the Tibetan Plateau in Tibet and the Himalayan regions of Bhutan, India, and Nepal. It parasitizes larvae of ghost moths and produces a fruiting body which is valued in traditional Chinese medicine as an aphrodisiac. Caterpillar fungus contains the compound cordycepin, an adenosine derivative. However, the fruiting bodies harvested in nature usually contain high amounts of arsenic and other heavy metals, so they are potentially toxic and sales have been strictly regulated by China's State Administration for Market Regulation since 2016.
The Sapygidae are a family of solitary kleptoparasitic aculeate wasps. They are generally black wasps, similar in appearance to some Tiphiidae or Thynnidae, with white or yellow markings developed to various degrees.
Bee pollen, also known as bee bread and ambrosia, is a ball or pellet of field-gathered flower pollen packed by worker honeybees, and used as the primary food source for the hive. It consists of simple sugars, protein, minerals and vitamins, fatty acids, and a small percentage of other components. Bee pollen is stored in brood cells, mixed with saliva, and sealed with a drop of honey. Bee pollen is harvested as food for humans and marketed as having various, but yet unproven, health benefits.
The genus Megachile is a cosmopolitan group of solitary bees, often called leafcutter bees or leafcutting bees; it also includes the called resin bees and mortar bees. While other genera within the family Megachilidae may chew leaves or petals into fragments to build their nests, certain species within Megachile neatly cut pieces of leaves or petals, hence their common name. This is one of the largest genera of bees, with more than 1500 species in over 50 subgenera. The alfalfa leafcutter bee is managed on a commercial scale for crop pollination, and has been introduced by humans to various regions around the world.
Didymella bryoniae, syn. Mycosphaerella melonis, is an ascomycete fungal plant pathogen that causes gummy stem blight on the family Cucurbitaceae, which includes cantaloupe, cucumber, muskmelon and watermelon plants. The anamorph/asexual stage for this fungus is called Phoma cucurbitacearum. When this pathogen infects the fruit of cucurbits it is called black rot.
Ascosphaera is a genus of fungi in the family Ascosphaeraceae. It was described in 1955 by mycologists Charles F. Spiltoir and Lindsay S. Olive. Members of the genus are insect pathogens. The type species, A. apis, causes chalkbrood disease in honey bees. The reproductive ascospores of the fungus are produced within a unique structure, the spore cyst, or sporocyst.
The California carpenter bee or Western carpenter bee, Xylocopa californica, is a species of carpenter bee in the order Hymenoptera, and it is native to western North America.
The alkali bee, Nomia melanderi, is a ground-nesting bee native to deserts and semi-arid desert basins of the western United States. It was described by Theodore Dru Alison Cockerell in 1906. While solitary, these bees nest near each other and can form extremely dense aggregations in areas with favorable conditions.
Taphrina caerulescens is a species of fungus in the family Taphrinaceae. It is a pathogenic Ascomycete fungus that causes oak leaf blister disease on various species of oak trees. The associated anamorph species is Lalaria coccinea, described in 1990. This disease causes lesions and blisters on Oak leaves. Effects of the disease are mostly cosmetic. Although not taxonomically defined, strains of T. caerulescens have been shown to be host specific with varying ¬ascus morphology between strains. There are differences in strains' abilities to metabolize various carbon and nitrogen compounds. This has been proposed as a method of taxonomically defining subspecies within T. caerulescens.
Ascosphaera callicarpa is a fungus common on the larval feces of the solitary bee Chelostoma florisomne, which nests in the Phragmites reeds of thatched roofs in Europe.
Megachile campanulae, known as the bellflower resin bee, is a species of bee in the family Megachilidae. Described in 1903, these solitary bees are native to eastern North America. Studies in 2013 placed them among the first insect species to use synthetic materials for making nests. They are considered mason bees, which is a common descriptor of bees in several families, including Megachilidae. Within the genus Megachile, frequently also referred to as leafcutter bees, M. campanulae is a member of the subgenus Chelostomoides, which do not construct nests from cut leaves, but rather from plant resins and other materials. Females lay eggs in nests constructed with individual cell compartments for each egg. Once hatched, the eggs progress through larval stages and subsequently will overwinter as pupae. The bees are susceptible to parasitism from several other bee species, which act as brood parasites. They are medium-sized bees and the female adults are typically larger than the males. They are important pollinators of numerous native plant species throughout their range.
Megachile angelarum is a species of bee in the Megachilidae family.
Megachile abacula is a species of bee in the Megachilidae family.
Megachile zombae is a species of bee in the Megachilidae family. Natively endemic to Malawi and identified in 1977, these are solitary bees. The name derives from Greek mega 'large' + cheil- (χειλ) 'lip' and a district Zomba, in Malawi.
