A heteroecious

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

is one that requires at least two

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County * Host Island, in the Wilhelm Archipelago, Antarctica People * ...

s. The ''primary host'' is the host in which the parasite spends its adult life; the other is the ''secondary host''. Both hosts are required for the parasite to complete its life cycle. This can be contrasted with an autoecious parasite which can complete its life cycle on a single host species. Many

rust fungi Rusts are fungal plant pathogens of the order Pucciniales (previously known as Uredinales) causing plant fungal diseases. An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus ''Puccinia'', are ...

have heteroecious life cycles: In

parasitology Parasitology is the study of parasites, their host (biology), hosts, and the relationship between them. As a List of biology disciplines, biological discipline, the scope of parasitology is not determined by the organism or environment in questio ...

, heteroxeny, or heteroxenous development, is a synonymous term that characterizes a

whose development involves several

Fungal examples

* ''

Gymnosporangium ''Gymnosporangium'' is a genus of heteroecious plant-pathogenic fungi which alternately infect members of the family Cupressaceae, primarily species in the genus ''Juniperus'' (junipers), and members of the family Rosaceae in the subfamily Amy ...

'' (Cedar-apple rust): the

juniper Junipers are coniferous trees and shrubs in the genus ''Juniperus'' ( ) of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere as far south ...

is the primary ( telial) host and the

apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

pear Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus ''Pyrus'' , in the Family (biology), family Rosaceae, bearing the Pome, po ...

or hawthorn is the secondary (

aecial An aecium (plural aecia) is a specialised reproductive structure found in some plant pathogenic rust fungi that produce aeciospores. Aecia may also be referred to as "cluster cups". The term aecidium (plural aecidia) is used interchangeably but ...

) host. * ''

Cronartium ribicola ''Cronartium ribicola'' is a species of rust (fungus), rust fungus in the family Cronartiaceae that causes the disease white pine blister rust. Other names include: (French), (German), (Spanish). Origin ''Cronartium ribicola'' is native to C ...

'' (White pine blister rust): the primary host are white pines, and currants the secondary. * ''

Hemileia vastatrix ''Hemileia vastatrix'' is a multicellular basidiomycete fungus of the order Pucciniales (previously also known as Uredinales) that causes coffee leaf rust (CLR), a disease affecting the coffee plant. Coffee serves as the obligate host of ...

'' (Coffee rust): the primary host is coffee plant, and the alternate host is unknown. * ''

Puccinia graminis Stem rust, also known as cereal rust, black rust, red rust or red dust, is caused by the fungus ''Puccinia graminis'', which causes significant disease in cereal crops. Crop species that are affected by the disease include bread wheat, durum whe ...

'' (Stem rust): the primary hosts include Kentucky bluegrass, barley, and wheat; barberry is the alternate host. * ''Puccinia coronata'' var. ''avenae'' (Crown rust of oats): Oats are the primary host; '' Rhamnus'' spp. (Buckthorns) are the alternate hosts. * '' Phakopsora meibomiae'' and '' P. pachyrhizi'' (Soybean Rust): the primary host is soybean and various legumes. The alternate host is unknown. * ''

Puccinia porri ''Puccinia porri'' (previously known as ''Puccinia allii'') is a species of rust fungus that causes leek rust. It affects leek, garlic, onion, and chives, and usually appears as bright orange spots on infected plants. Fungus ''Puccinia porri'' ...

'' (Leek rust):

autoecious A heteroecious parasite is one that requires at least two Host (biology), hosts. The ''primary host'' is the host in which the parasite spends its adult life; the other is the ''secondary host''. Both hosts are required for the parasite to compl ...

History

The phenomenon of heteroecy was first discovered by A.S. Ørsted in 1863.Ørsted, A.S. (1863) Om Sygdomme hos Planterne, som foraarsages af Snyltesvampe, navnlig om Rust og Brand og om Midlerne til deres Forebyggelse. Kjøbenhavn

References

Parasitology {{Parasite-stub