genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
nematode
The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...
wood
Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulosic fibers that are strong in tension and embedded in a matrix of lignin t ...
pests
PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...
of coconut palms and of pine trees, respectively. Given that ''Bursaphelenchus'' species are usually hard to distinguish from one another except by trained nematologists with access to
microscope
A microscope () is a laboratory equipment, laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic ...
s or
DNA sequence
A nucleic acid sequence is a succession of bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the nu ...
analysis, the entire genus is put under
quarantine
A quarantine is a restriction on the movement of people, animals, and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have bee ...
in some countries. Where this is not the case however, these nematodes are becoming established as
model organism
A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Mo ...
s for nematode
developmental biology
Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of Regeneration (biology), regeneration, asexual reproduction, metamorphosis, and the growth and di ...
,
ecology
Ecology () is the natural science of the relationships among living organisms and their Natural environment, environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosystem, and biosphere lev ...
and
genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinians, Augustinian ...
.
As of 2009, there are about 70 to 90 species in the genus. New taxa are described frequently.
Ecology
''Bursaphelenchus'' contains a single described
hermaphroditic
A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic.
The individuals of many ...
species, ''okinawaensis'', and over 100 described
gonochoristic
In biology, gonochorism is a sexual system where there are two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric.
Gonochorism contras ...
species. They inhabit
soil
Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...
or decaying wood, feeding on the wood itself or
fungal
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as one of the tradit ...
hypha
A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.
Structure
A hypha consists of one o ...
e growing in it, such as those of grey mould (''Botrytis cinerea''). They are sometimes beneficial when they reduce the fungal load inside the wood, but when they consume the plant tissue they are known to cause the death of living trees.
These nematodes are phoretic, dispersed between trees when their
dauer larva
Dauer ( German "", English "the endurance", "persistence"; "unlimited time"
) describes an alternative developmental stage of nematode worms, particularly rhabditids including ''Caenorhabditis elegans'', whereby the larva goes into a type of stas ...
e are transported by
insect
Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...
s. Species involved include
bark beetle
A bark beetle is the common name for the subfamily of beetles Scolytinae. Previously, this was considered a distinct family (Scolytidae), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although th ...
s,
weevil
Weevils are beetles belonging to the superfamily Curculionoidea, known for their elongated snouts. They are usually small – less than in length – and herbivorous. Approximately 97,000 species of weevils are known. They belong to several fa ...
bee
Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamil ...
s. The process of dauer larva formation is not well understood, but it is of research interest because it is significant in the
epidemic
An epidemic (from Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of hosts in a given population within a short period of time. For example, in meningococcal infection ...
s of plant diseases caused by these nematodes, such as pine wilt.
Bursaphelenchus cocophilus
The red ring disease of coconuts and African oil palms is caused by the nematode ''Bursaphelenchus cocophilus''. It is also identified in literature with an alternative scientific name ''Rhadinaphelenchus cocophilus''. The common name, red ring ...
Bursaphelenchus doui
__NOTOC__
''Bursaphelenchus'' is a genus of nematodes (roundworms) in the order Aphelenchida. Most are obligate mycophages, but some feed on wood, with two species, the red ring nematode (''B. cocophilus'') and the pine wood nematode (''B. xylop ...
Bursaphelenchus mucronatus
__NOTOC__
''Bursaphelenchus'' is a genus of nematodes (roundworms) in the order Aphelenchida. Most are obligate mycophages, but some feed on wood, with two species, the red ring nematode (''B. cocophilus'') and the pine wood nematode (''B. xylop ...
Bursaphelenchus xylophilus
''Bursaphelenchus xylophilus'', commonly known as pine wood nematode or pine wilt nematode (PWN), is a species of nematode that infects trees in the ''Pinus'' genus of coniferous trees and causes the disease pine wilt.Bursaphelenchus yongensis''