120-601: The durian ( / ˈ d ʊər i ə n / , / ˈ dj ʊər i ə n / ) is the edible fruit of several tree species belonging to the genus Durio . There are 30 recognized species, at least nine of which produce edible fruit. Durio zibethinus , native to Borneo and Sumatra , is the only species available on the international market. It has over 300 named varieties in Thailand and 100 in Malaysia as of 1987. Other species are sold in their local regions. Known in some regions as
240-423: A mutation–selection balance . It is predicted that a viral quasispecies at a low but evolutionarily neutral and highly connected (that is, flat) region in the fitness landscape will outcompete a quasispecies located at a higher but narrower fitness peak in which the surrounding mutants are unfit, "the quasispecies effect" or the "survival of the flattest". There is no suggestion that a viral quasispecies resembles
360-413: A poultice . Southeast Asian traditional beliefs, as well as traditional Chinese food therapy , consider the durian fruit to have warming properties liable to cause excessive sweating . The traditional method to counteract this is to pour water into the empty shell of the fruit after the pulp has been consumed and drink it. An alternative method is to eat the durian in accompaniment with mangosteen, which
480-444: A status symbol indicating wealth. Durian from Thailand retails at around ¥150 (US$ 20), while the more prestigious Musang King variety retails at around ¥500 and can be a birthday or wedding gift. The potential value for exporters has allowed China to leverage Durian as part of trade talks. The entire export of durians from Southeast Asia to China increased from US$ 550 million in 2017, to US$ 6.7 billion in 2023. China's largest imports of
600-400: A "classical" method of determining species, such as with Linnaeus, early in evolutionary theory. However, different phenotypes are not necessarily different species (e.g. a four-winged Drosophila born to a two-winged mother is not a different species). Species named in this manner are called morphospecies . In the 1970s, Robert R. Sokal , Theodore J. Crovello and Peter Sneath proposed
720-424: A 'smallest clade' idea" (a phylogenetic species concept). Mishler and Wilkins and others concur with this approach, even though this would raise difficulties in biological nomenclature. Wilkins cited the ichthyologist Charles Tate Regan 's early 20th century remark that "a species is whatever a suitably qualified biologist chooses to call a species". Wilkins noted that the philosopher Philip Kitcher called this
840-541: A 38–59 cm (15–23 in) long tail. The hind foot measures 9–14.5 cm (3.5–5.7 in). Its weight ranges from 3.4–9.2 kg (7.5–20.3 lb). Some sources claim the species can weigh up to 11 kg (24 lb) (though possibly attained in captivity). The large Indian civet ranges from Nepal , northeast India , Bhutan , Bangladesh to Myanmar , Thailand , the Malay Peninsula and Singapore to Cambodia , Laos , Vietnam and China . In Nepal,
960-428: A connected series of neighbouring populations, each of which can sexually interbreed with adjacent related populations, but for which there exist at least two "end" populations in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population. Such non-breeding, though genetically connected, "end" populations may co-exist in the same region thus closing
1080-598: A cultivar without the characteristic odour. Another hybrid, Chantaburi No. 3, develops the odour about three days after the fruit is picked, which enables an odourless transport yet satisfies consumers who prefer the pungent odour. On 22 May 2012, two other cultivars from Thailand that also lack the usual odour, Long Laplae and Lin Laplae, were presented to the public by Yothin Samutkhiri, governor of Uttaradit province from where these cultivars were developed locally, while he announced
1200-511: A deep caramel flavour with a turpentine odour while red-fleshed durian ( D. graveolens ) emits a fragrance of roasted almonds . The fruit's strong smell has led to its ban from public transport systems in Singapore and in Bangkok. A draft genome analysis of durian indicates it has about 46,000 coding and non-coding genes , among which a class called methionine gamma-lyases – which regulate
1320-457: A dessert called durian (or thurian) guan. In Thailand, durian is eaten fresh with sweet sticky rice, and blocks of durian paste are sold in the markets, though much of the paste is adulterated with pumpkin . Unripe durians are cooked as a vegetable, except in the Philippines, where all uses are sweet rather than savoury. Malaysians make both sugared and salted preserves from durian. When durian
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#17328560186881440-432: A different species from its ancestors. Viruses have enormous populations, are doubtfully living since they consist of little more than a string of DNA or RNA in a protein coat, and mutate rapidly. All of these factors make conventional species concepts largely inapplicable. A viral quasispecies is a group of genotypes related by similar mutations, competing within a highly mutagenic environment, and hence governed by
1560-575: A durian seed, which he planted and cared for on his tropical island off the north coast of Queensland . In 1949, the British botanist E. J. H. Corner published The Durian Theory, or the Origin of the Modern Tree . This proposed that endozoochory (the enticement of animals to transport seeds in their stomach) arose before any other method of seed dispersal , and that primitive ancestors of Durio species were
1680-459: A fruit much loved by a variety of animals, the durian is sometimes taken to signify the animalistic aspect of humans, as in the legend of Orang Mawas , the Malaysian version of Bigfoot, and Orang Pendek , its Sumatran version, both of which have been claimed to feast on durians. In Malaysia, a decoction of the leaves and roots used to be prescribed as an antipyretic . The leaf juice is applied on
1800-508: A genetic boundary suitable for defining a species concept is present. DNA barcoding has been proposed as a way to distinguish species suitable even for non-specialists to use. One of the barcodes is a region of mitochondrial DNA within the gene for cytochrome c oxidase . A database, Barcode of Life Data System , contains DNA barcode sequences from over 190,000 species. However, scientists such as Rob DeSalle have expressed concern that classical taxonomy and DNA barcoding, which they consider
1920-465: A lineage should be divided into multiple chronospecies , or when populations have diverged to have enough distinct character states to be described as cladistic species. Species and higher taxa were seen from the time of Aristotle until the 18th century as categories that could be arranged in a hierarchy, the great chain of being . In the 19th century, biologists grasped that species could evolve given sufficient time. Charles Darwin 's 1859 book On
2040-492: A misnomer, need to be reconciled, as they delimit species differently. Genetic introgression mediated by endosymbionts and other vectors can further make barcodes ineffective in the identification of species. A phylogenetic or cladistic species is "the smallest aggregation of populations (sexual) or lineages (asexual) diagnosable by a unique combination of character states in comparable individuals (semaphoronts)". The empirical basis – observed character states – provides
2160-449: A particular species, including which genus (and higher taxa) it is placed in, is a hypothesis about the evolutionary relationships and distinguishability of that group of organisms. As further information comes to hand, the hypothesis may be corroborated or refuted. Sometimes, especially in the past when communication was more difficult, taxonomists working in isolation have given two distinct names to individual organisms later identified as
2280-400: A perfect model of life, it is still a useful tool to scientists and conservationists for studying life on Earth, regardless of the theoretical difficulties. If species were fixed and clearly distinct from one another, there would be no problem, but evolutionary processes cause species to change. This obliges taxonomists to decide, for example, when enough change has occurred to declare that
2400-521: A range of 8–20% among different durian varieties. Durian flesh contains diverse polyphenols , especially myricetin , and various carotenoids , including a rich content of beta-carotene . In 2019, ethanethiol and its derivatives was identified as a source of the fetid smell. However, the biochemical pathway by which the plant produces ethanethiol remained unclear. People in Southeast Asia with frequent exposures to durian are able to easily distinguish
2520-400: A short way of saying that something applies to many species within a genus, but not to all. If scientists mean that something applies to all species within a genus, they use the genus name without the specific name or epithet. The names of genera and species are usually printed in italics . However, abbreviations such as "sp." should not be italicised. When a species' identity is not clear,
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#17328560186882640-404: A specialist may use "cf." before the epithet to indicate that confirmation is required. The abbreviations "nr." (near) or "aff." (affine) may be used when the identity is unclear but when the species appears to be similar to the species mentioned after. With the rise of online databases, codes have been devised to provide identifiers for species that are already defined, including: The naming of
2760-523: A species as groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups. It has been argued that this definition is a natural consequence of the effect of sexual reproduction on the dynamics of natural selection. Mayr's use of the adjective "potentially" has been a point of debate; some interpretations exclude unusual or artificial matings that occur only in captivity, or that involve animals capable of mating but that do not normally do so in
2880-400: A species as determined by a taxonomist. A typological species is a group of organisms in which individuals conform to certain fixed properties (a type), so that even pre-literate people often recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens (such as longer or shorter tails) would differentiate the species. This method was used as
3000-488: A species. All species definitions assume that an organism acquires its genes from one or two parents very like the "daughter" organism, but that is not what happens in HGT. There is strong evidence of HGT between very dissimilar groups of prokaryotes , and at least occasionally between dissimilar groups of eukaryotes , including some crustaceans and echinoderms . The evolutionary biologist James Mallet concludes that there
3120-685: A species. Generally the term includes the unknown element of a distinct act of creation. Many authors have argued that a simple textbook definition, following Mayr's concept, works well for most multi-celled organisms , but breaks down in several situations: Species identification is made difficult by discordance between molecular and morphological investigations; these can be categorised as two types: (i) one morphology, multiple lineages (e.g. morphological convergence , cryptic species ) and (ii) one lineage, multiple morphologies (e.g. phenotypic plasticity , multiple life-cycle stages). In addition, horizontal gene transfer (HGT) makes it difficult to define
3240-519: A taxonomic decision at the discretion of cognizant specialists, is not governed by the Codes of Zoological or Botanical Nomenclature, in contrast to the PhyloCode , and contrary to what is done in several other fields, in which the definitions of technical terms, like geochronological units and geopolitical entities, are explicitly delimited. The nomenclatural codes that guide the naming of species, including
3360-506: A traditional biological species. The International Committee on Taxonomy of Viruses has since 1962 developed a universal taxonomic scheme for viruses; this has stabilised viral taxonomy. Most modern textbooks make use of Ernst Mayr 's 1942 definition, known as the Biological Species Concept as a basis for further discussion on the definition of species. It is also called a reproductive or isolation concept. This defines
3480-447: A variation on the morphological species concept, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms. It differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species
3600-515: A variety of reasons. Viruses are a special case, driven by a balance of mutation and selection , and can be treated as quasispecies . Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics . Early taxonomists such as Linnaeus had no option but to describe what they saw: this was later formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts,
3720-576: Is glutinous rice steamed with coconut milk and served with ripened durian. In Sabah , red durian is fried with onions and chilli and served as a side dish. Red-fleshed durian is traditionally added to sayur , an Indonesian soup made from freshwater fish. Ikan brengkes tempoyak is fish cooked in a durian-based sauce, traditional in Sumatra . Raw durian is composed of 65% water, 27% carbohydrates (including 4% dietary fibre ), 5% fat and 1% protein . In 100 grams, raw or fresh frozen durian provides 33% of
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3840-547: Is solitary and nocturnal . It spends most of the time on the ground. It is an opportunistic hunter that preys on a wide variety of small animals. Radio-tracked large Indian civets in Thailand had home ranges of 2.7 to 8.8 km (1.0 to 3.4 sq mi). Viverra zibetha is a protected species in Hong Kong under the Wild Animals Protection Ordinance Cap 170, though it has not been recorded in
3960-438: Is "an entity composed of organisms which maintains its identity from other such entities through time and over space, and which has its own independent evolutionary fate and historical tendencies". This differs from the biological species concept in embodying persistence over time. Wiley and Mayden stated that they see the evolutionary species concept as "identical" to Willi Hennig 's species-as-lineages concept, and asserted that
4080-487: Is "like eating sweet raspberry blancmange in the lavatory". The travel and food writer Richard Sterling states that "its odor is best described as pig-excrement, turpentine and onions, garnished with a gym sock." Other comparisons have been made with the civet , sewage , stale vomit , skunk spray and used surgical swabs . Such descriptions may reflect the odour's variability. Different species and cultivars vary markedly in aroma; for example, red durian ( D. dulcis ) has
4200-571: Is a viverrid native to South and Southeast Asia . It is listed as Least Concern on the IUCN Red List . The global population is thought to be decreasing due to hunting and trapping driven by the demand for bushmeat . The large Indian civet is grey or tawny and has a black spinal stripe running from behind the shoulders to the root of the tail. The front of the muzzle has a whitish patch emphasized by blackish behind on each side. The chin and fore throat are blackish. The sides and lower surface of
4320-400: Is a group of sexually reproducing organisms that recognise one another as potential mates. Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms; no matter whether populations can hybridise successfully, they are still distinct cohesion species if
4440-458: Is a set of organisms adapted to a particular set of resources, called a niche, in the environment. According to this concept, populations form the discrete phenetic clusters that we recognise as species because the ecological and evolutionary processes controlling how resources are divided up tend to produce those clusters. A genetic species as defined by Robert Baker and Robert Bradley is a set of genetically isolated interbreeding populations. This
4560-414: Is called speciation . Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book The Origin of Species . Speciation depends on a measure of reproductive isolation , a reduced gene flow. This occurs most easily in allopatric speciation, where populations are separated geographically and can diverge gradually as mutations accumulate. Reproductive isolation
4680-412: Is called the specific name or the specific epithet (in botanical nomenclature , also sometimes in zoological nomenclature ). For example, Boa constrictor is one of the species of the genus Boa , with constrictor being the species' epithet. While the definitions given above may seem adequate at first glance, when looked at more closely they represent problematic species concepts. For example,
4800-506: Is considered to have cooling properties. Pregnant women or people with high blood pressure are traditionally advised not to consume durian. The Javanese believe durian to have aphrodisiac qualities, and impose a set of rules on what may or may not be consumed with it or shortly thereafter. A saying in Indonesian , durian jatuh sarung naik , meaning "the durian falls and the sarong comes up", refers to this belief. The warnings against
4920-403: Is described formally, in a publication that assigns it a unique scientific name. The description typically provides means for identifying the new species, which may not be based solely on morphology (see cryptic species ), differentiating it from other previously described and related or confusable species and provides a validly published name (in botany) or an available name (in zoology) when
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5040-671: Is further weakened by the existence of microspecies , groups of organisms, including many plants, with very little genetic variability, usually forming species aggregates . For example, the dandelion Taraxacum officinale and the blackberry Rubus fruticosus are aggregates with many microspecies—perhaps 400 in the case of the blackberry and over 200 in the dandelion, complicated by hybridisation , apomixis and polyploidy , making gene flow between populations difficult to determine, and their taxonomy debatable. Species complexes occur in insects such as Heliconius butterflies, vertebrates such as Hypsiboas treefrogs, and fungi such as
5160-726: Is hard or even impossible to test. Later biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, and the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: (1) agamospecies for asexual organisms (2) biospecies for reproductively isolated sexual organisms (3) ecospecies based on ecological niches (4) evolutionary species based on lineage (5) genetic species based on gene pool (6) morphospecies based on form or phenotype and (7) taxonomic species,
5280-591: Is medium-thick, solid, yellow in colour, and sweet; and "Red Prawn" ( Udang Merah , D175), found in the states of Pahang and Johor . The fruit is medium-sized, oval, brownish green, with short thorns. The flesh is thick, not solid, yellow-coloured, and has a sweet taste. Indonesia has more than 100 varieties of durian. The most cultivated species is D. zibethinus . Notable varieties are Sukun ( Central Java ), sitokong ( Betawi ), sijapang (Betawi), Simas ( Bogor ), Sunan ( Jepara ), si dodol and si hijau ( South Kalimantan ), and Petruk (Central Java). In Thailand, Mon Thong
5400-421: Is minced with salt, onions and vinegar, it is called boder . In Kelantan of Malaysia, fresh durian or tempoyak is mixed with onion and chilli slices, lime juice and budu (fermented anchovy sauce) and eaten as a condiment with rice-based meals. The seeds, which are the size of chestnuts, can be eaten boiled, roasted or fried in coconut oil , with a texture that is similar to taro or yam , but stickier. In Java ,
5520-403: Is no easy way to tell whether related geographic or temporal forms belong to the same or different species. Species gaps can be verified only locally and at a point of time. One is forced to admit that Darwin's insight is correct: any local reality or integrity of species is greatly reduced over large geographic ranges and time periods. The botanist Brent Mishler argued that the species concept
5640-468: Is not valid, notably because gene flux decreases gradually rather than in discrete steps, which hampers objective delimitation of species. Indeed, complex and unstable patterns of gene flux have been observed in cichlid teleosts of the East African Great Lakes . Wilkins argued that "if we were being true to evolution and the consequent phylogenetic approach to taxa, we should replace it with
5760-459: Is ready to eat when its husk begins to crack. However, the ideal stage of ripeness to be enjoyed varies from region to region in Southeast Asia and by species. Some species grow so tall that they can only be collected once they have fallen to the ground, whereas most cultivars of D. zibethinus are nearly always cut from the tree and allowed to ripen while waiting to be sold. Some people in southern Thailand prefer their durians relatively young, when
5880-586: Is similar to Mayr's Biological Species Concept, but stresses genetic rather than reproductive isolation. In the 21st century, a genetic species could be established by comparing DNA sequences. Earlier, other methods were available, such as comparing karyotypes (sets of chromosomes ) and allozymes ( enzyme variants). An evolutionarily significant unit (ESU) or "wildlife species" is a population of organisms considered distinct for purposes of conservation. In palaeontology , with only comparative anatomy (morphology) and histology from fossils as evidence,
6000-425: Is sometimes an important source of genetic variation. Viruses can transfer genes between species. Bacteria can exchange plasmids with bacteria of other species, including some apparently distantly related ones in different phylogenetic domains , making analysis of their relationships difficult, and weakening the concept of a bacterial species. Viverra zibetha The large Indian civet ( Viverra zibetha )
6120-455: Is that the durian is harmful when eaten with coffee or alcoholic beverages. The latter belief can be traced back at least to the 18th century when Rumphius stated that one should not drink alcohol after eating durians as it will cause indigestion and bad breath . In 1929, J. D. Gimlette wrote in his Malay Poisons and Charm Cures that the durian fruit must not be eaten with brandy . In 1981, J. R. Croft wrote in his Bombacaceae: In Handbooks of
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#17328560186886240-600: Is the most commercially sought after cultivar, for its thick, full-bodied creamy and mild sweet-tasting flesh with moderate smell and smaller seeds, while Chanee is most resistant to infection by Phytophthora palmivora . Kan Yao is less common, but prized for its longer window of time when it is both sweet and odourless. Among the cultivars in Thailand, five are currently in large-scale commercial cultivation: Chanee, Mon Thong, Kan Yao, Ruang, and Kradum. By 2007, Thai government scientist Songpol Somsri had crossbred more than ninety varieties of durian to create Chantaburi No. 1,
6360-594: Is threatened by hybridisation, but this can be selected against once a pair of populations have incompatible alleles of the same gene, as described in the Bateson–Dobzhansky–Muller model . A different mechanism, phyletic speciation, involves one lineage gradually changing over time into a new and distinct form (a chronospecies ), without increasing the number of resultant species. Horizontal gene transfer between organisms of different species, either through hybridisation , antigenic shift , or reassortment ,
6480-554: Is unsurpassed." Wallace described himself as being at first reluctant to try it because of the aroma, but on eating one in Borneo "out of doors, I at once became a confirmed Durian eater". He cites another writer as stating: "To those not used to it, it seems at first to smell like rotten onions, but immediately after they have tasted it they prefer it to all other food. The natives give it honourable titles, exalt it, and make verses on it." The novelist Anthony Burgess wrote that eating durian
6600-743: The Oxford English Dictionary , the alternate spelling durion was first used in a 1588 translation of The History of the Great and Mighty Kingdom of China and the Situation Thereof by the Spanish explorer Juan González de Mendoza . Other historical variant spellings include duryoen , duroyen , durean , and dorian . The name of the type species , D. zibethinus , is derived from Italian zibetto , (the civet ). Durian trees are large, growing to 25–50 metres (80–165 feet) in height depending on
6720-576: The Daily Value (DV) of thiamine and a moderate content of other B vitamins , vitamin C , and the dietary mineral manganese (15–24% DV, table). Different durian varieties from Malaysia, Thailand and Indonesia vary in their carbohydrate content from 16 to 29%, fat content from 2–5%, protein content from 2–4%, and dietary fibre content from 1–4%, and in caloric value from 84 to 185 kcal per 100 grams. The fatty acids in durian flesh are particularly rich in oleic acid and palmitic acid . The origin of
6840-523: The ICZN for animals and the ICN for plants, do not make rules for defining the boundaries of the species. Research can change the boundaries, also known as circumscription, based on new evidence. Species may then need to be distinguished by the boundary definitions used, and in such cases the names may be qualified with sensu stricto ("in the narrow sense") to denote usage in the exact meaning given by an author such as
6960-466: The Royal Botanic Gardens, Kew , to Auguste Saint-Arroman of Dominica in 1884. In Southeast Asia, the durian has been cultivated for centuries at the village level, probably since the late 18th century, and commercially since the mid-20th century. In My Tropic Isle , Australian author and naturalist Edmund James Banfield tells how, in the early 20th century, a friend in Singapore sent him
7080-399: The fly agaric . Natural hybridisation presents a challenge to the concept of a reproductively isolated species, as fertile hybrids permit gene flow between two populations. For example, the carrion crow Corvus corone and the hooded crow Corvus cornix appear and are classified as separate species, yet they can hybridise where their geographical ranges overlap. A ring species is
7200-498: The jaguar ( Panthera onca ) of Latin America or the leopard ( Panthera pardus ) of Africa and Asia. In contrast, the scientific names of species are chosen to be unique and universal (except for some inter-code homonyms ); they are in two parts used together : the genus as in Puma , and the specific epithet as in concolor . A species is given a taxonomic name when a type specimen
7320-406: The "cynical species concept", and arguing that far from being cynical, it usefully leads to an empirical taxonomy for any given group, based on taxonomists' experience. Other biologists have gone further and argued that we should abandon species entirely, and refer to the "Least Inclusive Taxonomic Units" (LITUs), a view that would be coherent with current evolutionary theory. The species concept
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#17328560186887440-401: The "king of fruits", the durian is distinctive for its large size, strong odour, and thorn -covered rind . The fruit can grow as large as 30 cm (12 in) long and 15 cm (6 in) in diameter, and it typically weighs 1 to 3 kg (2 to 7 lb). Its shape ranges from oblong to round, the colour of its husk from green to brown, and its flesh from pale yellow to red, depending on
7560-570: The 15th century. Translated from the Latin in which Poggio Bracciolini recorded de Conti's travels: "They [people of Sumatra] have a green fruit which they call durian, as big as a watermelon. Inside there are five things like elongated oranges, and resembling thick butter, with a combination of flavours." The Portuguese physician Garcia de Orta described durians in Colóquios dos simples e drogas da India published in 1563. In 1741, Herbarium Amboinense by
7680-509: The Flora of Papua New Guinea that "a feeling of morbidity" often follows the consumption of alcohol too soon after eating durian. Several medical investigations on the validity of this belief have been conducted with varying conclusions, though a study by the University of Tsukuba finds the fruit's high sulphur content inhibits the activity of aldehyde dehydrogenase , causing a 70 percent reduction of
7800-523: The German botanist Georg Eberhard Rumphius was published, providing the most detailed and accurate account of durians for over a century. The genus Durio has a complex taxonomy that has seen the subtraction and addition of many species since it was created by Rumphius. During the early stages of its taxonomical study, there was some confusion between durian and the soursop ( Annona muricata ), for both of these species had thorny green fruit. The Malay name for
7920-555: The Musang King and Monthong varieties in Malaysia and Thailand, respectively, has led to concerns about a decrease in the durian's genetic diversity at the expense of higher-quality varieties. A 2022 study of durian species in Kalimantan , Indonesia, found low genetic diversity, suggestive of inbreeding depression and genetic drift . Additionally, these dominant hybrid varieties are more susceptible to pests and fungal diseases, requiring
8040-573: The Origin of Species explained how species could arise by natural selection . That understanding was greatly extended in the 20th century through genetics and population ecology . Genetic variability arises from mutations and recombination , while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures . Genes can sometimes be exchanged between species by horizontal gene transfer ; new species can arise rapidly through hybridisation and polyploidy ; and species may become extinct for
8160-405: The abbreviation "sp." in the singular or "spp." (standing for species pluralis , Latin for "multiple species") in the plural in place of the specific name or epithet (e.g. Canis sp.). This commonly occurs when authors are confident that some individuals belong to a particular genus but are not sure to which exact species they belong, as is common in paleontology . Authors may also use "spp." as
8280-427: The ability to clear toxins from the body. In its native Southeast Asia, the durian is an everyday food and portrayed in the local media in accordance with the cultural perception it has in the region. The durian symbolised the subjective nature of ugliness and beauty in Hong Kong director Fruit Chan 's 2000 film Durian Durian (榴槤飄飄, lau lin piu piu ), and was a nickname for the reckless but lovable protagonist of
8400-570: The amount of hybridisation is insufficient to completely mix their respective gene pools . A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology , genes can move freely even between distantly related bacteria, possibly extending to the whole bacterial domain. As a rule of thumb, microbiologists have assumed that members of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA–DNA hybridisation to decide if they belong to
8520-494: The annual Malaysian Agriculture, Horticulture, and Agrotourism Show. There are 13 common Malaysian varieties having favourable qualities of colour, texture, odour, taste, high yield, and resistance against various diseases. Musang King (D197) was discovered in the 1980s, when a man named Tan Lai Fook from Raub, Pahang, stumbled upon a durian tree in Gua Musang , Kelantan . He brought a branch back to Raub for grafting. The cultivar
8640-468: The best general idea of it, but there are occasional wafts of flavour that call to mind cream-cheese, onion-sauce, sherry-wine, and other incongruous dishes. Then there is a rich glutinous smoothness in the pulp which nothing else possesses, but which adds to its delicacy." He concluded that it provided a "new sensation worth a voyage to the East to experience. ... as producing a food of the most exquisite flavour it
8760-474: The biological species concept, "the several versions" of the phylogenetic species concept, and the idea that species are of the same kind as higher taxa are not suitable for biodiversity studies (with the intention of estimating the number of species accurately). They further suggested that the concept works for both asexual and sexually-reproducing species. A version of the concept is Kevin de Queiroz 's "General Lineage Concept of Species". An ecological species
8880-505: The biological species concept, a cladistic species does not rely on reproductive isolation – its criteria are independent of processes that are integral in other concepts. Therefore, it applies to asexual lineages. However, it does not always provide clear cut and intuitively satisfying boundaries between taxa, and may require multiple sources of evidence, such as more than one polymorphic locus, to give plausible results. An evolutionary species, suggested by George Gaylord Simpson in 1951,
9000-428: The boundaries between closely related species become unclear with hybridisation , in a species complex of hundreds of similar microspecies , and in a ring species . Also, among organisms that reproduce only asexually , the concept of a reproductive species breaks down, and each clone is potentially a microspecies. Although none of these are entirely satisfactory definitions, and while the concept of species may not be
9120-403: The clusters of fruit within the shell are still crisp in texture and mild in flavour. For some people in northern Thailand , the preference is for the fruit to be soft and aromatic. In Malaysia and Singapore, most consumers prefer the fruit to be as ripe and pungent in aroma as possible and may even risk allowing the fruit to continue ripening after its husk has already cracked open. In this state,
9240-433: The concept of a chronospecies can be applied. During anagenesis (evolution, not necessarily involving branching), some palaeontologists seek to identify a sequence of species, each one derived from the phyletically extinct one before through continuous, slow and more or less uniform change. In such a time sequence, some palaeontologists assess how much change is required for a morphologically distinct form to be considered
9360-416: The concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses ) are given a two-part name , called a "binomial". The first part of a binomial is the genus to which the species belongs. The second part
9480-569: The cultivation of oil palms . Animal species such as the small flying fox , which pollinates durian trees, and the Malayan tiger are endangered by the increasing deforestation of their habitats. In the Gua Musang District , the state government approved the conversion of 40 km (10,000 acres) of forestry, including indigenous lands of the Orang Asli , to durian plantations. The prevalence of
9600-484: The dates for the annual durian fair of Laplae district , and the name given to each cultivar. In 2018, Thailand was ranked the world's number one exporter of durian, producing around 700,000 tonnes of durian per year, 400,000 tonnes of which are exported to mainland China and Hong Kong. Chantaburi in Thailand holds the World Durian Festival in early May each year. This single province is responsible for half of
9720-449: The durian is thought to be in the region of Borneo and Sumatra, with wild trees in the Malay Peninsula , and orchards commonly cultivated in a wide region from India to New Guinea. Four hundred years ago, it was traded across present-day Myanmar, and was actively cultivated especially in Thailand and South Vietnam . The earliest known European reference to the durian is the record of Niccolò de' Conti , who travelled to Southeast Asia in
9840-514: The durian production of Thailand. The Davao Region is the top producer of the fruit in the Philippines, producing 60% of the country's total. In Brunei , consumers prefer D. graveolens , D. kutejensis , and D. oxleyanus . These species constitute a genetically diverse crop source. Durian was introduced into Australia in the early 1960s and clonal material followed in 1975. Over thirty clones of D. zibethinus and six other Durio species have been subsequently introduced into Australia. In 2019
9960-417: The earliest practitioners of that dispersal method, in particular red durian ( D. dulcis ) exemplifying the primitive fruit of flowering plants. However, in more recent circumscriptions of Durioneae, the tribe into which Durio and its sister taxa fall, fleshy arils and spiny fruits are derived within the clade. Some genera possess these characters, but others do not. The most recent molecular evidence (on which
10080-620: The eponymous Singaporean TV comedy Durian King played by Adrian Pang . Likewise, the oddly shaped Esplanade building in Singapore (Theatres on the Bay) is often called "The Durian" by locals, and "The Big Durian" is the nickname of Jakarta , Indonesia. A saying in Malay and Indonesian, mendapat durian runtuh , "getting a fallen durian", is the equivalent of the English phrase ' windfall gain '. Nevertheless, trees bearing mature durians are dangerous because
10200-435: The evidence to support hypotheses about evolutionarily divergent lineages that have maintained their hereditary integrity through time and space. Molecular markers may be used to determine diagnostic genetic differences in the nuclear or mitochondrial DNA of various species. For example, in a study done on fungi , studying the nucleotide characters using cladistic species produced the most accurate results in recognising
10320-415: The flesh becomes richly creamy and slightly alcoholic. The various preferences regarding ripeness among consumers make it hard to issue general statements about choosing a "good" durian. A durian that falls off the tree continues to ripen for two to four days, but after five or six days most would consider it overripe and unpalatable. All the same, some Thais cook such overripe fruit with palm sugar, creating
10440-406: The fruit and dispose of the seed under the parent plant, others swallow the seed with the fruit, and then transport it some distance before excreting, with the seed being dispersed as a result. The thorny, armoured covering of the fruit discourages smaller animals; larger animals are more likely to transport the seeds far from the parent tree. According to Larousse Gastronomique , the durian fruit
10560-420: The fruit came from Thailand, followed by Malaysia and Vietnam. Durian is a relatively costly fruit because of its short shelf life. Shelf life can be extended to around 4 to 5 weeks by shrink wrapping each fruit; this inhibits dehiscence, probably by multiple mechanisms: inhibiting respiration; reducing loss of water; holding the fruit's parts together; and reducing decomposition by microbes. The edible portion of
10680-566: The fruit is heavy, armed with sharp thorns, and can fall from a significant height. Hardhats are worn when collecting the fruit. A common saying is that a durian has eyes, and can see where it is falling, because the fruit supposedly never falls during daylight hours when people may be hurt. In Malaysia, a spineless durian clone D172 was registered by the Agriculture Department in 1989. It was called "Durian Botak" ('Bald Durian'). Sumatran elephants and tigers sometimes eat durians. Being
10800-434: The fruit shape, such as the shape of the spines. The Malaysian Ministry of Agriculture and Agro-Based Industry has since 1934 maintained a list of registered varieties, where each cultivar is assigned a common name and a code number starting with "D". These codes are widely used through Southeast Asia; as of 2021, there were over 200 registered varieties. Many superior cultivars have been identified through competitions held at
10920-414: The fruit, known as the aril and usually called the 'flesh' or 'pulp', only accounts for about 15–30% of the mass of the entire fruit. The strong flavour and odour of the fruit have prompted views ranging from appreciation to disgust. Writing in 1856, the British naturalist Alfred Russel Wallace called the fruit's consistency and flavour "indescribable. A rich custard highly flavoured with almonds gives
11040-509: The fruit. The flesh can be consumed at various stages of ripeness, and it is used to flavour a wide variety of sweet desserts and savoury dishes in Southeast Asian cuisines . The seeds can be eaten when cooked. The name 'durian' is derived from the Malay word duri ('thorn'), a reference to the numerous prickly thorns on its rind , combined with the noun-building suffix -an . According to
11160-409: The head of a fever patient. The most complete description of the medicinal use of the durian as remedies for fevers is a Malay prescription, collected by Burkill and Haniff in 1930. It instructs the reader to boil the roots of Hibiscus rosa-sinensis with the roots of Durio zibethinus , Nephelium longana , Nephelium mutabile and Artocarpus integrifolius , and drink the decoction or use it as
11280-625: The large Indian civet was recorded up to 2,250 m (7,380 ft) in the Himalayas . In China, the wild large Indian civet population declined drastically by 94–99% since the 1950s following deforestation, due to hunting for the fur trade, use of its musk glands as medicine and for the perfume industry. By the 1990s, it was largely confined to the north of Guangdong Province in southern China, but has not been recorded in Hainan Island during surveys between 1998 and 2008. The large Indian civet
11400-431: The lesser short-nosed fruit bat Cynopterus brachyotis , and the large flying fox, Pteropus vampyrus ). Two species, D. grandiflorus and D. oblongus , are pollinated by spiderhunter birds ( Nectariniidae ), while D. kutejensis , is pollinated by giant honey bees and birds as well as by bats. Some scientists have hypothesised that the development of monothecate anthers and larger flowers (compared with those of
11520-508: The most recent, well-supported circumscription of Durioneae is based) therefore refutes Corner's Durian Theory. Since the early 1990s, the domestic and international demand for durian in the Association of Southeast Asian Nations ( ASEAN ) region has increased significantly. In the early 2020s a durian craze in China led to a large increase in international trade of the fruit. A common local belief
11640-586: The neck are banded with black stripes and white spaces in between. The tail has a variable number of complete black and white rings. Its claws are retractable. The soles of the feet are hairy. As indicated by its common name, this is a relatively large civet, almost certainly the largest of the Viverra species and exceeded in size among the Viverridae family only by African civets and binturongs . Its head-and-body length ranges from 50–95 cm (20–37 in) with
11760-478: The numerous fungi species of all the concepts studied. Versions of the phylogenetic species concept that emphasise monophyly or diagnosability may lead to splitting of existing species, for example in Bovidae , by recognising old subspecies as species, despite the fact that there are no reproductive barriers, and populations may intergrade morphologically. Others have called this approach taxonomic inflation , diluting
11880-452: The odour of organosulfur compounds – may be primarily responsible for the distinct odour. Hundreds of phytochemicals responsible for durian flavour and aroma include diverse volatile compounds, such as esters , ketones , alcohols (primarily ethanol ), and organosulfur compounds , with various thiols . Ethyl 2-methylbutanoate had the highest content among esters in a study of several varieties. Sugar content, primarily sucrose , has
12000-585: The paper is accepted for publication. The type material is usually held in a permanent repository, often the research collection of a major museum or university, that allows independent verification and the means to compare specimens. Describers of new species are asked to choose names that, in the words of the International Code of Zoological Nomenclature , are "appropriate, compact, euphonious, memorable, and do not cause offence". Books and articles sometimes intentionally do not identify species fully, using
12120-674: The person who named the species, while the antonym sensu lato ("in the broad sense") denotes a wider usage, for instance including other subspecies. Other abbreviations such as "auct." ("author"), and qualifiers such as "non" ("not") may be used to further clarify the sense in which the specified authors delineated or described the species. Species are subject to change, whether by evolving into new species, exchanging genes with other species, merging with other species or by becoming extinct. The evolutionary process by which biological populations of sexually-reproducing organisms evolve to become distinct or reproductively isolated as species
12240-704: The remaining genera in Durioneae) in the clade consisting of Durio , Boschia , and Cullenia was in conjunction with a transition from beetle pollination to vertebrate pollination. Over the centuries, numerous durian cultivars , propagated by vegetative clones , have arisen in Southeast Asia. They used to be grown, with mixed results, from seeds of trees bearing superior quality fruit, but now are propagated by layering , marcotting , or more commonly, grafting , including bud, veneer, wedge, whip and U-grafting, onto seedlings of randomly selected rootstocks . Different cultivars may be distinguished to some extent by variations in
12360-487: The result of misclassification leading to questions on whether there really are any ring species. The commonly used names for kinds of organisms are often ambiguous: "cat" could mean the domestic cat, Felis catus , or the cat family, Felidae . Another problem with common names is that they often vary from place to place, so that puma, cougar, catamount, panther, painter and mountain lion all mean Puma concolor in various parts of America, while "panther" may also mean
12480-573: The ring. Ring species thus present a difficulty for any species concept that relies on reproductive isolation. However, ring species are at best rare. Proposed examples include the herring gull – lesser black-backed gull complex around the North pole, the Ensatina eschscholtzii group of 19 populations of salamanders in America, and the greenish warbler in Asia, but many so-called ring species have turned out to be
12600-508: The same species. This concept was narrowed in 2006 to a similarity of 98.7%. The average nucleotide identity (ANI) method quantifies genetic distance between entire genomes , using regions of about 10,000 base pairs . With enough data from genomes of one genus, algorithms can be used to categorize species, as for Pseudomonas avellanae in 2013, and for all sequenced bacteria and archaea since 2020. Observed ANI values among sequences appear to have an "ANI gap" at 85–95%, suggesting that
12720-529: The same species. When two species names are discovered to apply to the same species, the older species name is given priority and usually retained, and the newer name considered as a junior synonym, a process called synonymy . Dividing a taxon into multiple, often new, taxa is called splitting . Taxonomists are often referred to as "lumpers" or "splitters" by their colleagues, depending on their personal approach to recognising differences or commonalities between organisms. The circumscription of taxa, considered
12840-676: The seeds are sliced thin and cooked with sugar as a confection. Uncooked seeds are potentially toxic due to cyclopropene fatty acids. Durian fruit is used to flavour a wide variety of sweet edibles such as traditional Malay candy, ice kacang , dodol , lempuk , rose biscuits, ice cream , milkshakes , mooncakes , Yule logs , and cappuccino . Es durian (durian ice cream) is a popular dessert in Indonesia, sold at street side stall in Indonesian cities, especially in Java. Pulut Durian or ketan durian
12960-532: The soursop is durian Belanda , meaning Dutch durian . In the 18th century, Johann Anton Weinmann considered the durian to belong to Castaneae as its fruit was similar to the horse chestnut. D. zibethinus was introduced into Ceylon by the Portuguese in the 16th century and was reintroduced many times later. It has been planted in the Americas but confined to botanical gardens . The first seedlings were sent from
13080-502: The species concept and making taxonomy unstable. Yet others defend this approach, considering "taxonomic inflation" pejorative and labelling the opposing view as "taxonomic conservatism"; claiming it is politically expedient to split species and recognise smaller populations at the species level, because this means they can more easily be included as endangered in the IUCN red list and can attract conservation legislation and funding. Unlike
13200-630: The species name, zibethinus refers to the Indian civet, Viverra zibetha . There is disagreement over whether this name, bestowed by Linnaeus , alludes to civets being so fond of the durian that the fruit was used as bait to entrap them, or to the durian's smelling like the civet. Durian flowers are large and feathery, with copious nectar , and give off a heavy, sour, buttery odour. These features are typical of flowers pollinated by certain species of bats that eat nectar and pollen . Durians can be pollinated by bats (the cave nectar bat Eonycteris spelaea ,
13320-471: The species, cultivars, and localities. A typical durian tree can bear fruit after four or five years. The durian fruit can hang from any branch, and matures roughly three months after pollination . The fruit can grow up to 30 cm (12 in) long and 15 cm (6 in) in diameter, and typically weighs 1 to 3 kilograms (2–7 lb). Its shape ranges from oblong to round, the colour of its husk green to brown, and its flesh pale-yellow to red, depending on
13440-521: The species. Some people regard the durian as having a pleasantly sweet fragrance, whereas others find the aroma overpowering and unpleasant. The smell evokes reactions ranging from deep appreciation to intense disgust. The persistence of its strong odour, which may linger for several days, has led some hotels and public transportation services in Southeast Asia , such as in Singapore and Bangkok , to ban
13560-521: The species. Among the thirty known species of Durio , nine produce edible fruits: D. zibethinus , D. dulcis , D. grandiflorus , D. graveolens , D. kutejensis , D. lowianus , D. macrantha , D. oxleyanus and D. testudinarius . D. zibethinus is the only species commercially cultivated on a large scale and available outside its native region. Since this species is open-pollinated, it shows considerable diversity in fruit colour and odour, size of flesh and seed, and tree phenology . In
13680-400: The species. The leaves are evergreen , elliptic to oblong and 10–18 centimetres (4–7 inches) long. The flowers are produced in three to thirty clusters together on large branches and directly on the trunk, with each flower having a calyx ( sepals ) and five (rarely four or six) petals . Durian trees have one or two flowering and fruiting periods per year, although the timing varies depending on
13800-569: The supposed lecherous quality of this fruit soon spread to the West – the Swedenborgian philosopher Herman Vetterling commented on so-called "erotic properties" of the durian in the early 20th century. The high demand for durians in China has prompted a shift in Malaysia from small-scale durian orchards to large-scale industrial operations. Forests are cleared to make way for large durian plantations, compounding an existing deforestation problem caused by
13920-556: The sweet-like scent of its ketones and esters from rotten or putrescine odours which are from volatile amines and fatty acids . Some individuals are unable to differentiate these smells and find this fruit noxious, whereas others find it pleasant and appealing. This strong odour can be detected half a mile away by animals, thus luring them. In addition, the fruit is highly appetising to diverse animals, including squirrels , mouse deer , pigs, sun bear , orangutan , elephants , and even carnivorous tigers . While some of these animals eat
14040-573: The use of insecticides and fungicides that can weaken the trees. Species A species ( pl. : species) is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring , typically by sexual reproduction . It is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity . Other ways of defining species include their karyotype , DNA sequence, morphology , behaviour, or ecological niche . In addition, paleontologists use
14160-462: The value of imported fresh durian became the highest of all fresh fruits imported to China, which was previously cherries . In 2021, China purchased at least US$ 3.4 billion worth or 90 percent of Thailand's fresh durian exports in that year. Overall Chinese imports grew to $ 4 billion in 2022, when the Philippines and Vietnam gained permission to export fresh durians to China, and $ 6.7 billion in 2023 when 1.4 million tonnes were imported. Durian has become
14280-537: The wild. It is difficult to define a species in a way that applies to all organisms. The debate about species concepts is called the species problem. The problem was recognised even in 1859, when Darwin wrote in On the Origin of Species : I was much struck how entirely vague and arbitrary is the distinction between species and varieties. He went on to write: No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of
14400-447: Was named after its place of origin. The variety has bright yellow flesh and is like a more potent or enhanced version of the D24. It is the preferred cultivar in Singapore and Vietnam. Other popular cultivars in Malaysia include "Tekka", with a distinctive yellowish core in the inner stem; "D168" (IOI), which is round, of medium size, green and yellow outer skin, and easily dislodged flesh which
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