''Euprenolepis procera'' is a species of
ant
Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22 ...
found in the
rainforest
Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...
s of
South East Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...
.
It was first
described by
Carlo Emery
Carlo Emery (25 October 1848, Naples – 11 May 1925) was an Italian entomologist. He is remembered for Emery's rule, which states that insect social parasites are often closely related to their hosts.
Early in his career Carlo Emery pursue ...
, an Italian
entomologist
Entomology () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arach ...
, in 1900. In 2008, Witte & Maschwitz discovered that ''E. procera'' specialises in harvesting
mushroom
A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans.
The standard for the name "mushroom" is t ...
s in the rainforest for food, representing a new, previously unreported feeding strategy in ants.
[
]
Distribution
''Euprenolepis procera'' is endemic to South East Asia, being found in the rainforests of Malaysia
Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...
, Thailand
Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...
and Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
.[ In Malaysia, where they have been studied, individual colonies were recorded to occur at a density of one nest per approximately 150 m2, but Witte & Maschwitz stated this may be an underestimate as they may not have discovered some colonies.][
]
Taxonomy
This species was first described in 1900 by Carlo Emery
Carlo Emery (25 October 1848, Naples – 11 May 1925) was an Italian entomologist. He is remembered for Emery's rule, which states that insect social parasites are often closely related to their hosts.
Early in his career Carlo Emery pursue ...
, under the name ''Prenolepis procera'';[ Emery based his description on material collected by the Italian anthropologist ]Elio Modigliani
Elio Modigliani (13 June 1860 – 6 August 1932) was an Italian anthropologist, zoologist, explorer, and plant collector.
Biography
The son of a Florentine banker, he first made his name in the Italian scientific community at the age of 20, wh ...
in his travels in Malesia
Malesia is a biogeographical region straddling the Equator and the boundaries of the Indomalayan and Australasian realms, and also a phytogeographical floristic region in the Paleotropical Kingdom. It has been given different definitions. The ...
. Emery assigned the species to the subgenus ''Euprenolepis'' in 1905, and moved that subgenus to the genus ''Paratrechina
''Paratrechina'' is one of seven ant genera (alongside ''Euprenolepis, Nylanderia, Paraparatrechina, Prenolepis, Pseudolasius,'' and ''Zatania'') in the ''Prenolepis'' genus-group from the subfamily Formicinae (tribe Lasiini). Six species are ...
'' in 1925. In 1995, Bolton raised the subgenus to the rank of genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
, giving the species its current name.[
In 1913, ]Auguste-Henri Forel
Auguste-Henri Forel (1 September 1848 – 27 July 1931) was a Swiss myrmecologist, neuroanatomist, psychiatrist and eugenicist, notable for his investigations into the structure of the human brain and that of ants. For example, he is considered ...
described a new species, ''Camponotus (Myrmosphincta) antespectans'', which was also moved to ''Euprenolepis'' by Emery. This is now considered a synonym
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
of ''E. procera''.[
]
Description
Workers
The workers are polymorphic, consisting of a minor (body length = ) and major caste
Caste is a form of social stratification characterised by endogamy, hereditary transmission of a style of life which often includes an occupation, ritual status in a hierarchy, and customary social interaction and exclusion based on cultura ...
(body length = ); the major caste is relatively rare compared to the minor caste. The workers' heads are heart-shaped, broader than they are long and a "dark-reddish brown" colour. The antennae of both worker castes are made up of twelve segments and are a lighter colour than their heads, their mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
s have five teeth. The major workers superficially resemble species of ''Pseudolasius
''Pseudolasius'' is a genus of ants in the subfamily Formicinae. The genus is known from southern Asia (from India to China) to northern Australia, where it appears to be restricted to tropical
The tropics are the regions of Earth surround ...
''.[
]
Reproductive castes
The queen
Queen or QUEEN may refer to:
Monarchy
* Queen regnant, a female monarch of a Kingdom
** List of queens regnant
* Queen consort, the wife of a reigning king
* Queen dowager, the widow of a king
* Queen mother, a queen dowager who is the mother ...
s and male
Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization.
A male organism cannot reproduce sexually without access to ...
s have larger eyes than the workers, and also have three pronounced simple eyes as well. The queens are covered in a dense layer of hairs. The antennae of the males are made of thirteen segments, unlike twelve in workers, and their mandibles have only one well-developed tooth. The queens are a similar colour to the workers, but have mottled areas that are a lighter colour than the rest of the body.[
]
Behaviour
''Euprenolepis procera'' is nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
, only foraging for food at night, venturing up to from the nest, but on average around . It lives in colonies of between 500 and 50,000 individuals, forming nests inside preformed cavities, rather than constructing nests themselves. They migrate regularly, staying in each location for between one and nine days; these migrations are thought to be necessary as the colony quickly depletes available food near its nest. Similar adaptations to unpredictable food resources are common to all harvester ants, but only seen in two other types of ant: army ant
The name army ant (or legionary ant or ''marabunta'') is applied to over 200 ant species in different lineages. Because of their aggressive predatory foraging groups, known as "raids", a huge number of ants forage simultaneously over a limi ...
s which migrate into new foraging areas and ''Dolichoderus
''Dolichoderus'' is a genus of ants found worldwide.
Taxonomy
The ants of the Neotropical genus ''Monacis'' were revised in 1959 by Kempf. However, Brown in 1973 and G. C. Wheeler and J. Wheeler in 1973 and 1976 considered both ''Monacis'' and ' ...
'' transport their trophobiont mealybug
Mealybugs are insects in the family (biology), family Pseudococcidae, unarmored scale insects found in moist, warm habitats. Many species are considered pest (animal), pests as they feed on plant juices of greenhouse plants, house plants and sub ...
s to parts of plants that are growing.[
]
Feeding
Over 200 species of ants are known to eat fungi as a major part of their diet, but these ants in the Attini tribe
The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English language, English is in the discipline of anthropology. This definition is contested, in p ...
have co-evolved with fungi, forming a mutualism that benefits both the fungus and the ants. Unlike similar ants found in the New World
The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. 3 ...
, ''E. procera'' does not cultivate fungi in its nest, but instead harvests the sporocarp of fungi (mushrooms) from the rainforest in which it lives as its primary source of food. It is the only species of ant known to have such a feeding habit.[ When it was first reported in 2008, ]Bert Hölldobler
Berthold Karl Hölldobler (born 25 June 1936) is a German sociobiologist and evolutionary biologist who studies evolution and social organization in ants. He is the author of several books, including ''The Ants'', for which he and his co-author, ...
, an expert on ants, called the discovery "sensational" and said "nothing like that was known before". They have been observed to eat over 30 species of mushroom, but they also ignore 50 species present in their habitat; of those that they do eat, the mushrooms often occurred near the roots of trees, indicating that mycorrhizal
A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, mycorrhiza or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plan ...
fungi form part of their diet. During field observations only two occurrences of them feeding on animals (a grasshopper
Grasshoppers are a group of insects belonging to the suborder Caelifera. They are among what is possibly the most ancient living group of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago.
Grasshopp ...
and a snail
A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastro ...
) were recorded, compared to 266 mushrooms which were consumed. In a laboratory study, colonies thrived for over thirteen weeks on a diet consisting only of '' Pleurotus'' and ''Agaricus
''Agaricus'' is a genus of mushrooms containing both edible and poisonous species, with over 400 members worldwide and possibly again as many disputed or newly-discovered species. The genus includes the common ("button") mushroom (''Agaricus bisp ...
'' mushrooms. Thus, the natural diet is believed to consist almost entirely of mushrooms. Feeding experiments demonstrated that they are able to live off a diet of honey or insects as well.[
Once they locate mushrooms which they consider edible in the wild, they harvest them efficiently, removing over 70% of the mushroom within four hours. In a laboratory study, they almost completely harvested a ''Pleurotus'' mushroom that weighed within three hours. Once they have harvested the mushrooms, they transport pieces of them back to their nest and arrange them into piles in diameter. Over time these piles turn from white to black, losing mass as workers continuously chew and feed on the fungi and in turn feed the ant ]larvae
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
. The pulp has a distinctive sweet-sour odour which may be due to fermentation
Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...
occurring. This food processing continues for around a week, depending on the size of the original pile of pieces. If the fungal material is kept away from the ants it quickly spoils, becoming infested by bacteria and smelling unpleasant, but when processed by the ants no spoiling has been observed. The exact mechanisms of the processing of fungi are under investigation.[
They are thought to have evolved this feeding habit because few other animals eat mushrooms and therefore there is little ]competition
Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indivi ...
for the food resource. When mushrooms were placed near nests of ''E. procera'' they were by far the main consumer of the mushrooms with other animals barely feeding on them.[
]
Ecological significance
The effects that harvesting of mushrooms by ''E. procera'' has on the ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
is currently unknown. They may have similar effects as ants that harvest seeds of plants, by changing the relative abundance of different fungal species.[
]
References
{{Taxonbar, from=Q4038297
Formicinae
Insects described in 1900
Hymenoptera of Asia