''Acropyga acutiventris'' is an

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

in the subfamily

Formicinae The Formicinae are a subfamily within the Formicidae containing ants of moderate evolutionary development. Formicines retain some primitive features, such as the presence of cocoons around pupae, the presence of ocelli in workers, and littl ...

. It lives underground in tropical regions and forms a mutualistic association with the

mealybug Mealybugs are insects in the family Pseudococcidae, unarmored scale insects found in moist, warm habitats. Of the more than 2,000 described species, many are considered pests as they feed on plant juices of greenhouse plants, house plants and ...

, '' Xenococcus annandalei''.

Description

This ant has the small eyes, compact body and yellowish-brown colouration typical of many ants that live underground.myrmecos.net
It can be separated from other Formicine ants found in Australia by the fact that the antennae have eleven segments, the eyes are multifaceted and clearly defined, and the first and second funicular segments are the same size.Nomenclature and distribution of some Australian and New Guinean ants of the subfamily Formicinae
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Distribution

This ant is found in

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

s in tropical regions of

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

Sarawak Sarawak ( , ) is a States and federal territories of Malaysia, state of Malaysia. It is the largest among the 13 states, with an area almost equal to that of Peninsular Malaysia. Sarawak is located in East Malaysia in northwest Borneo, and is ...

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...

Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...

and parts of the

Northern Territory The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an states and territories of Australia, Australian internal territory in the central and central-northern regi ...

and

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

in Australia. In Australia it is not usually found above 300 metres and occupies a similar range to the

weaver ant Weaver ants or green ants are eusocial insects of the Hymenoptera family Formicidae belonging to the tribe Oecophyllini. Weaver ants live in trees (they are obligately arboreal) and are known for their unique nest building behaviour where wor ...

, ''

Oecophylla smaragdina ''Oecophylla smaragdina'' (common names include Asian weaver ant, weaver ant, green ant, green tree ant, and orange gaster) is a species of tree, arboreal ant found in tropical Asia and Australia. These ants form colonies with multiple nests in ...

''.

Biology

This ant lives in association with the mealybug, '' Xenococcus annandalei'' in its underground

nest A nest is a structure built for certain animals to hold Egg (biology), eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of ...

. The mealybug is a subterranean species and sucks sap from the rootlets of certain trees, particularly species of ''

Ficus ''Ficus'' ( or ) is a genus of about 850 species of woody trees, shrubs, vines, epiphytes and hemiepiphytes in the family (biology), family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few spe ...

'' and the

coconut palm The coconut tree (''Cocos nucifera'') is a member of the palm tree family (biology), family (Arecaceae) and the only living species of the genus ''Cocos''. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, ...

. It exudes drops of honeydew which form part of the diet of the ant. Worker ants tend the mealybugs and stimulate the production of honeydew by stroking their abdomens. If the ant colony is disturbed and the ants are forced to disperse, each takes a female mealybug to the new nest site, carrying it in her

mandibles In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

. When the soil is warm and damp, the ants and mealybugs remain just below the surface, but during cold, dry weather they descend to greater depths. This mutualistic arrangement seems to occur throughout the range of the ant. ''X. annandalei'' has not been found anywhere except in association with ''A. acutiventris'' in its nest, and while being transported by the queen who carries a female mealybug on her

nuptial flight Nuptial flight is an important phase in the reproduction of most ant, termite, and some bee species. It is also observed in some fly species, such as '' Rhamphomyia longicauda''. During the flight, virgin queens mate with males and then land ...

. The colony she founds is thus provided with the food supply it needs to prosper. No other means of dispersal is known for this mealybug.

References

{{Taxonbar, from=Q3645496 Formicinae Hymenoptera of Australia Hymenoptera of Asia Insects of India Insects of China Invertebrates of Hong Kong Insects of Malaysia Insects of Indonesia Insects of Singapore Insects of Vietnam Insects of Papua New Guinea Insects of Queensland Arthropods of the Northern Territory Insects described in 1862 Taxa named by Julius Roger