Acropyga acutiventris is an ant

Ant

Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

 in the Formicinae

Formicinae

Formicinae is 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 little tendency toward reduction of palp or antennal segmentation in...

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

Mealybug

Mealybugs are insects in the family Pseudococcidae, unarmored scale insects found in moist, warm climates. They are considered pests as they feed on plant juices of greenhouse plants, house plants and subtropical trees and also acts as a vector for several plant diseases.-Distribution:Mealybugs...

, Xenococcus annandalei

Xenococcus annandalei

Xenococcus annandalei is a species of mealybug in the family Pseudococcidae that infests the roots of certain species of trees.-Description:...

.

Description

This ant has the small eyes, compact body and yellowish-brown colouration typical of many ants that live underground. It can be separated from other Formicine ants found in Australia by the fact that the antennae

Antenna (biology)

Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....

 have eleven segments, the eyes are multifaceted and clearly defined, and the first and second funicular segments are the same size.

Distribution

This ant is found in rainforest

Rainforest

Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...

s in tropical regions of India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, Hong Kong

Hong Kong

Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...

, Malaysia, Sarawak

Sarawak

Sarawak is one of two Malaysian states on the island of Borneo. Known as Bumi Kenyalang , Sarawak is situated on the north-west of the island. It is the largest state in Malaysia followed by Sabah, the second largest state located to the North- East.The administrative capital is Kuching, which...

, Singapore

Singapore

Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...

, Vietnam

Vietnam

Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

, Papua New Guinea

Papua New Guinea

Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...

 and parts of the Northern Territory

Northern Territory

The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...

 and Queensland

Queensland

Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

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

Weaver ant

Weaver ants or Green ants are eusocial insects of the family Formicidae . Weaver ants are obligately arboreal and are known for their unique nest building behaviour where workers construct nests by weaving together leaves using larval silk...

, Oecophylla smaragdina

Oecophylla smaragdina

Oecophylla smaragdina is a species of arboreal ant found in Asia and Australia. They make nests in trees made of leaves stitched together using the silk produced by their larvae.Weaver ants may be red or green...

.

Biology

This ant lives in association with the mealybug, Xenococcus annandalei

Xenococcus annandalei

Xenococcus annandalei is a species of mealybug in the family Pseudococcidae that infests the roots of certain species of trees.-Description:...

in its underground nest

Ant colony

An ant colony is an underground lair where ants live, eat and mate. Colonies consist of a series of underground chambers, connected to each other and the surface of the earth by small tunnels. There are rooms for nurseries, food storage, and mating...

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

Ficus

Ficus is a genus of about 850 species of woody trees, shrubs, vines, epiphytes, and hemiepiphyte in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending into the semi-warm temperate zone. The Common Fig Ficus is a genus of...

and the coconut palm

Coconut

The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...

. It exudes drops of honeydew

Honeydew (secretion)

Honeydew is a sugar-rich sticky liquid, secreted by aphids and some scale insects as they feed on plant sap. When their mouthpart penetrates the phloem, the sugary, high-pressure liquid is forced out of the gut's terminal opening. Honeydew is particularly common as a secretion in the Hemipteran...

 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. 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

Nuptial flight is an important phase in the reproduction of most ant, termite and some bee species. During the flight, virgin queens mate with males and then land to start a new colony, or, in the case of honey bees, continue the planned succession of an existing hived colony.- Before the flight :A...

. 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.