Oecophylla smaragdina
This well-known species constructs its nests from leaves, held together by strands of silk woven by its larvae.
The workers are an attractive bright orange color and very variable in size. The smaller minim workers only measure 3 - 4 mm and these stay inside the nest taking care of the queen and brood. There are also many forms of minor workers, and in time as the colony grows large major workers/soldiers are produced, and these do the hunting and defend the colony. The large majors can be 12 mm in size and are armed with powerful mandibles. They are aggressive strong ants and will vigorously attack anything they find within their territory. Their color serves as a warning to predators that they are dangerous.
The new queens are 20 mm and found colonies independently. They start their nests in a single curled leaf, and once the young colony is established, it will increase in size quickly, and within 3 - 4 years the mature nests can be the size of a football. Colonies only have a single queen and can have up to 500,000 workers. Mature colonies will construct several large sub-nests scattered amongst all the nearby trees. These sub-nests are used to store excess food and provide a source of quick worker recruitment when potential food is found nearby.
Their favorite food seems to be the sweet secretions from sap-sucking insects living on the trees, but they also vigorously hunt other insects, and larger colonies will frequently forage across the ground near the base of the trees.
Finding new queens of this species is very difficult as they don’t have mass swarms like normal ants, are not found on the ground after their flights, and are not attracted to artificial lights. The difficulty in finding new queens has made this one of the most frequently scammed species we know. It is common knowledge amongst the ant trade that collectors of this species are shipping ‘queens’ that are in reality female alates that have had their wings removed. These cheap so-called queens are being shipped in large numbers to sellers in Europe and elsewhere. Some unscrupulous end-sellers/retailers are then brood boosting them to give the impression that they are young established colonies. We have seen this happen with at least one seller in the UK who buys in these infertile queens, then gives them brood from an established stock colony, before selling them on. Infertile queens will even lay eggs giving the impression of being young queens, but the eggs will never mature or will be eaten at a later date.
All the queens we offer for sale are collected by myself and kept until they have raised their first brood to ensure they are fertile. All this takes time and the queens are only found in small numbers so they are priced accordingly, but you can be sure that our foundation colonies have young, vigorous, fertile queens.
In captivity, they are best housed in a setup that mimics their natural environment. Good results have been obtained keeping them in a tall aquarium landscaped with natural plants and several small branches. They will not accept the usual artificial nests in which many other species are kept.
Summary: An attractive aggressive ant with an unusual nesting strategy.
However, only recommended for experienced hobbyists as they are difficult to maintain in captivity and very aggressive.
Note: Colonies are difficult to establish from just queens, frequently failing in the early stages. With this in mind we recommend that you avoid the cheap offers available for single queens, and whenever possible choose an option with workers.
Foundation perils in the wild.
Foundation perils in the wild.
After mating day flights, the fertile queens go in search of a suitable plant to start a colony. Their first hurdle is to find a plant that is acceptable. They will not attempt to found a colony on an unsuitable plant. Shrubs/trees that have smooth leaves that are easily bent are preferred and an already slightly curled leaf is ideal. The aspect of the foundation site is also important as it needs to be out of direct sunlight and situated low down to minimize the effects of strong winds.
Another hurdle is finding a tree that is not already the territory of another ant species. Ants in the tropics are widespread and utilize every available food source, and trees with their numerous sap suckers, etc. are usually already the territory of other ant species. It may take a queen several days to find a suitable location and, in that time, she is using up precious food reserves.
Once she has selected a safe place she settles down and sheds her wings, and then her first action is to rough up the surface of the leaf by scouring it with her feet and mandibles, presumably this is to give her a good grip. The next stage is very dangerous as she now lays her eggs and has to stand guard over them on an open exposed leaf. Predators such as spiders, other ants, and small birds will all eat the queens. Weather is also an important factor regards colony foundation as strong storms lash the forests at the start of the rainy season with winds bending the branches and pounding the trees with heavy rain.
Things only start to improve when the queen’s first larvae emerge. She uses these to exude silk and she slowly but surely seals herself into a spider-like enclosure without any entrance. This offers some protection in hiding her from predators and now the likes of spiders cannot get to her.
Other perils at this time include the changing aspect of the sun or broken branches which expose her leaf to strong light. A sealed queen can quickly die of heat before she can escape and her sealed chamber can become her tomb.
She must wait about four/five weeks before the first workers emerge. Brood development is highly dependent on temperature and at 25°C it takes 38/40 days for the first workers to emerge, while if it is slightly warmer at 30°C it takes only 28 days. At 25°C Eggs hatch in 10/11 days and the larvae pupate after a further 12/13 days with the first workers emerging 16 days later.
A good queen can raise a first brood of about twenty–thirty workers. These stay inside with the queen for several days then open up a small hole in the webbing to venture out. It is essential now they can find some food as the colony is at its weakest, having not had any sustenance for over a month. The priority is to raise a creditable workforce as fast as possible. It becomes essential for a colony to expand, defend its territory, and protect its food source.
Often several new queens will select the same tree to start their colony. In this situation, the first workers to emerge will attack the competing foundation colonies, and kill the other competing queens and steal their brood. These young colonies will wage war at a very early stage often when they only have ten-plus workers. They are fighting for the establishment and survival of their colony.
Sometimes several queens will join together to found a colony. However, although this results in a larger stronger first brood being raised, once the first few workers have emerged, the queens will viciously fight for dominance with the loser being ejected from the nest.
When the first workers emerge, they will spend about a week to acclimatize and strengthen and not leave their leaves. Then they will open up a small hole and start to explore. Although this species is active both day and night the early workers will only venture out in the safety of darkness. They need to explore their new territory and quickly find food, protecting it against potential threats.
The first workers are all the same size and are classed as minors. They are not the small minims or the large majors. This caste size performs all the colony’s duties, caring for the queen and brood, expanding the nest, and foraging.
After the second follow-on brood emerges the colony tends to move further up in the tree to take advantage of the higher light levels and warmth. This is another dangerous time and is usually done in the early hours of the morning. A large queen walking along a branch is a tasty morsel for many creatures such as lizards, birds, and spiders. A quick gulp by a gecko would be the end of the colony.
Although at this early stage the workers are able to protect the colony from smaller predators such as spiders, young colonies with only a few dozen workers can be devastated by the nightly visits of geckos or a single attack from a small bird.
If they can survive the first 4 - 6 months the colony will then be several hundred strong and they will be using two or three leaves to make their nest. Within a year will have a nest the size of a clenched fist, and from this stage onwards they expand very quickly.