This is one of the most popular and well-known exotic species. They are a good size attractive ant, with large eyes, long sickle-shaped jaws, and the amazing ability to jump.
This species can be found in southern Asia including Thailand, inhabiting remote undisturbed forested areas. It is classed as a primitive ant and forms small colonies of between 50 to around 200 workers.
They are mostly active during the day, hunting small insects such as spiders, crickets, flies, termites, etc. When they are out hunting and find prey, they have the interesting habit of wagging their gasters, almost as if they are excited about having found their prey. This vibrating action consists of a series of short, rapid, lateral movements, the action of doing this is believed to be the ants assessing the load distribution across its legs in case a hunting jump proves necessary. The workers have very long scythe-shaped jaws, and after seizing their prey quickly deliver a sting, the venom from which renders the victim immobile. It is then taken back to the nest to be consumed, however, if they already have enough food the prey will be left stored in a chamber, frozen by the sting, and eaten at a later date.
Harpegnathos primitive characteristics are also shown in the feeding mechanism. Harpegnathos is a truly predatory ant, with workers feeding exclusively on the hemolymph of their arthropod prey items, and always refusing any type of sugar or nectar diet, as that type of diet only evolved later in the higher ant species. Larvae are highly mobile and are capable of tearing up the prey without the assistance of adult ants.
The workers are between 12 - 15 mm in size and have very large eyes giving them a very good vision for hunting. Vision is very important in this genus. They mostly forage during the daytime and catch their prey by a combination of vision and jumping ability. Their sight is much more acute than most ant species and at times when you are observing them, they will give the intimidating impression that they are staring back and watching you.
They also have the fascinating capability to jump! This action has three purposes: they use this ability to help catch their prey, escape from possible predators, and to attack when their nest is disturbed. The average distance covered in a jump is 8 - 10 cm, nearly ten times their size!
Colonies produce alates of both sexes and these leave the nest to mate, and then the fertilized queens will search for a suitable place to start a colony. They can start a colony on their own or will join together with other founding queens to form a colony together. The new queens are semi-claustral and regularly leave the foundation chamber to forage for food.
This species will also frequently produce gamergates (mated fertilized workers); however, these gamergates are inhibited from laying eggs while a functioning queen is present. If the colonies queen dies then a gamergate will take over the egg-laying. Hence colonies of this species are in effect immortal. Colonies that are headed by gamergates will notably also frequently produce normal winged alates.
Queens are a similar size to the largest workers but can be easily distinguished by their larger sturdier thorax and in their attitude as the leader of the colony, often with subordinate workers facing them in a submissive posture. Adult workers can live up to 1 year, gamergates can live from 1 to 2 years, while queens can live from 3 to 5 years.
They are a ground-nesting species and construct simple nests that are normally found on clay embankments. The single nest entrance usually consists of a very characteristic funnel that is about 3 cm in diameter. This entrance leads to two or three large chambers a short distance beneath the surface. Unusually for ants, their nest entrance is lower than the main nest level, and the ants tend to keep their queens and brood in the higher chambers instead of the lower ones. The reason for this is that in their natural habitat during the rainy season, there are often frequent run-off floods, and as the lower chamber fills with water it traps a bubble of air in the upper chamber, allowing the ants to survive the flooding.
Colonies raise a small amount of brood at a time, which depending on the availability of food and temperature can take two months to mature. The life cycle of Harpegnathos at 25°C from egg to adult takes around 80 days. Eggs may take up to 30 days to hatch, larvae take about 20 days to pupate, and pupae take about 30 days to emerge into adult ants.
In captivity their nest enclosure should ideally be kept between 24 - 28°C, however, in the winter months, the night temperature can be allowed to fall to 15°C for short periods. They like humid conditions inside their nest of around 70 - 80% RH, but in providing this humidity try and avoid condensation droplets. Ideally, their foraging area should follow the conditions of their natural habitat and be humid at night, but less so during the day.
We find they respond well in artificial nests with access to a natural landscaped foraging area. The ideal foraging area should have a shallow layer of humus-type base medium, and be landscaped with some small branches, a few pieces of bark, and some dead leaves. Food can simply be dropped into the area and the ants will enjoy hunting for it as they would in their natural wild habitat. They do not like and will not respond well to the bare plastic/acrylic setups sold by some vendors.
They prefer small live insects to feed on, but because colonies are not large do not need a lot of food. A good measure of whether to feed or not is to observe the workers. If the workers are all inside the nest, then they probably have enough food – if many workers are outside in the foraging area it is time to feed them.
Although most information given on this species states they will only take live insects, we have found that they will readily take dead insects when hungry, both complete small insects or cut up larger insects. However, these should be freshly killed. This action makes them a bit easier to keep as if you only have larger size food available you can cut it up to feed them.
Summary: They are a good-sized ant, have big impressive mandibles, very good vision, and the amazing ability to jump. For hobbyists with experience in keeping exotics this species unique body structure and interesting actions make them a novel and must-have addition to collections.
However, because of their preference for live food, required environmental conditions, and the fact that colonies grow in size slowly - they are not recommended for beginners to the hobby.