Giant water bugs make fascinating pets for aquarium and insect hobbyists. These ferocious insects attack and eat fish, tadpoles, salamanders, snails, and other insects and watching them ambush and hunt prey is amusing, although they do not need to be fed often. Giant water bugs are excellent swimmers and accomplished fliers. Most species can survive periods of temperatures lower than 32F and above 90F. Adults can live up to five years as pets and the ferocious water bug Abedus herberti makes the best pet of all the giant water bugs. It not only fares well in captivity but also is easy to rear. The following article details the rearing of A.herberti.

The giant water bugs - family Belostomatidae - contains about two hundred species from around the world. The family Belostomatidae is in the Order Hemiptera or true bugs. All giant water bugs have paddle-shaped hind legs for swimming and raptorial front legs for catching prey. They also have a flat oval-shaped body, and range in colour from blackish-brown to yellowish-tan. Members of the Belostomatidae range in adult size from 15mm (3/5 inch) to 100mm (4 inches). The ferocious water bug Abedus herberti is a medium to large member of this family and ranges from 35-45mm in length. The body is relatively wider than most of the other species in the family.

A.herberti can inflict painful bites to humans, but they are not aggressive and do not bite unless handled carelessly. Nymphs do not appear to bite, even when handled carelessly. The bite is reported to inflict a minor venom, like a bee sting, and some digestive enzymes. Any person with severe allergies should be careful with any biting arthropod but water bug bites do not pass on any diseases.

Ferocious water bugs begin life as eggs. Unlike many insects, whose eggs are abandoned by the adults, A.herberti eggs are glued to the surface of the male‘s tegmina (outer wings) and the adult males care for and protect the eggs until they hatch. Eggs removed from the male‘s back do not hatch. There are many smaller species of Abedus in which males also carry the eggs. Other large types of water bugs, such as Lethoceros, glue their eggs to emergent vegetation and adults tend to eat them. In spite of this many do manage to survive without adult care. In captivity it is important not to have excessive emergent areas in the cage, as crickets being introduced as food will sometimes walk unnoticed onto the males back and eat the eggs.

Tiny nymphs hatch eighteen days (at 75 degrees Fahrenheit) after being laid. The hatchlings look and act like miniature adults but do not have wings. If they are kept at seventy-five degrees Fahrenheit, and with constant feeding, the nymphs will molt every eight days. The final molt takes twenty-one days, and two days prior to this molt the wingpads turn very dark. The young will stay healthy and grow well, even if fed only every week or two, but animals fed as sparingly as this will grow more slowly and become slightly smaller adults.

Nymphs molt (shed their old skins) while in the water and they need something to hang on to whilst completing the process. A percentage of nymphs will die during moults as a direct result of a lack of suitable surfaces being available. Styrofoam pieces and rocks do not work well, instead sticks placed in the water are a much more suitable alternative. The best surface of all, however, can be provided by pieces of the aquatic plant Java moss, although pieces of dead sphagnum moss might conceivably work nearly as well as Java moss if the latter is difficult to obtain.

Hatchlings have voracious appetites and nymphs will feed on a variety of tiny aquatic arthropods, such as Daphnia, small fish (such as baby guppies), tubifex worms and small snails. Nymphs will also feed on unrealistically large insects which are dropped into the water. Adult crickets and mealworms will be accepted, despite being as much as fifty times the mass of a hatchling. Frozen crickets are also accepted. The only drawback of feeding large insects to the nymphs is the risk that the remains could easily foul the water. For this reason it is important to remove any uneaten food or waste matter shortly after feeding, certainly within a few hours.

Adult A.herberti can be kept together, as they do not kill one another unless they have been severely starved over a period of months. Although adults do not eat one another, adults will eat nymphs and nymphs will feed on one another. Nymphs must, therefore, be reared separately and the easiest way to do this is to keep them in disposable cups with a few inches of water in the bottom (see above photograph). The nymphs cannot climb smooth surfaces and will be unlikely to escape. Nymphs which have recently become adults have very soft shells and are in this state very vulnerable. It is, therefore, important to allow two weeks for the new exoskeleton to harden before new adults are placed with others. In the soft-shelled state the insects may be killed.

A.herberti can be kept in any aquarium, or watertight container, and they do not seem to be concerned whether they are kept in a few inches or a few feet of water. Planted aqua-terrariums make beautiful cages, but a bucket with a few inches of water works just as well, if not as aesthetically pleasing. Although keeping them with tropical fish is ill-advised for the aquarist (and presumably for the fish), the interaction between the fish and ferocious water bugs can be fun to watch. There are two major considerations when choosing housing: 1. As Abedus can fly, a lid is a necessity. 2. Abedus cannot climb smooth-sided containers but they easily climb tubing and cords, so any fixtures and fitting must be suitably covered.

Water quality is not as great a concern as it would be for many aquatic animals, but the issue must still be addressed. Hardness, pH, and contaminants seldom, if ever, affect Abedus and filtration is unnecessary. Fouled water can be poured out and replaced straight from the tap, without causing any ill-effects. Although nymphs and adults take air from the surface, they also store air under the abdomen. If the water is severely fouled, the insects will use up all the oxygen in the stored air and the bugs will spend much time spent constantly replenishing their air supply. Conversely, in clean, well aerated water long periods are spent without coming to the surface as the bugs are able to subsist on their stored air.

Adults tend to survive even in the dirtiest of water, but nymphs are more sensitive and foul water can kill them. Fouled water also often has a greasy film over the top, which can prevent nymphs from breaking the surface tension and getting new air. During the moulting process this can drown them.

In my opinion the ferocious water bug is among the neatest and most fascinating of all the insect pets. The ease of care and breeding of this animal promises to keep it in the hobby. Hopefully this article will not only help those interested in this species but also inspire new keepers to try this great bug.