Stick insects, along with leaf insects, belong to the order Phasmida, and are collectively referred to as "Phasmids." This is a large family; there are over 2500 species of stick and leaf insects. These insects rely primarily on camouflage as a defense, so look either very much like like twigs or leaves, depending on the species. Only some species of stick insect are winged. Most come from tropical climates.
These insects are among the most popular insects kept as pets due largely to their unique appearance and the relative ease of caring for them. The care of the various species depends on their native environment (i.e. humidity, temperature, and food sources). The key to keeping stick insects in captivity is to try to mimic the conditions they would naturally experience and feed them foliage as close to what they naturally eat as possible. Stick insects can be handled and can be quite tame, but they are fragile and must be handled with the utmost of care.
Stick Insects as Agricultural Pests
Non-native stick insects should never be released into the wild due to the risk that they could reproduce and cause damage to an ecosystem where they are not normally found; non-native species are considered plant pests. This includes making sure any eggs are disposed of by crushing, boiling, or burning, as no special care is needed for many species' eggs to hatch. If you are in the United States or Canada, tropical species such as the Indian Walking sticks are considered plant pest and a permit (United States Department of Agriculture or Canadian Food Inspection Agency) is required to import them. In other areas, check with the appropriate government agency about legality (e.g. a Department of Agriculture or similar agency).
Indian stick insects (Carausius morosus) have been kept in captivity for years, especially in the United Kingdom. They have a unique appearance and are relatively easy to care for. They reach a length of up to 4 inches (10 cm), and their expected lifespan is approximately one year.
A Suitable Home
As a rule, stick insects need an enclosure that is three times as tall as the length of the insect. For Indian stick insects, this means a minimum of 12 inches tall, although a little taller would be better. Glass aquaria (10 to 15 gallon), tall glass jars, plastic pet containers, and other similar containers work well for housing, but the lid needs to be well ventilated and secure to prevent escapes. Fine netting can be fixed over the opening to such containers.
Indian stick insects should be kept fairly warm, around 70 to 75 F (21 to 24 C). The temperature can be allowed to decrease a bit at night to mid to high 60s F. The best way to achieve the proper temperature is to keep them in a warm room, although supplementary heat can be provided through head pads meant for reptile enclosures or by placing a lamp near the cage. Using lamps for heat can be very drying, and white bulbs should not be used at night (red or blue colored bulbs can be used).
If using potted plants in the vivarium, consider using a fluorescent fixture above the vivarium for optimal plant growth.
Stick insects need a moderate level of humidity, but the vivarium should be well ventilated to prevent mold growth. Misting the leaves of the plant will provide water for the insects to drink and help maintain humidity levels.
The floor of the tank can be covered with paper for easy cleanup. An alternative material that helps conserve humidity is peat moss or vermiculite. This takes a bit more effort to keep clean, and shouldn't be kept too moist since mold growth could be a problem. Stick insects produce a fairly dry waste which is easy to clean up.
Bramble (blackberry) is generally considered an appropriate diet for many stick insects. Other options include raspberry, privet, hawthorn, oak, rose, and ivy. Fresh cut branches of these plants can be placed in water in the cage and changed once they dry out (or are consumed). The water container must be closed off or sealed so that the insects do not fall into the water and drown (choose a narrow-necked jar and place some material around the plant stems to seal off the opening). An alternative to feeding cut branches is to grow small potted plants of the desired species and place them in the cage.
The most important thing to consider is that any food must be free of insecticides and herbicides, or it may be lethal to your pets. Care must be taken when collecting food to make sure it hasn't been exposed to these materials. Try to avoid collecting food near busy roadways. Even if using potted plants, make sure that the soil used is free of pesticides, as some soils are infused with pesticides which may make their way into plants grown in the soil.
Handling Stick Insects
Handle with care! Stick insects tend to be quite tame so will sit on your hand, but care must be taken when picking them up or handling them. Very carefully grasp them by the body (not the legs!) between your thumb and forefinger and place them on your open palm, or simply offer your open palm and gently nudge them onto your hand.
Indian stick insects can reproduce in the absence of a male (parthenogenetic reproduction). A female will lay hundreds of tiny (0.08 inch or 2 mm) eggs over her life. These are smooth and round and can be collected from the bottom of the cage if desired. Place them in a tub of sand or vermiculite and leave in a warm place. They may take up to a year to hatch, and they should be kept in small separate rearing containers until they reach adulthood when they can be housed in small groups (similar environment to adults, feed a fresh supply of leaves often).
The babies ("nymphs") molt several times before reaching adulthood, and during this process, they will hang suspended from a branch or the lid of the container. Molting is an extremely vulnerable time in development, and the insects should be left alone and not handled until the new exoskeleton is hardened after a molt.