Stick insects are also known as phasmids, meaning ghosts, because of the way in which they blend into their surroundings, thanks to their camouflage. Most are green or brownish in colour, but their powers of mimicry extend far beyond simply blending in with the background. Blow gently on a young stick insect holding on to a branch and watch as to how it moves, just like a leaf does in the breeze.
The Indian or laboratory stick insect (Carausius morosus), which is the most commonly-kept species, is very easy to cater for, although it is important to bear in mind that these stick insects can reach an adult size of 15cm (6in) when adult, and so they need reasonably spacious surroundings at this stage. If they are overcrowded, they may nibble each other's legs.
Young hatchlings, however, can be kept in smaller sizes of plastic containers with ventilated hoods, provided that they cannot slip out through gaps in the roof of the vivarium, as they are very agile at this stage. Wrapping a layer of fine black cloth just below the hood will serve to keep them adequately confined here.
Height is the most important feature in terms of vivarium design for many stick insects. It is especially important that the height of their enclosure is such that they can hand vertically downwards so they can moult without difficulty. You will also need to incorporate suitable lengths of bramble here both as food and to allow them to clamber around the branches.
If touched by hand, adults will generally fall to the floor, folding their legs along their bodies so that they effectively appear to be a green piece of twig. After some minutes, once they judge the danger to have passed, they will stand up and clamber back on to a convenient branch. Indian stick insects never normally descend to the floor of their quarters, although recently-hatched young may sometimes move around here.
Rather than having to cut fresh bramble every day, which can become hard to find during the winter months in any case, the simplest solution is to stand stems in a container of water, stuffing the neck here with tinfoil to stop any young stick insects falling in and drowning.
The bramble can then be changed when it starts to shrivel up or once its leaves have been chewed away by the stick insects.
Floor covering and egg-laying
The floor covering in the quarters of young stick insects can be bark, which creates an attractive effect, although in the case of mature egg-laying individuals, then plain white paper towelling is to be recommended. This will enable you to spot their eggs easily. They resemble seeds, usually being dark in colour, and so would be almost impossible to pick out among bark.
On a sheet of paper, it is also easy to separate the eggs from the stick insects' droppings, allowing them to be collected without difficulty. The eggs can simply be rolled off the paper, thanks to their relatively rounded shape.
Sexing Indian stick insects for breeding purposes is unnecessary, because female lay fertile eggs without the need to mate - a process called parthenogenesis. Males are actually very rare, being recognisable by their smaller size and red underside to their thorax. Mating is not normally observed, even when a male does crop up.
Cleaning their quarters
Do not be fooled by the sluggish appearance of stick insects however, when it comes to cleaning their quarters. Always transfer them to a secure container rather than simply leaving them on a branch alongside the vivarium. Otherwise, they will frequently react to this change in environment by seeking to scamper away quickly, and their camouflage then makes them difficult to retrieve.
A small plastic carrying vivarium is useful for this purpose. While tiny hatchlings can be transferred on a clean tip of a paintbrush, larger individuals can be lifted by fingers placed either side of the thorax. When touched however, stick insects do tend to cling on tightly with their feet and these may have to be prised off the branch beforehand, because otherwise, you could injure the invertebrate.
Down on the ground
Contrary to popular belief though, not all stick insects live off the ground. The best-known example is the giant spiny stick insect (Eurycantha calarata), which originates from New Guinea and neighbouring islands. This is a terrestrial form of stick insect, with a broad, relatively flattened body which rarely shows any inclination to climb. A close-up of its head is shown above (picture).
Giant spiny stick insects require a covering of bark on the floor, and suitable retreats in the form of cork bark where they can hide. As befits a species which lives mainly on the ground, these stick insects will eat grass, as well as other vegetation. They may also drink from a shallow container of water.
Out and about
Stick insects do not necessarily need to be confined in a vivarium, depending on your home surroundings. It is quite possible to house larger species such as the giant prickly (Extatostoma tiaratum) which originates from northern Australia, on large bramble shoots put in a vase, and stood in a quiet part of a room, with a spotlight above to provide some additional heat if required.This will also highlight the insects themselves.
Especially once mature, they will not wander far, with the larger females usually being quite content to clamber through the branches, although males may occasionally take short flights on their wings. A tray beneath will serve to collect the droppings easily, but you are likely to find that females lay their relatively large eggs with such propulsive force that these may land several feet away, even on the other side of the room.
There is therefore no single way in which to accommodate stick insects successfully in the home, and it is something which needs to be considered carefully from the outset, with larger accommodation being needed as they grow older. Female giant prickly stick insects may reach a length of 20cm (8in) when mature, having been less than 2.5cm (1in) long on hatching.
Heating and lighting
It is not normally necessary to heat the quarters of Indian stick insects, as they can be maintained quite successfully at room temperature, but other species do prefer slightly warmer surroundings. This can be achieved quite easily by means of a heat pad, fixed to the rear of their quarters, where it will emit gentle heat, rather like a radiator. For terrestrial species, this is more valuable than having a pad on the floor beneath the vivarium.
Lighting will help to highlight the stick insects in their vivarium, but be sure that they cannot burn themselves, and do not allow the temperature in the vivarium to become uncomfortably hot and dry for them. Low relative humidity will otherwise cause them to have difficulty in moulting successfully.
Whereas Indian stick insects generally live for just over a year or so, the giant species have a longer life expectancy, particularly in the case of females, which may extend to three years. But beware of using household chemicals in their vicinity - especially fly or flea sprays - which are likely to be toxic.