Phasmids
- Leaf and Stick Insects
There
are more than 2,500 species of leaf and stick insects, of which
some half dozen species are regularly encountered in captivity.
Glasgow
Zoopark has maintained several species at one time or another, including
the Indian Stick Insect, Macleays Spectre, Pink Winged Stick,
and Thailand Stick
As
their name suggests, most species camouflage themselves as twigs
or leaves, with colouring varying from browns
to greens. Many are able to vary their
colouration to suit their surroundings should this change. Some
- usually the males - are able to fly. The wings are quite attractively
patterned. Large varieties of stick insects are impressive with
body lengths exceeding 15 cms.
Flight
is sometimes used to aid escape. Some species drop to the ground
and feign death. Others emit an offensive odour or chemical, whilst
others possess spines, or a sharp hooked claw. Allgrowing insects
shed; or moult, their skins. From hatching to maturity most shed
about five times. If a leg is lost, a new, usually slightly inferior
one will regenerate.
Phasmids
are interesting to keep in captivity. The Common, or Indian
Stick Insect prefers a dry atmosphere, and will live happily
in a cage consisting of a wooden framework covered with fine mesh.
Other species prefer a more humid atmosphere, so a tank with a peat
base is more suitable. The tank should at least be large enough
for the insect to hang suspended from a branch whilst shedding.
If
the insects have a food plant to hang onto whilst you clean the
tank, or glass, then they usually remain in position and don't move
around. Catching adults and/or juvenils repeatedly leads to accidents,
escapes and injuries.
Most
species will eat several species of fairly accessible plants, and
trial and error will confirm these for your own particular insects.
Privet is the food for the Indian Stick, fresh, young Bramble
for the Macleay's Spectre. Try and ensure you know where supplies
(in sheltered pockets, will keep growing through the winter!)
Provided
the room is kept at an average temperature in the mid- 60 degrees
farenheit, no extra heating is necessary, though some species live
and breed more successfully at higher temperatures. Most are happy
anywhere between 65-80 degrees farenheit. If the temperature falls
dramatically at night a 40 watt heat lamp is recommended.
Some
species are parthenogenic - females produce fertile eggs without
having mated with a male i.e. the Pink Winged Stick. Others
mate in the normal manner. If the eggs are left in the cage, the
babies hatch after 2-3 months and easily escape through cracks,
or drown in the water used in the container keeping the food plants
alive, so the necks should be neatly plugged with cotton wool.
If
you remove the eggs, remember to label and date them accurately,
to help you accurately anticipate likely hatching times.
Looking
After Stick Insects
-
Bottom of cage: Line with newspaper. Do NOT clean out, as eggs
lie there, which will in due time hatch.
- Twigs
of privet: Stand in water. Water jar to be blocked around twigs
with paper or a rag, so that nymphs (young stick insects) cannot
drown. In water, the privet twigs remain fresh for quite a long
time.
- Watch
out for round gnaw marks, which means they are feeding.
- Indian
stickies die at about 15 months of age, so do NOT distress yourselves
at the sight of the occasional dead body. Twigs of privet MUST
stand upright in a cage higher than bottom area.
Indian
Stick Insects
It almost
goes without saying that these creatures should have freshly picked
privet available at all times. Preferably, this should be renewed
one a daily basis. In reality, one suspects that the majority of pet
owners, after a few months, grow a little tired of what can seem a
tedious routine. ‘Replenishment’ becomes an every two or
three day routine, or whenever the leaves have wilted or been eaten.
From our own observations, one increasingly gains the impression that
this restricts egg production, rather as one witnesses in some other
arid area animals in response to harsh conditions. We also increasingly
feel that if you do not ‘harvest’ the excess offspring,
that the consequent overcrowding also reduces reproductive success
and survival of the very young stages. Of course, maximising the production
of Indian sticks is often the last thing most people want to do, usually
it’s the reverse.
However, during 1999 we have given away several hundred young sticks
to schools and individuals from a cage measuring no more than 30 cms
square. When the young are removed on a gradual, but regular, basis
and the adults kept copiously supplied with fresh privet it is just
amazing how fast they increase in numbers again.
Despite the fact that many young people and quite a few adults have
kept these creatures, one wonders how closely people actually observe
or watch them. The written accounts in books and journals do not begin
to suggest just how interesting the behaviour of Indian stick insects
can be.
Most people are given the impression that their lives consist of avoiding
predation by looking like sticks, and obviously this is important.
However, stick insects are ‘adventurous’ and relatively
fast moving! If they think they have been ‘spotted’ they
will take - especially the sub-adults - active avoiding action. They
will ‘hide’ on the opposite side of a branch or twig to
the perceived danger. If a strong light (like lighting for a photograph
or filming) is shone on them, they will all move to the underside
of leaves, or at least into shadow. Finally, all stick insects, except
for very large adults, will exhibit mimicry if they feel threatened,
curling their tail over their backs ‘scorpion-style’.
In the West of Scotland at any rate, if not elsewhere, many first-time
owners seem to have the totally erroneous impression that these creatures
can eat either brambles or privet. We find that if people appear here,
having kept Indian stick insects before ‘but they died’,
nine times out of ten, it is because they tried to feed them on bramble!!
It cannot be emphasised too strongly that they only eat privet, which
brings us onto another point.
Privet is a poisonous shrub, packed with tannins. Could the scorpion-like
behaviour of the younger individuals be a ‘double safety’
designed to deter birds and other predators before the toxic residues
in their bodies have had a chance to accumulate fully? The large,
old adults must be extremely unpalatable, if not dangerous, to most
small predators.
Finally, how many owners have witnessed a stick insect shedding its
skin? If not, why not? If they are on every pupil’s shelf in
his or her bedroom, one would have thought the opportunities for close
observation would have been maximised. The process can been speedy,
taking only about ten minutes. The insect hangs from a twig. Once
out it eats its skin, then the legs, appearing to suck them in from
where they were attached to the body, as if eating a stick of rock.
After completing the eating of the skin the stick insect then walks
to an open area - usually the glass of its tank - to sit, immobile,
for several house whilst its new skin hardens, after which the serious
business of eating privet leaves starts all over again. Eating the
old skin, thus, ‘buys it time’ to rest and harden its skin. |
