Phasmida (stick and leaf insects)
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Metapterygota > Neoptera > Polyneoptera > Anartioptera > Orthopterida Elongate stick- or leaf-like plant-feeding
insects. The order includes the longest insects in the world, measuring over
half a metre if you include the outstretched legs! .
The Phasmida (stick and leaf insects) are plant-eating
insects often resembling sticks or broad leaves. They do not have their hindlegs
adapted for jumping as in the closely related order
Orthoptera (grasshoppers, katydids, crickets and relatives). Whilst there are about 3000 species, only about 30 are leaf
insects. The classification is covered in the
Phasmida Species File.
In the daytime these typically long, slender stick-like insects remain
remarkably well camouflaged in their habitat, commonly in woodlands, jungle or
gardens. In fact, they may be present in gardens for years without being
noticed. Go out at night with a torchlight and they are then active, walking
about and feeding. Many are not the boring, placid twigs people imagine them to
be. Some species have an amazing range of behaviour, including using spiny legs
in defence, as well as chemical defences. They are prepared to shed a leg in an
effort to escape (capable of re-growing later if the insects are pre-adults). A
number of species are winged in at least one sex – sometimes the wings are
brightly coloured and flashed open to startle a potential predator. In the
absence of males, many species are able to reproduce by parthenogenesis (egg
development without fertilisation) – a handy means of survival.
Eggs are often seed-like in appearance. They are usually dropped onto the
ground, where knobs on the eggs of some species are attractive to certain ants.
Some species glue eggs to branches, or deposit them in crevices. Despite good
camouflage, predators such as birds and animals eat all stages of stick insects;
hence females lay many eggs (over 2000 in some species).
Stick insects are the longest insects in the world:
Species |
Found in |
Maximum
length
from head to end
of body |
Maximum
length
including
outstretched legs |
Record |
Phobaeticus
kirbyi |
Borneo |
328mm |
546mm |
Longest
insect in the world, based on head plus body length. |
Phobaeticus
serratipes |
Malaysia |
278 mm |
555mm |
Longest
insect in the world if you include outstretched legs |
Bactrododema hippotaurum |
Malawi |
263 mm |
|
Longest
insect in Africa. |
Bactrododema krugeri |
South Africa |
226 mm |
|
Longest
insect in South Africa |
Phasmids make excellent pets and are widely seen on display in zoos and
butterfly houses.
Common stick insects of the Cape Town area
Stick insects found in South Africa
A total of 30 species of stick insects have been recorded from South
Africa, with at least nine from the Cape Peninsula (species described from the "Cape of Good Hope" could refer
to anywhere from Cape Town and Grahamstown). Bactricia bituberculata is a sizeable 170mm.
Leaf insects are not found in South Africa, but one species,
Phyllium bioculatum, is well established
in the Seychelles.
Paul Brock has described six new South African species
since 2000. There is considerable scope for enthusiasts to make
studies on stick insects from South Africa – who knows, there may be another new
species just around the corner.
Links
Further reading
-
Brock, P.D. 2000a. Studies of the genus Phalces Stål. Phasmid Studies
8: 1-8.
-
Brock, P.D. 2000b. Stick-insects (Phasmida) from the Cape Town area, South
Africa. Bulletin of the Amateur Entomologists’ Society 59: 2-13, pl. 00A-D.
-
Brock, P.D. 2000c. A Complete Guide to Breeding Stick and Leaf Insects. TFH
Kingdom Books, Havant (ISBN 185279124-1).
-
Compton, S.G. & Ware, A.B.
1991. Ants disperse the elaiosome-bearing eggs
of an African Stick Insect. Psyche 98(2-3): 207-213.
-
Le Feuvre, W.P. 1936. The Stick Insects of the Cape Suburbs. The Cape
Naturalist 1(3): 80-86.
Text by Paul
Brock
|