Extatosoma tiaratum
Encyclopedia
Extatosoma tiaratum is a large species
of stick insect endemic to Australia
.
The species has the Phasmid Study Group
number PSG9.
and New South Wales
but has extralimital distribution as far away as New Guinea
.
Female adult E. tiaratum are covered with thorn-like spikes for defense and camouflage
. Their long, rounded bodies grow to about 8 inches (20 cm) long. The females are further described as "heavy-bodied, brachypterous
and (having) numerous spines and integumental expansions on the body and legs, including a tuft of spines on the conical occiput
of the hypognathous head". As mentioned, the wings of the female are too small for flying
, especially when she is gravid
.
Exhibiting the sexual dimorphism
of many similar insects (particularly other phasmid
s as well as mantis
es), males are small and thinner, growing only about 11 cm in length and have three ocelli. Males lack the thorny growths except for spikes around their heads. They have long wings
and are good flyers who readily take to the air if disturbed or in search of females.
Both genders, when threatened, stand on the front and middle legs, pointing their abdomen
up or to the side in a sort of "scorpion
" pose. They fold back their legs to defend themselves if anything comes in contact with their abdomen. Adult males can release a defensive odor that humans might not find offensive as it "is rather reminiscent of peanut butter
or toffee
".
E. tiaratum also take a curved pose when it hangs inverted amongst foliage with "its highly procryptic
abdomen curled over its back." Like many stick insects, E. tiaratum sway back and forth or side to side when disturbed. They also move this way to blend with foliage rustling in the wind. Individual E. tiaratum vary in color and appear brown, mottled brown, dun, green, a reddish color, a cream color, a yellowish color, and even entirely white.
E. tiaratum typically reproduce through sexual reproduction
and produce egg
s that hatch four months later. When no males are present in the population, this stick insect exhibits parthenogenesis
instead. Eggs laid without fertilization take up to nine months to hatch and produce only females. In either cases, the female "flicks" her eggs, swinging her tail, up to several feet to land on the forest floor. These eggs must be kept relatively cool - under 25°C - or they are unlikely to hatch.
The outside material of E. tiaratum eggs consists of lipid
s and other organic compound
s that ant
s identify as food. They carry these eggs to their colony
, consume the edible outer portion, and dump the intact eggs into their waste piles. Luckily for captive breeding, the ants eating the edible outer layer is not crucial to development, so they will hatch just as healthy without the need for any removal of the outer layer, which is not easily visible.
Newly-hatched E. tiaratum nymphs
are ant mimics
and resemble the insects in whose nest they are born. Their aposematic pattern—orange head, white collar, the rest black—mimics the ant genus Leptomyrmex
and makes them appear toxic. Although most adult stick insects are notoriously slow, these nymphs are speedy, active, and quickly make their way to the trees. Their locomotion
slows when they moult
into their second and subsequent instar
s. Female acquire their distinctive spiky appearance through additional moults as well.
, kept as project in school
s (as is Carausius morosus
), and is popular pet
among breeders of exotic insects in North America
and Europe
. One breeder advises specifically "For a stick insect with body length 127mm, to keep 2 adult females, you need a cage at least 600mm high, 300mm deep and 300mm wide."
Although the gestation
period of their eggs is several months long, they are prolific breeders. A breeder notes that because of this insect's habit
of flicking its eggs, one can "hear them clicking against the glass" of their terarria. Some breeders in the United Kingdom
, concerned with the negative effects of inbreeding
on the vitality of their stock
, have introduced new gene
s from abroad.
, eucalyptus
(their natural food in their native Australia), hawthorn
, oak
, photinia
, raspberry
, rose
, and salmon berry (red or yellow). One source reports good results from feeding these insects California Wax Myrtle
(Myrica californica) as the sole food plant.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of stick insect endemic to Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
The species has the Phasmid Study Group
Phasmid Study Group
The Phasmid Study Group is a group for professional and amateur entomologists who are interested in the order Phasmatodea, as well as other interested persons. Over 40 species of Phasmid have been named after members of the group....
number PSG9.
Range
E. tiaratum is native to QueenslandQueensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
and New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
but has extralimital distribution as far away as New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
.
Description
Camouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...
. Their long, rounded bodies grow to about 8 inches (20 cm) long. The females are further described as "heavy-bodied, brachypterous
Brachypterous
Brachyptery is an anatomical condition meaning that an animal has very reduced, non-functional wings. Such as animal may be described by the adjective "brachypterous"....
and (having) numerous spines and integumental expansions on the body and legs, including a tuft of spines on the conical occiput
Occiput
The occiput is the anatomical term for the posterior portion of the head, in insects the posterior part of those head capsule.-Clinical significance:Trauma to the occiput can cause a basilar skull fracture....
of the hypognathous head". As mentioned, the wings of the female are too small for flying
Insect flight
Insects are the only group of invertebrates known to have evolved flight. Insects possess some remarkable flight characteristics and abilities, still far superior to attempts by humans to replicate their capabilities. Even our understanding of the aerodynamics of flexible, flapping wings and how...
, especially when she is gravid
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
.
Exhibiting the sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
of many similar insects (particularly other phasmid
Phasmatodea
The Phasmatodea are an order of insects, whose members are variously known as stick insects , walking sticks or stick-bugs , phasmids, ghost insects and leaf insects...
s as well as mantis
Mantis
Mantis is the common name of any insect in the order Mantodea, also commonly known as praying mantises. The word itself means "prophet" in Latin and Greek...
es), males are small and thinner, growing only about 11 cm in length and have three ocelli. Males lack the thorny growths except for spikes around their heads. They have long wings
Insect flight
Insects are the only group of invertebrates known to have evolved flight. Insects possess some remarkable flight characteristics and abilities, still far superior to attempts by humans to replicate their capabilities. Even our understanding of the aerodynamics of flexible, flapping wings and how...
and are good flyers who readily take to the air if disturbed or in search of females.
Both genders, when threatened, stand on the front and middle legs, pointing their abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
up or to the side in a sort of "scorpion
Scorpion
Scorpions are predatory arthropod animals of the order Scorpiones within the class Arachnida. They have eight legs and are easily recognized by the pair of grasping claws and the narrow, segmented tail, often carried in a characteristic forward curve over the back, ending with a venomous stinger...
" pose. They fold back their legs to defend themselves if anything comes in contact with their abdomen. Adult males can release a defensive odor that humans might not find offensive as it "is rather reminiscent of peanut butter
Peanut butter
Peanut butter is a food paste made primarily from ground dry roasted peanuts, popular in North America, Netherlands, United Kingdom, and parts of Asia, particularly the Philippines and Indonesia. It is mainly used as a sandwich spread, sometimes in combination as in the peanut butter and jelly...
or toffee
Toffee
Toffee is a confection made by caramelizing sugar or molasses along with butter, and occasionally flour. The mixture is heated until its temperature reaches the hard crack stage of 300 to 310 °F...
".
E. tiaratum also take a curved pose when it hangs inverted amongst foliage with "its highly procryptic
Crypsis
In ecology, crypsis is the ability of an organism to avoid observation or detection by other organisms. It may be either a predation strategy or an antipredator adaptation, and methods include camouflage, nocturnality, subterranean lifestyle, transparency, and mimicry...
abdomen curled over its back." Like many stick insects, E. tiaratum sway back and forth or side to side when disturbed. They also move this way to blend with foliage rustling in the wind. Individual E. tiaratum vary in color and appear brown, mottled brown, dun, green, a reddish color, a cream color, a yellowish color, and even entirely white.
Reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
and produce egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
s that hatch four months later. When no males are present in the population, this stick insect exhibits parthenogenesis
Parthenogenesis
Parthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...
instead. Eggs laid without fertilization take up to nine months to hatch and produce only females. In either cases, the female "flicks" her eggs, swinging her tail, up to several feet to land on the forest floor. These eggs must be kept relatively cool - under 25°C - or they are unlikely to hatch.
The outside material of E. tiaratum eggs consists of lipid
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
s and other organic compound
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
s that ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
s identify as food. They carry these eggs to their colony
Ant colony
An ant colony is an underground lair where ants live, eat and mate. Colonies consist of a series of underground chambers, connected to each other and the surface of the earth by small tunnels. There are rooms for nurseries, food storage, and mating...
, consume the edible outer portion, and dump the intact eggs into their waste piles. Luckily for captive breeding, the ants eating the edible outer layer is not crucial to development, so they will hatch just as healthy without the need for any removal of the outer layer, which is not easily visible.
Newly-hatched E. tiaratum nymphs
Nymph (biology)
In biology, a nymph is the immature form of some invertebrates, particularly insects, which undergoes gradual metamorphosis before reaching its adult stage. Unlike a typical larva, a nymph's overall form already resembles that of the adult. In addition, while a nymph moults it never enters a...
are ant mimics
Ant mimicry
Ant mimicry is mimicry of ants by other organisms. Ants are abundant all over the world, and insect predators that rely on vision to identify their prey such as birds and wasps normally avoid them, either because they are unpalatable, or aggressive. Thus some other arthropods mimic ants to escape...
and resemble the insects in whose nest they are born. Their aposematic pattern—orange head, white collar, the rest black—mimics the ant genus Leptomyrmex
Leptomyrmex
Leptomyrmex is a genus of ants. According to the latest taxonomic revision, there are 27 extant and one fossil species . For a complete list of species and full references, see here...
and makes them appear toxic. Although most adult stick insects are notoriously slow, these nymphs are speedy, active, and quickly make their way to the trees. Their locomotion
Animal locomotion
Animal locomotion, which is the act of self-propulsion by an animal, has many manifestations, including running, swimming, jumping and flying. Animals move for a variety of reasons, such as to find food, a mate, or a suitable microhabitat, and to escape predators...
slows when they moult
Moult
In biology, moulting or molting , also known as sloughing, shedding, or for some species, ecdysis, is the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life cycle.Moulting can involve the epidermis , pelage...
into their second and subsequent instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
s. Female acquire their distinctive spiky appearance through additional moults as well.
Cultivation
This species is relatively common in captivity. It is used in laboratoriesLaboratory
A laboratory is a facility that provides controlled conditions in which scientific research, experiments, and measurement may be performed. The title of laboratory is also used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories...
, kept as project in school
School
A school is an institution designed for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is commonly compulsory. In these systems, students progress through a series of schools...
s (as is Carausius morosus
Carausius morosus
Carausius morosus is a species of phasmid that is often kept by schools and individuals as pets. Culture stocks originate from an original collection from Tamil Nadu, India. Like the majority of the phasmatodea, they are nocturnal. Culture stocks are parthenogenetic females that can reproduce...
), and is popular pet
Pet
A pet is a household animal kept for companionship and a person's enjoyment, as opposed to wild animals or to livestock, laboratory animals, working animals or sport animals, which are kept for economic or productive reasons. The most popular pets are noted for their loyal or playful...
among breeders of exotic insects in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. One breeder advises specifically "For a stick insect with body length 127mm, to keep 2 adult females, you need a cage at least 600mm high, 300mm deep and 300mm wide."
Although the gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....
period of their eggs is several months long, they are prolific breeders. A breeder notes that because of this insect's habit
Habit (biology)
Habit, when used in the context of biology, refers to the instinctive actions of animals and the natural tendencies of plants.In zoology, this term most often refers to specific behavioral characteristics, even when directly related to physiology...
of flicking its eggs, one can "hear them clicking against the glass" of their terarria. Some breeders in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, concerned with the negative effects of inbreeding
Inbreeding
Inbreeding is the reproduction from the mating of two genetically related parents. Inbreeding results in increased homozygosity, which can increase the chances of offspring being affected by recessive or deleterious traits. This generally leads to a decreased fitness of a population, which is...
on the vitality of their stock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
, have introduced new gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
s from abroad.
Diet
E. tiaratum are vegetarians and breeders recommend feeding them bayberry, brambleBramble
Brambles are thorny plants of the genus Rubus, in the rose family . Bramble fruit is the fruit of any such plant, including the blackberry and raspberry. The word comes from Germanic *bram-bezi, whence also German Brombeere , Dutch Braam and French framboise...
, eucalyptus
Eucalyptus
Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...
(their natural food in their native Australia), hawthorn
Crataegus
Crataegus , commonly called hawthorn or thornapple, is a large genus of shrubs and trees in the rose family, Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. The name hawthorn was originally applied to the species native to northern Europe,...
, oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
, photinia
Photinia
Photinia is a genus of about 40-60 species of small trees and large shrubs in the Rosaceae family. As interpreted here, they are restricted to warm temperate Asia, from the Himalaya east to Japan and south to India and Thailand, but some botanists also include the closely related North American...
, raspberry
Raspberry
The raspberry or hindberry is the edible fruit of a multitude of plant species in the genus Rubus, most of which are in the subgenus Idaeobatus; the name also applies to these plants themselves...
, rose
Rose
A rose is a woody perennial of the genus Rosa, within the family Rosaceae. There are over 100 species. They form a group of erect shrubs, and climbing or trailing plants, with stems that are often armed with sharp prickles. Flowers are large and showy, in colours ranging from white through yellows...
, and salmon berry (red or yellow). One source reports good results from feeding these insects California Wax Myrtle
Myrica californica
Myrica californica Myrica californica Myrica californica (California Bayberry, California Wax Myrtle or Pacific Wax Myrtle; syn. Gale californica (Cham. & Schltdl.) Greene, Morella californica (Cham...
(Myrica californica) as the sole food plant.