PHYLLIUM BIOCULATUM
PULCHRIFOLIUM
( MALE )

CLEAR RESIN ENCAPSULATION

PHASMID STUDIES (PDF)

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Phylum Arthropoda

Class Insecta

Order Phasmatodea

Family Phylliidae

Genus Phyllium

Species Phyllium Bioculatum

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The family Phylliidae (often misspelled Phyllidae) contains the extant true leaf insects or walking leaves, which include some of the most remarkably camouflaged leaf mimics in the entire animal kingdom. They occur from South Asia through Southeast Asia to Australia. At present, there is no consensus as to the preferred classification of this group; some sources treat Phylliidae as a much larger taxon, containing the members of what are presently considered to be several different families.

Leaf insects are camouflaged (using mimicry) to take on the appearance of leaves. They do this so accurately that predators often are not able to distinguish them from real leaves. In some species the edge of the leaf insect's body even has the appearance of bite marks. To further confuse predators, when the leaf insect walks, it rocks back and forth, to mimic a real leaf being blown by the wind.

The Gray's leaf insect, (Phyllium Pulchriphyllium bioculatum), is a leaf insect of the family Phylliidae native to west Malaysia. It was first described by George Robert Gray in 1832, which was his first phasmid he discovered. Leaf insects have extremely flattened, irregularly shaped bodies, wings, and legs. They are usually about 5-10 cm long (2-4 in long). They are called leaf insects because their large, leathery forewings have veins that look similar to the veins on the particular type of leaves they inhabit. Its Polish name is li?ciec dwuoki, which comes from the two dots located on the abdomen just in this species,as does the scientific name (bioculatum meaning ''two-eye'').

Description

A closer view of a male P. bioculatum with its visible wings (note also the two namesake dots) The insect has green, broad body and legs and frequently has spots. Both females and males occur in shades of green, yellow, and orange. Java leaf insects would be greenish or brownish as adults. Males range from 66 to 94 mm. The organism's fore wings and camouflage are used for defense. The antennae of the females are very short, while those of the male are longer. Adult females are 46-69 mm in length. The species also has hind wings which are used for flying by males, but are unused by females. Young Phyllium bioculatum are about 2 cm long, dark red in colour and have reflex immobility. The species molts 5-6 times in a lifetime. Females are heavy-bodied and flightless, and each lays about 500 eggs in a lifetime. The abdomen is narrower at the base, and the femur of the fore legs are dilated.

Ecology

They are slow-moving herbivores and rely on their camouflage and fore wings for defense from predators including birds, amphibians and reptiles. The females live from 4 to 7 months and males from 3 weeks to 1 month.

Habitat

These leaf insects are found mainly in tropical areas and rainforests where adequate quantities of vegetation are available for consumption. It is widespread in Southeast Asia, in Borneo, China, India, Sri Lanka, Java, Malaysia, Singapore, and Sumatra. It is also found in Madagascar, Mauritius, and the Seychelles.

The preferred temperature for this species is 24-28 C (75-82 F), which at night may slightly decrease by 2-3 C (3.6-5.4 F). Temperature does not strongly affect the species but will slow development. It is important that the temperature is not reduced below 22 C (72 F). Low humidity can cause stress and death.

Diet

As a herbivore Phyllium bioculatum mainly eats mango, guava, Nephelium lappaceum , and in captivity some accept Quercus & Rubus (dewberry, raspberry and blackberry) species.

Reproduction and incubation

The females lay eggs in months. Incubation takes place from 5-7 months at 25 C (77 F). Eggs are beige-brown and about 6-7 mm .

However, many times the eggs laid are not fertilized due to parthenogenesis. This is a form of asexual reproduction found in females, where growth and development of embryos occurs without fertilization by a male. Eggs are oval or barrel-shaped, like seeds. Different types of oviposition occurs in leaf insects. The eggs of this species are catapulted by a backward movement of the abdomen. In a study the ratio of the distance the egg was thrown and the bodylength of the insect was compared with some other species, which was 24-36. If the eggs are fertilized, then it takes 3-4 months for incubation, otherwise it takes 6 months for unfertilized eggs. Unfertilized eggs hatch out with females only, while fertilized ones may be either male or female. The female lays about 100 eggs at intervals of a few days. The larvae are red at hatching but green within three to seven days. These hatch from eggs laid at a rate of three per day per female.