Leaf insects are a fascinating type of camouflaging insect in the stick insect order, Phasmatodea. Gray’s Leaf Insect, Phylliium bioculatum, is just one species of this group of master camouflagers. Gray’s Leaf Insect belongs specifically to the terrestrial, Phylliidae family. The insect is said to be endemic to the Seychelles Islands and West Maylasia; however, the insect has also been recorded in Borneo, China, India, Java, Singapore, Sumatra, Madagascar, Mauritius, and other parts of South East Asia. Gray’s Insects are fairly easy to breed and can be breed in different locations by bug enthusiasts.
These leaf insects, also referred to as Javanese Leaf Insects and Seychelles Leaf Insects, were first described by George Robert Gray in 1832. Leaf insects have changed little over time based on a 47 million year old fossil similar to the modern day leaf insect. They prefer tropical areas and rainforests. For proper development, they need a humid environment. These bugs are characterized by their irregular body, leg, and wing shape (similar to that of a leaf), 2 dots on their abdomen, and green, yellow, orange, or red (as nymphs) coloration.
Gray’s Leaf Insect is classified as (LC) least concern by the IUCNRed List due to it’s restricted range and low density. The cause of this insect’s rarity is unknown, though. One hypothesis for the rarity is predation by alien, newly introduced species to the leaf insect’s habitat.
The life expectancy of female and male Gray’s Leaf Insects differ greatly. The females have an estimated lifespan of 4 to 7 months while the males only live an average of 3 weeks to 1 month. The insect develops via hemimetabolous lifecycle with egg to nymph to adult stages and 5-6 molts. The females can produce more than 300 eggs over a lifetime, averaging 2-3 eggs per day. The female can use asexual reproduction to produce only female offspring with a longer incubation time or sexually to produce males with a shorter incubation time. The eggs hatch in 5-7 months via asexual reproduction or in 3-4 months via sexual reproduction. The insects emerge from the eggs as tiny red colored nymphs. Once the nymphs begin to feed their coloration changes to green in 3 to 7 days
The terrestrial Gray’s Leaf Insect is a herbivore. Its diet can consist of mango, guava, cherry, dewberry, raspberry, blackberry, oak, bramble, and Rambutan. Gray’s Insect is sometimes named by the type of food it eats. Kept in captivity, many noted feeding the insect blackberry and raspberry leaves.
According to the observation of some Pylliium bioculatum breeders, the insects are hard to handle. The males are capable of flight and can easily lose legs. The females have wings but lack a specific part of the wing for flight. After fertilization, spermatophores can be observed on the females.
Like many organisms in the stick insect order, Gray’s Leaf Insects, are slow moving. They continuously rely on their leaf-like appearance, leaf mimicry, for protection from predators like birds. The insects rock back and forth when walking to mimic a leaf blowing in the wind. Their appearance can even mimic bite marks in leafs and veins similar to those of local plants in its habitat.
(Example of Gray’s Leaf Insect’s behavior, walk and care)