walkingstick n : any of various mostly tropical insects having long twiglike bodies [syn: walking stick, stick insect]

"Phasmid" redirects here. For the cloning vector used in genetics, see phagemid.

The Phasmatodea (sometimes called Phasmida) are an order of insects, whose members are variously known as stick insects (in Europe), walking sticks or stick-bugs (in the United States of America), phasmids, ghost insects and leaf insects (generally the family Phylliidae). The ordinal name is derived from the Greek "phasma" meaning an apparition or phantom, and refers to the resemblance of many species to sticks or leaves. A few species (e.g. Anisomorpha) are capable of secreting a substance from glands on the metathorax that can cause an intense burning irritation of the eyes (and in some cases temporary blindness) and mouth of potential predators on contact.

Taxonomy

The classification of the Phasmatodea is complex. There are many people, including amateur entomologists, studying the order, and revisions are commonplace. The most authoritative source for information on the current taxonomy is the Phasmida Species File which is continually updated.

The Phasmatodea were considered a suborder of Orthoptera, although most authors now consider them to form an order of their own. There is much confusion over the ordinal name, with Phasmida being preferred by many authors, although it is incorrectly formed. Phasmatodea is correctly formed, and is gaining in popularity. Cheleutoptera is now considered outdated.

They are sometimes considered related to other orders, including the Blattaria, Mantodea, Notoptera and Dermaptera, but the affiliations are uncertain and the grouping (sometimes referred to as "Orthopteroidea") may be paraphyletic and hence invalid in the traditional circumscription.

Species

There are around 2,500 described species, with many more yet to be described, both in museum collections, and in the wild. The order has a world-wide distribution, but most species are found in the tropics. These species vary from stick like species to those resembling bark, leaves and even lichens.

Stick insects as pets

Many stick insects are easy to care for, and make good pets. The Indian (or Laboratory) stick insect, Carausius morosus, requires a tall (25+ cm) vivarium (even a jar with a few holes punched in the top), some bramble, ivy, privet and lettuce and an atmosphere at room temperature. Indian stick insects are all female and reproduce by parthenogenesis and seem content living on their own. Occasionally part-male part-female individuals are reared in captivity, but never true males. The stick insects molt and may eat the shed skin. By the sixth molt the stick insect will lay eggs.

Notable species

One Australian species, the Lord Howe Island stick insect, is now listed as critically endangered. It was believed extinct until its rediscovery on the rock known as Ball's Pyramid. There is a large effort in Australia to rear this species in captivity.

Females of the genus Phobaeticus are the world's longest insects, measuring up to 33 cm (13 in) from head to tip of abdomen.

Adult female Heteropteryx dilatata are likely to weigh up to 65 g, and captive bred specimens have been known to weigh in the order of 50 g.

The best known of the stick insects is the Indian or Laboratory stick insect (Carausius morosus). These insects grow to roughly 10 cm (4 inches). They reproduce parthenogenically and males are unrecorded, although part male part female gynandromorphs are relatively common.

Breeding

To breed stick insects, spray the eggs with water lightly and wait for them to hatch. Use a paint brush to handle the young nymphs. Take care not to leave pools of water where they could drown. If the egg is still attached to the insect's tail then gently pull off with paint brush.

References

• Cameron, Stephen L.; Barker, Stephen C. & Whiting, Michael F. (2006): Mitochondrial genomics and the new insect order Mantophasmatodea. Molecular Phylogenetics and Evolution 38: 274–279. (HTML abstract)

External links

• The Phasmid Study Group
• Phasmatodea.org
• Phasmatodea.de
• Phasmida Species File
• New Zealand Stick Insect Web Site
• Le Monde des Phasmes - The World of Phasmids