Back to Biodiversity Explorer main pageGo to Iziko Museums of Cape Town home pageAbout Biodiversity Explorer - history, goals, etc.Send us your questions about southern African biodiversityPeople who have contributed content and images.Search Biodiversity Explorer

Carausius morosus (Laboratory or Indian Stick-insect)

Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Ecdysozoa > Panarthropoda > Tritocerebra > Phylum: Arthopoda > Mandibulata > Atelocerata > Panhexapoda > Hexapoda > Insecta (insects) > Dicondyla > Pterygota > Metapterygota > Neoptera > Polyneoptera > Anartioptera > Orthopterida > Phasmida (stick and leaf insects)

Carausius morosus female on ivy Hedera sp.

[photo by P. Brock ]

Description

Male (rare) 48.5-61mm, female 70-84mm. Usually parthenogenetic Parthenogenetic means that adults develop from unfertilised eggs. , stick-like, medium sized wingless insects with medium length antennae. Colour various shades of dull green or brown, sometimes with darker mottling. In adult females the inside base of the forelegs are bright red. The thorax has a number of small tubercles (knobs). The thinner, shorter males are brown. It is believed that those reared in captivity are genetic females with male characteristics, but sterile, which are more frequent when these insects are kept at unusually high temperatures.

Life History and behaviour

Females drop their eggs to the ground. The eggs are round, brown with a yellow knob, which hatch into fragile-looking brown nymphs after about 4-6 months. These moult six times, taking about 4-7 months to mature; adults live 4-6 months, laying several hundred eggs.

When disturbed, nymphs and adults may sway from side to side and may emit a fluid from the mouthparts. They may, however, simply drop to the ground. After all, this is the classic twig mimic, which can remain motionless for hours on end. It has been in culture in Europe since the late 1800s.

Foodplants

In the Cape Town suburbs on ivy Hedera sp. (Araliaceae) and probably many other plants. In captivity will accept numerous plants.

Distribution

A native of India: Palni Hills, Shembagonor and Trichinopoly in Madura province, where this species is believed to reproduce bisexually, at least in part of its range. "Alien" introductions have been reported from the Cape Town area, South Africa, where they are common. Also reported from the UK, Europe and the U.S.A. All the introductions reproduce by parthenogenesis.

Text by Paul Brock

 

Contact us if you can contribute information or images to improve this page.

Biodiversity Explorer home   Iziko home   Search