''Carausius morosus'' (the 'common', 'Indian' or 'laboratory'

stick insect The Phasmatodea (also known as Phasmida or Phasmatoptera) are an order of insects whose members are variously known as stick insects, stick bugs, walkingsticks, stick animals, or bug sticks. They are also occasionally referred to as Devil's da ...

) is a species of

Phasmatodea The Phasmatodea (also known as Phasmida or Phasmatoptera) are an Order (biology), order of insects whose members are variously known as stick insects, stick bugs, walkingsticks, stick animals, or bug sticks. They are also occasionally referred ...

(phasmid) often kept as pets by schools and individuals. Culture stocks originate from a collection from

Tamil Nadu Tamil Nadu (; , TN) is the southernmost States and union territories of India, state of India. The List of states and union territories of India by area, tenth largest Indian state by area and the List of states and union territories of Indi ...

, India. Like the majority of the Phasmatodea, ''C. morosus'' are

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

. Culture stocks are

parthenogenetic Parthenogenesis (; from the Greek + ) is a natural form of asexual reproduction in which the embryo develops directly from an egg without need for fertilization. In animals, parthenogenesis means the development of an embryo from an unfertiliz ...

females that can reproduce without mating. There are no reports of males, although in captivity,

gynandromorph Gynandromorphism is the phenomenon that occurs when an individual organism possesses both male and female phenotypes due to genetic chimera of sex chromosomes in cells across the body and is most easily recognized in species that display sexu ...

s (individuals with both female and male characteristics) are sometimes reared.

Description

Females are elongated and about in length, ranging from a light green to a darkish brown in colour. The front legs have red patches at the base of the forelegs, and similar but yellow patches on the mid-legs. Eggs are in length,

ovoid An oval () is a closed curve in a plane which resembles the outline of an egg. The term is not very specific, but in some areas of mathematics (projective geometry, technical drawing, etc.), it is given a more precise definition, which may inc ...

and brown, with a beige capitula at one end. When the eggs hatch, the plug opens and dark, tiny, string-like young crawl out of the opening. The eggs are

haploid Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Here ''sets of chromosomes'' refers to the num ...

Behaviour

When disturbed, the major defence method is

feigning death Apparent death is a behavior in which animals take on the appearance of being dead. It is an immobile state most often triggered by a predatory attack and can be found in a wide range of animals from insects and crustaceans to mammals, birds, r ...

, the body becoming rigid, and the legs held along the line of the body. They may also be found swaying to mimic the movement of foliage in wind. The insects feed at night, when they are active. During the day, they rest, often with legs in line with the body, on their food plants.

Accidental introductions

Due to their inconspicuous nature, accidental introductions of ''C. morosus'' have been recorded around the world, including

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and the United States, where in some cases they have become a pest. Studies at the

San Diego Zoo The San Diego Zoo is a zoo in San Diego, California, United States, located in Balboa Park (San Diego), Balboa Park. It began with a collection of animals left over from the 1915 Panama–California Exposition that were brought together by its ...

found the introduced species on a large number of ornamental plants.

References

{{DEFAULTSORT:Carausius morosus Lonchodidae Insects described in 1901 Insect rearing