Carausius morosus

Brunner von Wattenwyl, 1907

Indian Walking Stick, Common Stick Insect, Laboratory Stick Insect

Carausius morosus is a parthenogenetic phasmid native to Tamil Nadu, India, widely distributed globally through accidental introductions and captive culture. Females reproduce without males; no wild males have been reported, though gynandromorphs occasionally occur in captivity. The is , feeding at night and remaining motionless during daylight hours. It has become established outside its native range in locations including Great Britain, Portugal, South Africa, and the United States, where it occasionally damages ornamental plants.

Pronunciation

How to pronounce Carausius morosus: //kæˈraʊ.zi.əs moʊˈrəʊ.səs//

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Identification

Females are slender and twig-like, 80–100 mm in length, ranging from light green to dark brown. Red patches occur at the base of the forelegs; yellow patches occur at the base of the mid-legs. are 2 mm, ovoid, brown, with a beige capitulum at one end. Males are unknown; all established consist of females. Gynandromorphs with mixed sexual characteristics have been documented in laboratory culture but not in wild populations.

Habitat

Native to tropical and subtropical regions of southern India. Introduced inhabit gardens, greenhouses, and urban environments with suitable plants. Laboratory cultures are maintained at 23°C, 70% relative humidity, and 12:12 light-dark cycles.

Distribution

to Tamil Nadu, India. Established introduced recorded in Great Britain, Portugal, South Africa, and the United States (including California). GBIF records document occurrence on several Azorean islands (Faial, Pico, São Miguel, Santa Maria, Terceira).

Seasonality

activity pattern; feeds at night, rests motionless during daylight.

Diet

Foliivorous; feeds on leaves of various plants. Specific plant preferences documented in introduced include numerous ornamental plant .

Life Cycle

are haploid, 2 mm in length, ovoid and brown with a beige capitulum. Upon hatching, the capitulum plug opens and dark, thread-like nymphs emerge. Laboratory colonies have been maintained for over two years under standardized conditions; specific developmental durations and lifespan not documented in available sources.

Behavior

Primary defense is (feigning death): when disturbed, the body becomes rigid with legs held along the body axis. Swaying mimics wind-blown foliage. feeding activity; resting posture typically has legs aligned with the body axis. Two types of periodic tarsal movements occur at rest: 'wagging' (faint, 80–120 per minute in undisturbed animals) and 'waving' (stronger, 8–22 per minute, more common after transection). Waving can be suppressed by abdominal stimuli and probably ceases during .

Human Relevance

Widely used as a laboratory model organism for developmental, behavioral, and physiological research. Commonly kept as a pet and educational specimen in schools. Accidental introductions have caused minor economic damage to ornamental horticulture in some regions.

Similar Taxa

Other Carausius speciesC. morosus is distinguished by its parthenogenetic , lack of males, and specific leg coloration (red foreleg bases, yellow mid-leg bases).
Other Lonchodidae phasmidsCombination of small size (80–100 mm), slender twig-like form, specific leg markings, and known parthenogenetic laboratory distinguishes C. morosus from congeneric and confamilial .