by Dr.Avantika bhaskar
Cockroaches are highly diverse with nearly 4000 described species. Therea petiveriana (Linnaeus, 1758) is also known as ‘desert cockroach’, ‘seven-spotted cockroach’ or ‘Indian domino cockroach’. It belongs to a primitive family of cockroaches (Blaberoidea: Polyphagidae). It inhabits waste heaps in and around human habitations as well as humus accumulations in the scrub jungles of south India.
Their appearance with white spots on a black base is believed to mimic the aggressive ground beetle, Anthia sexguttata which displays strong defense mechanism with the ability to spray irritants. The upper-side of their abdomen is orange-yellow hidden by tegmina (leathery forewing of an insect). The head is bent back underneath the pronotal (the dorsal sclerite of the prothorax) shield with ocelli (a simple eye) facing forward. Ocelli play a significant role in photoreception during activity. Both adult males and females are flightless despite having large wings. Like other cockroaches they use pheromones to communicate and the defensive secretions of the glandular pouches of the adults act as an alarm pheromone.
The species is quite gregarious, essentially crepuscular and remains subterranean during periods of non-activity. The males emerge earlier than females, soon after the first rain in summer. After mating the female deposits ootheca (egg mass) on a wet substratum containing 12-16 eggs. Up to 13 oothecae are laid by a female over 3 to 40 days.
The domino roach is quite popular as a pet because of its hardiness and easy maintenance.
- Farine, J. P., Semon, E., Everaerts, C., Abed, D., Grandcolas, P. and Brossut, R. (2002). Defensive secretion of Therea petiveriana: chemical identification and evidence of an alarm function. Chem. Ecol. 28(8): 1629–1640. doi:10.1023/A:1019932630787.
- Grandcolas, Ph. (1998). Domestic and non-domestic cockroaches: facts versus received ideas. Rev.fr.Allergol., 38 (10): 833-838.
- Livingston, D. and Rajambal, M. (1980). Association of ocelli with the neuroendocrine system of Therea petiveriana (L.) (Blaberoidea: Polyphagidae). Indian Acad. Sci. (Anim. Sci.), 89(2): 147–153. doi:10.1007/BF03179155.
- Livingstone, D and Ramani, R (1978). Studies on the reproductive biology. Indian Acad. Sci. 87: 229–247.
- The Global Biodiversity Information Facility: GBIF Backbone Taxonomy, 2013-07-01. Accessed via http://www.gbif.org/species/5151691 on 2015-03-10.