• Studies on the reproductive biology

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/anml/087/09/0229-0247

    • Keywords

       

      Therea petiveriana ; Crepuscular scrub jungle habitats; Coutship; mating; dextral ortheca carrying; senescent females and virgins oviposit single eggs; pleural; pouches with secreting hypodermis; alerting pheromonal action

    • Abstract

       

      Therea petiveriana (L.), the seven white spotted fessorial roach of the scrub jungles of South India is seasonal, univoltine and is very restricted in its distribution. The males emerge earlier than the females, soon after the first rain in summer. The cryptic nymphs are subterranean and the adults are predominantly crepuscular. The males that play the active role in courtship and mating, start the process by the characteristic antennal caressing. Depending on the intensity of receptivity of the relatively passive partner, he spares no time in backing into her genitalia to achieve the end to end position of genital connection. Mated couples go subterranean forthwith. The females choose reasonably wet substratum for resting as well as for ootheca deposition. The ootheca rotation is invariably dextral. Senescent females as well as virgins oviposit single eggs and the number of eggs in each completed ootheca ranges from 12–16. The process of oviposition starts early in the mornings as well as late in the evenings and the oothecae are carried longer when the substratutum remains dry.

      The pairedpleural pouches are elaborate development of the pleuron of the second and third abdominal segments. These pouches are kept withdrawn into the body cavity by a set of retractor muscles that originates at the bottom of the pouch and gets inserted at the antecosta of the corresponding segment. Young adults, when perturbed, instantaneously lift the wings and fling open the tergites and sternites in order to expose the hairy pleats of the fully projected plural pouches. Projection is brought about by the haemocoelic fluid pressure. The well developed hypodermis of the pleural pouches of young adults has an outer tier of cuticle secreting small compactly packed cells and a basal tier of large secretory cells, the secretion of which is considered to function as alerting pheromone.

    • Author Affiliations

       

      D Livingstone1 R Ramani1

      1. Division of Entomology, Department of Zoology, University of Madras, Autonomous PG Centre, Coimbatore - 641 004
    • Dates

       
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