Possible Function of Norharmane in Egg-Laying by Ergatoids and Nymphoids of the Lower Termite, Reticulitermes speratus (Kolbe)

Abstract

The aromatic  -carboline norharmane, which is located in the fat body of Reticulitermes speratus, stimulated the activity of juvenile hormone epoxide hydrolase (JHEH) of larva, ergatoid, and nymphoid homogenates. JHEH activity of ergatoid (16.67 ± 1.30 μU/termite) and nymphoid (20.94 ± 1.64 μU/termite) homogenates fortified with 0.1 mM norharmane was significantly higher than that of ergatoid (9.84 ± 1.69 μU/termite) and nymphoid (16.99 ± 0.60 μU/termite) homogenates to which no norharmane was added. Egg-laying by ergatoids and nymphoids, which ingested norharmane by feeding on norharmane-treated filter paper, was observed in 3 weeks. During rearing on filter paper with- out norharmane, egg-laying by ergatoids was observed in 5 weeks, whereas no egg-laying by nymphoids was observed throughout the incubation period of 8 weeks. Norharmane seems to be involved in egg development of ergatoids and nymphoids of R. speratus.