Shuji Itakura, Satoshi Kawabata, Hiromi Tanaka, Akio Enoki
Journal of Insect Science 8 (13), 1-11, (1 February 2008) https://doi.org/10.1673/031.008.1301
KEYWORDS: caste differentiation, ergatoids, juvenile hormone metabolism, Coptotermes formosanus
The aromatic β-carboline norharmane was determined in workers, nymphs, and ergatoids of Reticulitermes speratus (Kolbe) (Isoptera: Rhinotermitidae) by gas chromatography/mass spectrometry. Norharmane levels in workers, nymphs, and ergatoids collected in May (∼4.3 ng/termite) were higher than those in November (∼0.2 ng/termite). Fluorescence of norharmane was observed in histological sections in whole animals and in the fat body. Norharmane, at a final concentration of 1 mM, stimulated juvenile hormone epoxide hydrolase (JHEH) activity of enzyme extract from ergatoids, but inhibited JHEH activity at higher concentrations. The elevated JHEH activity stimulated by norharmane should accelerate juvenile hormone metabolism in R. speratus.