open access

https://hdl.handle.net/2115/44895

Juvenile Hormone titre and vitellogenin gene expression related to ovarian development in primary reproductives compared with nymphs and nymphoid reproductives of the termite Reticulitermes speratus

英語

vitellogenin

2010-03

Blackwell Publishing

Physiological Entomology

35(1)

52-58

To elucidate the reproductive cycle of termite queens, incipient colonies of Reticulitemes speratus (Isoptera: Rhinotermitidae) were established under laboratory conditions, and the transition of colony development was observed at 0.5, 1.5, 2.5, 3.5, and 7.5 months (stages I-V, respectively) after colony foundation. Ovarian development, vitellogenin gene expression, and Juvenile Hormone (JH) titres are examined in the queens and in non-physogastric nymphoids collected from natural colonies. A reproductive cycle in queens is observed, in which the oviposition rate is relatively higher during stages I and II, and then decreases during stages III and IV. Vitellogenic oocytes are not observed in the ovary during stages III and IV, and the expression level of the vitellogenin gene is low, suggesting that egg production in queens is repressed during these stages. However, vitellogen gene expression and egg deposition in queens resumes during stage V. Juvenile Hormone levels rise during the transition from nymphs to stage-I queens, and elevated JH titres are observed also during stages III and IV. The decrease in JH titre in queens at stage II precedes the decline in vitellogenesis at stages III and IV. Thus, JH titre and vitellogenesis are correlated in an offset pattern. However, non-physogastric nymphoid reproductives do not have vitellogenic oocytes in their ovaries, and their JH titre is two-fold higher than that of queens, suggesting that elevated JH titre precedes vitellogenesis as in queens.

学術雑誌論文

Accepted Manuscript

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