Juvenile hormone-mediated termination of larval diapause in the bamboo borer, Omphisa fuscidentalis

Singtripop, Tippawan; Wanichacheewa, Somsak; Sakurai, Shunsuke

doi:10.1016/s0965-1748(00)00057-6

Cited by 59 publications

(48 citation statements)

References 25 publications

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“…The 20E (Sigma, St. Louis, MO, USA) was dissolved in distilled water at a concentration of 1 mg/ml and stored at À20 1C until use. The stock solution was diluted with distilled water, and larvae were injected with 5-ml aliquots through the first proleg (Singtripop et al, 2000).…”

Section: Hormonesmentioning

confidence: 99%

Regulation of soluble and membrane-bound trehalase activity and expression of the enzyme in the larval midgut of the bamboo borer Omphisa fuscidentalis

Tatun

Singtripop

Tungjitwitayakul

et al. 2008

Insect Biochemistry and Molecular Biology

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Section: Hormonesmentioning

confidence: 99%

Regulation of soluble and membrane-bound trehalase activity and expression of the enzyme in the larval midgut of the bamboo borer Omphisa fuscidentalis

Tatun

Singtripop

Tungjitwitayakul

et al. 2008

Insect Biochemistry and Molecular Biology

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“…Prothoracic glands of diapause larvae produce minute but significant amount of ecdysone (Singtripop et al ., 2000), and hemolymph ecdysteroid concentration is at a 10 -8 M level (0.01-0.03 µ g/ml) during mid-to late diapause (Singtripop et al ., 2002). Nevertheless the diapause is not terminated in January, indicating that the concentration is not enough for the positive feedback activation of prothoracic gland.…”

Section: Discussionmentioning

confidence: 99%

“…Fifteen larvae were used in each month and were observed daily for 6 weeks after the injections unless mentioned otherwise. We recorded the percentage of pupated animals that was referred to as responsiveness of larvae to 20E, and the duration from the day of 20E treatment to the day of the formation of pupal cuticle of Grade 2 (Singtripop et al, 2000), that was defined as sensitivity of larvae to 20E.…”

Section: Hormonesmentioning

confidence: 99%

“…Induction of pupation by 20E in the diapause larvae of Omphisa fuscidentalis in January 1998. Percent pupation (responsiveness), which is the percentage of larvae producing pupal cuticle (Grade 2; Singtripop et al ., 2000), is shown as a function of 20E doses. Fifteen larvae were used for each dose.…”

Section: Monthly Changes In Responsiveness To 20ementioning

confidence: 99%

“…In addition, topically applied juvenile hormone analogue (JHA) breaks the diapause through an activation of prothoracic gland (Singtripop et al ., 2000). These indicated that 20E injection might yield a single type of larval response, pupation, and therefore this species appeared suitable to examine the progress of diapause using the sensitivity to 20E.…”

Section: Introductionmentioning

confidence: 99%

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Intensity of Larval Diapause in the Bamboo Borer, Omphisa fuscidentalis

2002

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-Larvae of the bamboo borer, Omphisa fuscidentalis , enter larval diapause in September and pupate in the following June (Singtripop et al ., 1999). We examined the changes in the responses of larvae to exogenous 20-hydroxyecdysone (20E) in order to estimate the progress of diapause development. In this respect, we adopted two terms, responsiveness and sensitivity of larvae to 20E. Responsiveness was estimated by the percentage of larvae that pupated, and sensitivity was evaluated by the duration from the day of 20E injection to pupation. The responsiveness of larvae declined gradually from September to November when larvae were least responsive to 20E, and then increased markedly from January to February. This indicates that the intensity of diapause increases from September to November and terminated gradually thereafter. Thus the sequence of events as the larval responses to 20E is characterized by a V-shaped curve. Sensitivity of larvae to 20E was at the same level from September to December, and increased remarkably from December to January. The abrupt increase in the sensitivity occurred one month earlier than the bottom of the V-shaped curve of larval responsiveness, suggesting that the increases in the responsiveness and sensitivity in the latter half of diapause may be brought about by respective mechanisms.

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Effects of ecdysteroid agonist RH‐2485 reveal interactions between ecdysteroids and juvenile hormones in the development of Sesamia nonagrioides

Eizaguirre

López

Schafellner

et al. 2007

Arch Insect Biochem Physiol

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Larvae of Sesamia nonagrioides developing under long day (LD) conditions pupate in the 5th or 6th instar, whereas under the short day (SD) conditions, they undergo several supernumerary larval molts and are regarded as diapausing. The development in early larval instars occurs in the LD larvae at a moderate and in the SD larvae at a high juvenile hormone (JH) titer; ecdysteroid titer cycles similarly under both conditions. The transformation to pupa is initiated by a burst of ecdysteroids at undetectable JH levels, whereas extra larval molts in the diapausing larvae are associated with moderate JH titer and irregular rises of ecdysteroids. Application of 0.2 ppm RH-2485 to the diet of the 6th instar larvae promotes hormonal changes supporting metamorphosis in the LD larvae and slightly accelerates larval molts in the diapausing SD larvae. The 0.5- and 1-ppm doses revert these patterns of endocrine regulations to a mode typical for early larval instars. Particularly dramatic is a JH titer increase provoked within 24 h in the LD larvae. After the treatment, both the LD and SD larvae undergo a series of larval molts, suggesting that hormonal programming of the larval development has been stabilized. A few insects receiving 1 ppm RH-2485, and a high proportion of those fed with 5 ppm RH-2485, deposit two cuticles within a single apolysis and die.

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Juvenile hormone-mediated termination of larval diapause in the bamboo borer, Omphisa fuscidentalis

Cited by 59 publications

References 25 publications

Regulation of soluble and membrane-bound trehalase activity and expression of the enzyme in the larval midgut of the bamboo borer Omphisa fuscidentalis

Regulation of soluble and membrane-bound trehalase activity and expression of the enzyme in the larval midgut of the bamboo borer Omphisa fuscidentalis

Intensity of Larval Diapause in the Bamboo Borer, Omphisa fuscidentalis

Effects of ecdysteroid agonist RH‐2485 reveal interactions between ecdysteroids and juvenile hormones in the development of Sesamia nonagrioides

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