Relationship between an increase of juvenile hormone titer in early instars and the induction of diapause in fully grown larvae of Sesamia nonagrioides

Eizaguirre, Matilde; Schafellner, Christa; López, Carmen; Sehnal, F.

doi:10.1016/j.jinsphys.2005.05.010

Cited by 41 publications

(20 citation statements)

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“…At low winter temperatures in the field, they probably ecdyse in very long intervals and pupate after 1-3 supernumerary larval molts (Fantinou et al, 1998) but in the laboratory they molt more than ten times before they Archives of Insect Biochemistry and Physiology June 2007 doi: 10.1002/arch. either pupate or perish (Eizaguirre et al, 2005). Under our LD conditions the rates of pupation/ death were 9/0, 13/9, 0/4, 4/13, 9/39, and 0/9% in the 9th, 10th, 11th, 12th, 13th, and 14th larval instars, respectively (n=23).…”

Section: Introductionmentioning

confidence: 74%

“…The suppression of metamorphosis in the diapausing larvae is caused by elevated juvenile hormone (JH) titer (Eizaguirre et al, 2005) but nothing is known about the regulation of the instar length. LD larvae of the 4th and 5th instars contain in the hemolymph 20-30 nM JH, while in the SD larvae the titer surpasses 50 nM; either instar is 4-5 days long in both groups of larvae.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

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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“…During the sixth larval instar, differences in hormone levels, proteins and enzymes cause diapausing S. nonagrioides larvae to have extra larval molts while non-diapausing larvae display metamorphosis, molting to pupae [10,23]. Hemolymph bathes the interior larval body and plays an extremely important role in the transport and storage of nutrients [24].…”

Section: Discussionmentioning

confidence: 99%

“…JHBP levels change significantly and are largely regulated by JH itself [31]. The levels of JH are higher in diapausing than in non-diapausing S. nonagrioides sixth-instar larvae [10-12], so the JHBP protein might play an important role during diapause by binding and transporting JH within the hemolymph, avoiding its degradation by unspecific esterase or hydrolase. Other proteins that could be involved in diapause are the serine proteinase inhibitors (serpin), irreversible inhibitors of serine proteases that regulate proteolytic activities in both physiological and pathological situations [32].…”

Section: Discussionmentioning

confidence: 99%

Comparative analysis of hemolymph proteome maps in diapausing and non-diapausing larvae of Sesamia nonagrioides

2012

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BackgroundSesamia nonagrioides is a noctuid that feeds on maize, sugar cane and sorghum in North Africa and Southern Europe. Larvae reared under long day conditions pupate after 5 or 6 larval instars, whereas larvae reared under short day conditions enter diapause and undergo up to 12 molts before dying or pupating. To better understand the mechanism of larval development and diapause, we identified proteins with different expressions in the sixth instar of diapausing and non-diapausing larvae.ResultsA total of 52 differentially regulated proteins were detected in the hemolymph of the diapausing or non-diapausing larvae at the beginning or end of the sixth instar. From these proteins, 11 were identified by mass spectrometry (MALDI-TOF MS or MALDI-TOF/TOF MS/MS): 5 were upregulated in the hemolymph of non-diapausing larvae and 6 in the hemolymph of the diapausing larvae. Interestingly, some proteins were expressed only in non-diapausing larvae but none was expressed only in the hemolymph of diapausing larvae. The possible functions of some of these proteins related to diapause maintenance or to larval-pupal metamorphosis are discussed.ConclusionsThe 2-DE proteomic map of S. nonagrioides hemolymph shows differential protein expression in diapausing and non-diapausing larvae. Some proteins that showed higher expression in the diapausing larvae at the end of the sixth instar could be involved in JH level maintenance thus in the diapause status maintenance. On the contrary, other proteins that showed the highest expression or that were expressed only in the non-diapausing larvae could be involved in larval-pupal metamorphosis.

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“…Ecdysteroids trigger larval-larval and pupal-adult molts when juvenile hormone (JH) titer is low; as long as there is enough JH, ecdysteroids promote larvallarval transition (Yanagi et al 2006). The pupal commitment of S. nonagrioides occurs in the 6 th larval instar in response to the gradual increase of the ecdysteroid titer in the presence of a small amount of juvenile hormone (JH) (Eizaguirre et al 2005). Pupal weights may have increased in corn stalk borer exposed to high concentrations of BPA because of the decreased JH concentration, prior to larval-pupal metamorphosis.…”

Section: Discussionmentioning

confidence: 99%

The physiological impact of bisphenol A on the developmental and reproductive processes ofSesamia nonagrioides(Lepidoptera: Noctuidae) under LD and SD photoperiods

Kontogiannatos

Zakasis

Kourti

2015

Toxicological & Environmental Chemistry

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In this study we examined the physiological impact of Bisphenol A on the developmental and reproductive processes of Sesamia nonagrioides (Lepidoptera: Noctuidae) under 16L:8D (long day, LD) and 10L:14D (short day, SD) photoperiods. Larvae were continuously exposed to different concentrations of BPA (1, 10 and 100 μg/L) applied in their artificial diets, under LD and SD conditions. During LD photoperiod increased pupal weights were observed in insects grown in culture media with the higher dose of 100 μg/L BPA. The morphological effects of BPA on the reproductive system of S. nonagrioides were also evaluated. Testis size was significantly decreased, while ovaries' size was increased in BPA-treated animals. The sex ratio shifted in favor of females when the larvae were exposed to BPA. During SD photoperiod the BPA exposure significantly decreased larval weight. Additionally, semi-quantitative RT-PCR analyses were used to identify the effects of BPA in the transcriptional regulation of heat shock protein genes SnoHsp20.8, SnoHsc70 and SnoHsp83 during SD conditions. During diapause Downloaded by [University of Otago] at 13:19 15 July 2015 A c c e p t e d M a n u s c r i p t 2 conditions, the expression levels of SnoHsp20.8 and SnoHsp83 were not affected by BPA, while SnoHsc70 mRNA levels were decreased.Here we observed a differential impact of BPA during non-diapausing and diapausing conditions. Our results revealed the physiological impact of environmentally relevant concentrations of BPA in S. nonagrioides.

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Relationship between an increase of juvenile hormone titer in early instars and the induction of diapause in fully grown larvae of Sesamia nonagrioides

Cited by 41 publications

References 24 publications

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

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

Comparative analysis of hemolymph proteome maps in diapausing and non-diapausing larvae of Sesamia nonagrioides

The physiological impact of bisphenol A on the developmental and reproductive processes ofSesamia nonagrioides(Lepidoptera: Noctuidae) under LD and SD photoperiods

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