Titres of juvenile hormone I, II and III in Spodoptera littoralis (Noctuidae) from the egg to the pupal moult and their modification by the egg–larval parasitoid Chelonus inanitus (Braconidae)

Steiner, Bernhard; Pfister-Wilhelm, Rita; Grossniklaus-Bürgin, Christa; Rembold, Heinz; Treiblmayr, Karl; Lanzrein, Beatrice

doi:10.1016/s0022-1910(98)00139-5

Cited by 49 publications

(24 citation statements)

References 45 publications

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“…However, the effect of intraspecific differences of different ages of the last stadium of S. littoralis on host acceptance by the parasitoid may return to the host quality in which old hosts (24 h old) were less suitable physiologically for parasitoid development than young hosts (0-3 h old). Zimowska et al (1989) and Steiner et al (1999) reported that the juvenile hormone (JH) in the last instar S. littoralis larvae is almost exclusively limited to JHII with two major peaks: the first at the beginning of the stadium (0 h old) and the second at the end of feeding period (48 h old).…”

Section: Discussionmentioning

confidence: 99%

“…This trend may reflect differences in mortality after parasitization since the "endocrinological suitability" of 5th and 6th host instars likely differs for the parasitoid. Variations in JH quantity and its homologous composition throughout the development of S. littoralis larvae (Grossniklaus-Bürgin et al, 1998;Steiner et al, 1999) may be attributed in part to the partial breakdown of the solitary habit observed in the last two instars of S. littoralis larvae.…”

Section: Discussionmentioning

confidence: 99%

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Developmental interaction between suboptimal instars of Spodoptera littoralis (Lepidoptera:Noctuidae) and its parasitoid Microplitis rufiventris (Hymenoptera:Braconidae)

Hegazi

Khafagi²

2005

Arch Insect Biochem Physiol

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Relative effects of parasitism by Microplitis rufiventris on the development of the third instar Spodoptera littoralis (preferable, optimal host) with the development of penultimate (5th) and last (6th) instars (suboptimal hosts) were investigated. Newly molted 6th instar hosts were more acceptable for parasitization by the wasp female than older hosts. In singly parasitized 3rd instar hosts, 82.0 +/- 3.9% of the parasitoid eggs developed to full-grown instar wasp larvae. However, parasitoid eggs deposited singly in 73.9 +/- 3.3% of 5th and 100% of 6th instar hosts failed to develop. Superparasitization in the 3rd instar hosts reduced the production of pseudoparasitized larvae and, conversely, all parasitized hosts yielded viable parasitoid offspring. In suboptimal hosts, the development interaction between the parasitoid and its host larvae was highly influenced by the age of hosts at parasitism, load of deposited eggs, and other parasitoid factors. The latter factors, e.g., mainly calyx fluid particles, might be involved in establishing parasitoid eggs in the suboptimal hosts. In the last two host instars, superparasitization significantly increased the number of parasitoid larvae successfully reaching their final instar. Variation in host quality, e.g., physiological status, might be attributed, in part, to the partial breakdown of the solitary habit observed in the earlier instars. More parasitoid eggs developed to mature parasitoid larvae in hosts superparasitized as 6th instar than parasitoid eggs laid in 5th instar hosts. Superparasitization significantly lengthened the developmental period of 5th and 6th host instars and inhibited their development to the pupal stage. Studying parasitoid development in suboptimal instars of its habitual host provided physiological insight, as shown here. The results may have implication for biological control and in vitro mass rearing programs with solitary parasitoids.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Developmental interaction between suboptimal instars of Spodoptera littoralis (Lepidoptera:Noctuidae) and its parasitoid Microplitis rufiventris (Hymenoptera:Braconidae)

Hegazi

Khafagi²

2005

Arch Insect Biochem Physiol

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“…Normalized activity was calculated as the amount of firefly luciferase activity divided by the activity reported by a cotransfected plasmid constitutively expressing Renilla luciferase, as per manufacturer protocol (Promega). Between 24 and 48 h after the transfection, the cells were treated with 1 μM 20-OH ecdysone (“20E), or with 100 μM juvenile hormone III (“JH III”, a naturally occurring form of JH in Noctuidae; Steinera et al, 1999), or with both hormones (both obtained from Sigma-Aldrich), or with just EtOH carrier only (final EtOH concentration 1–2%). At the indicated hours after hormone treatment, the cells were harvested and the reported activity measured.…”

Section: Methodsmentioning

confidence: 99%

Juvenile hormone action through a defined enhancer motif to modulate ecdysteroid-activation of natural core promoters

Jones

Fang

et al. 2012

Comparative Biochemistry and Physiology Part B: Biochemistry an

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We have established a model system of hormone action, in an Sf9 cell transfection system, using defined enhancer motifs and natural core promoters of metamorphosis-associated genes. The DR1 enhancer, that is an established DNA binding site for the ecdysone receptor/ultraspiracle heterodimer, was necessary for transcriptional activation by 20-OH ecdysone. For this activated transcription, a natural sequence closely 5′ to the TATA box is necessary. Cotreatment with juvenile hormone III strongly suppressed the steroid activation of transcription. However, in the absence of the sequence located closely 5′ to the TATA box, cotreatment with juvenile hormone instead increased transcription over that occurring due to 20-hydroxy-ecdysone alone. This sensitivity to activation by cotreatment with juvenile hormone could be transferred to a related, but otherwise unresponsive, hexamerin core promoter simply by transferring to the unresponsive promoter the five base transcription start site (ACAGT) from the responsive hexamerin gene. These are the first reports that the direction of JH action on 20-OH ecdysone-activated transcription can be reversed by removal of a sequence at the core promoter, and that modulatory action of juvenile hormone can be transferred to a different gene by transferring the transcription start site motif.

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“…Also, JHII was much less effective in disrupting the egg and larval stages of the parasitoid than JHI. It is reported by Steiner et al (1999) that in S. littoralis larvae only JHII and JHIII were found. The possible changes in parasitoid biology caused by JHs could seriously limit the role of the parasitoids in the natural regulation of insect pests.…”

Section: Resultsmentioning

confidence: 92%

Developmental status of endo-developmental stages ofMicroplitis rufiventriskok. inSpodoptera littoralis(boisd.) larvae topically treated by juvenile hormones I and II

Khafagi¹

2003

Archives Of Phytopathology And Plant Protection

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The juvenile hormones I and II (JHI and JHII) were topically applied at concentrations of 1 or 5 mg to Spodoptera littoralis larvae containing newly deposited eggs of Microplitis rufiventris. The study demonstrated that both hormones do influence several aspects of the development of the parasitoid after treatment of its host larvae. Of these effects: (1) significant lengthening of periods of eggs and larvae, (2) moulting failure of parasitic larvae, (3) moulting the parasitic larvae into supernumerary instar, (4) arrest of postembryonic development in the first larval instar, (5) reduction in the emergence rate of parasitoid larvae, and (6) influence on embryogenesis. The application of JHI was more effective in disrupting the endo-development of the parasitoid than JHII. In all tests, control hosts produced significantly (P 5 0.01) more parasitoids than treated ones. Off-target effects on natural enemies may seriously limit the use of JHs, especially in integrated control programmes.

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Titres of juvenile hormone I, II and III in Spodoptera littoralis (Noctuidae) from the egg to the pupal moult and their modification by the egg–larval parasitoid Chelonus inanitus (Braconidae)

Cited by 49 publications

References 45 publications

Developmental interaction between suboptimal instars of Spodoptera littoralis (Lepidoptera:Noctuidae) and its parasitoid Microplitis rufiventris (Hymenoptera:Braconidae)

Developmental interaction between suboptimal instars of Spodoptera littoralis (Lepidoptera:Noctuidae) and its parasitoid Microplitis rufiventris (Hymenoptera:Braconidae)

Juvenile hormone action through a defined enhancer motif to modulate ecdysteroid-activation of natural core promoters

Developmental status of endo-developmental stages ofMicroplitis rufiventriskok. inSpodoptera littoralis(boisd.) larvae topically treated by juvenile hormones I and II

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