Eclosion Hormone Activity during the Embryonic Development of the Saturniid Silkmoth, Samia cynthia ricini DONOVAN : Lepidoptera : Saturniidae

1. In pharate Manduca sexta moths eclosion hormone activity was present in the brain and corpora cardiaca. Bursicon activity was confined to the abdominal nervous system, and was most concentrated in the abdominal perivisceral organs (PVOs). 2. When newly emerged moths were given access to suitable wing-spreading sites, bursicon activity was depleted from the PVOs and appeared in the blood within 15 min after eclosion. This hormone was responsible for the tanning and hardening of the wings. 3. Bursicon release could be delayed for at least 24 h by forcing the newly emerged moth to dig. Secretion then occurred swiftly upon giving the moth a suitable wing-spreading site. 4. The pupal cuticle was removed from pharate Manduca approximately 7 h before their normal eclosion gate, and the peeled moths were provided with a wing-spreading site. These moths did not then secrete bursicon until after their normal time of eclosion. 5. Injection of the eclosion hormone into pharate moths caused early eclosion followed by precocious bursicon secretion. 6. It was concluded that bursicon release is regulated by both neural and hormonal factors. The eclosion hormone triggers a program of neural output which includes the secretion of bursicon. This release, however, can be delayed by neural input which is associated with the digging behaviour of the moth.

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Natural and synthetic materials with insect hormone activity

Development ◽

10.1242/dev.20.1.25 ◽

1968 ◽

Vol 20 (1) ◽

pp. 25-31

Author(s):

P. Masner ◽

K. Sláma ◽

V. Landa

Keyword(s):

Embryonic Development ◽

Juvenile Hormone ◽

Abnormal Development ◽

Hormone Activity ◽

Pyrrhocoris Apterus ◽

Synthetic Materials ◽

Juvenile Hormone Analogues ◽

Insect Metamorphosis ◽

Juvenile Hormone Activity ◽

Imaginal Differentiation

The juvenile hormone of insects is known to inhibit the process of insect metamorphosis. It is also known to stimulate ovarian growth in adult females of some species. It has been found recently that some substances with juvenile hormone activity also influence embryonic development. In the bug Pyrrhocoris apterus such substances, which prevent imaginal differentiation in metamorphosis, also affect the differentiation process of embryos at a certain stage of egg development (Sláma & Williams, 1966). This has been confirmed with other juvenile hormone analogues on embryonic development of silkworm eggs (Riddiford & Williams, 1967) and grasshoppers (Novák, 1967). According to the above observations eggs treated with the substances show abnormal development of the embryos, which may pass successfully through the early stages of embryogenesis but are unable to complete differentiation. Usually the embryos do not develop beyond the stage of blastokinesis and die within the egg shells.

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PHYSIOLOGY OF INSECT ECDYSIS

Journal of Experimental Biology ◽

10.1242/jeb.54.3.805 ◽

1971 ◽

Vol 54 (3) ◽

pp. 805-814 ◽

Cited By ~ 1

Author(s):

JAMES W. TRUMAN

Keyword(s):

Behaviour Pattern ◽

Hormone Activity ◽

Eclosion Hormone ◽

Labial Gland Secretion ◽

Five Elements ◽

Species Specific ◽

Surgical Manipulations ◽

The Brain ◽

Behavioural Sequence ◽

Pupal Cuticle

1. In the giant silkmoths, adult eclosion is immediately preceded by a stereotyped series of abdominal movements - the pre-eclosion behaviour. The pattern of movements is species-specific and has a duration of about 1 ¼ h. 2. The pre-eclosion behaviour is followed sequentially by eclosion, the release of the labial gland secretion, the post-eclosion activity, and the spreading of the wings. These five elements of behaviour make up the emergence sequence. 3. The progression from one part of the behavioural sequence to the next is independent of stimuli provided by the pupal cuticle or cocoon, and therefore must be due to an internal programme. Thus, when the pupal cuticle was removed from pharate moths 12 h before their normal eclosion time, these ‘peeled’ animals continued to behave in a pupal fashion. But upon the arrival of the eclosion gate, the entire emergence sequence was displayed. 4. Through surgical manipulations the brain was shown to trigger the pre-eclosion behaviour. Moreover, this action of the brain was mediated by a neurosecretory hormone - the eclosion hormone. 5. Injections of extracts with eclosion-hormone activity triggered the precocious display of the emergence sequence by pharate moths. 6. When the eclosion hormone was injected into the isolated abdomens of pharate moths, these fragments performed the pre-eclosion behaviour and then shed the surrounding piece of pupal cuticle. The information for the pre-eclosion behaviour and for the abdominal movements associated with eclosion must therefore be programmed in the abdominal ganglia. Moreover, after its ‘activation’ the abdomen can switch from one behaviour pattern to the next without influence from the higher centres.

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Eclosion hormone activity in haemolymph of eclosing silkmoth, Bombyx mori

Journal of Insect Physiology ◽

10.1016/0022-1910(84)90027-1 ◽

1984 ◽

Vol 30 (6) ◽

pp. 471-475 ◽

Cited By ~ 4

Author(s):

Hajime Fugo ◽

Yuko Iwata ◽

Makoto Nakajima

Keyword(s):

Bombyx Mori ◽

Hormone Activity ◽

Eclosion Hormone

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BLOCKING OF EMBRYONIC DEVELOPMENT IN THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE), BY SOME COMPOUNDS WITH JUVENILE HORMONE ACTIVITY

The Canadian Entomologist ◽

10.4039/ent1021592-12 ◽

1970 ◽

Vol 102 (12) ◽

pp. 1592-1596 ◽

Cited By ~ 28

Author(s):

Arthur Retnakaran

Keyword(s):

Embryonic Development ◽

Juvenile Hormone ◽

Choristoneura Fumiferana ◽

Spruce Budworm ◽

Dosage Level ◽

Egg Mass ◽

Hormone Activity ◽

Juvenile Hormone Activity ◽

Effect Of Treatment ◽

Embryonic Death

AbstractThe effect of treatment with juvenile hormone and five of its analogs on embryonic development of the spruce budworm was studied. All compounds were applied topically in acetone solution to budworm egg masses, and all were found to have ovicidal activity. Most active was the dichloro analog, which required a minimum dosage of 50 μg per egg mass to ensure embryonic death in all the treated eggs. A similar result was found for juvenile hormone, while juvabione, ethyl-aromatic terpenoid ether, and farnesyl methyl ether required a dosage of 100 μg per egg mass to achieve this result. At this latter dosage level, 6% of the eggs treated with methyl aromatic terpenoid ether hatched.

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Eclosion hormone activity in developing embryos of the silkworm, Bombyx mori

Journal of Insect Physiology ◽

10.1016/0022-1910(85)90005-8 ◽

1985 ◽

Vol 31 (4) ◽

pp. 293-298 ◽

Cited By ~ 15

Author(s):

Hajime Fugo ◽

Hitoshi Saito ◽

Hiromichi Nagasawa ◽

Akinori Suzuki

Keyword(s):

Bombyx Mori ◽

Hormone Activity ◽

Eclosion Hormone ◽

Silkworm Bombyx Mori

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Live Confocal Analysis of Fertilization and Early Development

Microscopy and Microanalysis ◽

10.1017/s1431927600031135 ◽

2001 ◽

Vol 7 (S2) ◽

pp. 1012-1013

Author(s):

Uyen Tram ◽

William Sullivan

Keyword(s):

Drosophila Melanogaster ◽

Embryonic Development ◽

Real Time ◽

Early Development ◽

Fluorescent Probes ◽

Primary Defect ◽

Fluorescent Analysis ◽

Dynamic Event ◽

Enormous Amount ◽

Fluorescent Studies

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.

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