scholarly journals Alternative Use of the Insecticide Diofenolan on Musca domestica (Diptera: Muscidae): A Morphological and Ultrastructural Investigation

2021 ◽  
Vol 13 (18) ◽  
pp. 10122
Author(s):  
Marco Pezzi ◽  
Chiara Scapoli ◽  
Maria Gabriella Marchetti ◽  
Milvia Chicca ◽  
Stjepan Krčmar ◽  
...  
Keyword(s):  
Juvenile Hormone ◽  
Musca Domestica ◽  
Ultrastructural Level ◽  
Egg Laying ◽  
Corpora Allata ◽  
Endocrine Gland ◽  
Insect Growth Regulators ◽  
Morphological Alterations ◽  
Larval Stages ◽  
Reproductive Ability

Musca domestica Linnaeus (Diptera: Muscidae), a relevant synanthropic pest, is the most frequent dipteran species in farms and waste landfills. Insect Growth Regulators (IGR), insecticides with species-specific toxicity and low health and environmental impact, are known to act mostly on larval stages but may induce sterility in adults. We investigated the effects of diofenolan, an IGR analogue of juvenile hormone, on M. domestica, with special attention to female reproductive ability (egg-laying and hatching), and ovarian and ovariole morphology, using optical and transmission electron microscopy. We also tested the interactions between diofenolan and the activity of corpora allata, endocrine gland producing juvenile hormone required for ovarian development, by morphological and ultrastructural investigations. The results show that diofenolan negatively affects the reproductive ability of M. domestica, causing extensive morphological alterations in ovaries and ovarioles. In treated females, ovarioles showed nine different morphotypes that could be arranged into three “transformation paths”, and these alterations were able to reduce egg-laying. The effects of diofenolan on corpora allata, investigated at the optical and ultrastructural level in M. domestica, showed extensive alterations of the nuclei, cytoplasms, and mitochondria, strongly suggesting a rapid transition of the gland from inactivity to degeneration. The sterilizing effects of diofenolan in M. domestica are very interesting for integrated pest management programs within sustainable defence strategies against this relevant and annoying pest.

The Hormonal Control of the Development of Hairs and Bristles in the Milkweed Bug, ONCOPELTUS FASCIATUS, DALL

1966 ◽  
Vol 44 (3) ◽  
pp. 507-522
Author(s):  
PETER A. LAWRENCE
Keyword(s):  
Juvenile Hormone ◽  
Mode Of Action ◽  
Hormonal Control ◽  
Oncopeltus Fasciatus ◽  
Corpora Allata ◽  
Moult Cycle ◽  
Dense Population ◽  
Milkweed Bug ◽  
Larval Stages ◽  
Hormonal Milieu

1. As in Rhodnius, the larval Oncopeltus has bristles which are supplemented at each moult. However, at metamorphosis a dense population of non-innervated hairs develops. 2. Implantation of corpora allata into 5th-stage larvae showed that the development of these hairs can be inhibited universally or locally by the juvenile hormone (JH). 3. Transplantations of integument between 5th-stage larvae of different stages in the moult cycle gave some information about the power of the host to synchronize the graft to its own moult cycle. 4. Transplantations between different larval stages showed that the grafted in tegument responded to the hormonal milieu of the host. 5. Adult integument was transplanted onto larvae to study the reversal of metamorphosis. It was found that the development of a supernumerary population of hairs depended on the integument passing through a moult cycle in the presence of JH. After two moults in the presence of JH, reversal of metamorphosis was found to vary over the surface of the transplant, being further advanced at the margin. At the edge of the graft properly formed larval bristles developed, while at the centre adult hairs were formed in adult cuticle. Intermediately formed bristles were found in the intervening areas. It is suggested that reactions associated with wounding are the cause of this heterogeneous result. 6. The significance of these results in relation to other work and to theories concerning the mode of action of the juvenile hormone is discussed.

scholarly journals Intercellular Communication in an Insect Endocrine Gland

1986 ◽  
Vol 121 (1) ◽  
pp. 407-419
Author(s):  
D. J. LOCOCO ◽  
C. S. THOMPSON ◽  
S. S. TOBE
Keyword(s):  
Juvenile Hormone ◽  
Plasma Membranes ◽  
Lucifer Yellow ◽  
Ionic Current ◽  
Current Injection ◽  
Corpora Allata ◽  
Intracellular Camp ◽  
Endocrine Gland ◽  
Length Constant ◽  
Electrotonic Potential

1. The parenchymal cells of the corpora allata (CA) of the cockroach Diploptera punctata are coupled through low-resistance intercellular pathways. 2. Extensive dye coupling of cells of CA from fourth instar and adult female cockroaches was revealed following iontophoretic injection of Lucifer Yellow. 3. Freeze-etch electron microscopy revealed numerous gap-junction-like particles in CA cell plasma membranes. 4. The spread of ionic current from cell to cell was demonstrated by injecting current pulses into one cell and recording electrotonic potentials from other cells. The amplitude of electrotonic potentials elicited by negative current injection varied inversely with the rate of juvenile hormone biosynthesis by the CA. 5. The ‘length constant‘ (distance at which an electrotonic potential in CA cells decays to 37% of its magnitude at the site of current injection) could not be measured accurately, but was found to be much greater than the length of the CA. 6. Forskolin- and IBMX-induced elevation of intracellular cAMP increased the electrotonic potential but reduced juvenile hormone release of day 8 CA.

scholarly journals Development and silk production by silkworm larvae after topical application of methoprene

2002 ◽  
Vol 59 (3) ◽  
pp. 585-588 ◽  
Author(s):  
José Ednilson Miranda ◽  
Sérgio Antonio de Bortoli ◽  
Roque Takahashi
Keyword(s):  
Juvenile Hormone ◽  
Larval Instar ◽  
Negative Effects ◽  
Hormone Analogue ◽  
Insect Growth Regulators ◽  
Silkworm Larvae ◽  
Silk Production ◽  
Juvenile Hormone Analogues ◽  
Chemical Products ◽  
Silkworm Bombyx Mori

Juvenile hormone analogues have been tested as insect growth regulators in silkworm (Bombyx mori), seeking an increment of silk production. These chemical products, when applied in small or moderate rates, promote the extension of the last larval instar. To understand the physiologic consequences on silk production by the silkworm strain C115 x N108, the application of methoprene, a juvenile hormone analogue, was performed to evaluate its effects on larval development and silk production. Methoprene was topically applied 48h after the fourth larval ecdysis, on the dorsal integument of the 2nd thoracic segment of the insects, at seven rates between 0 and 20 ng a.i. Methoprene influenced positively the duration of the fifth instar and the weight gain of the insects. The application of 1ng methoprene resulted in the heaviest silkglands, cocoons, shell cocoons and pupae weights. Comparatively to the control, the increment on silk production (approximately 24%) by the use of 1ng methoprene was more accentuated than the corresponding negative effects on the cocooning rate (approximately 12%).

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