HORMONAL INDUCTION OF SUPERNUMERARY INSTARS IN THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1973 ◽  
Vol 105 (3) ◽  
pp. 459-461 ◽  
Author(s):  
Arthur Retnakaran
Keyword(s):  
Juvenile Hormone ◽  
Choristoneura Fumiferana ◽  
Larval Instar ◽  
Spruce Budworm ◽  
Hormone Analogue ◽  
Larval Instars ◽  
Juvenile Hormone Analogue ◽  
Hormonal Induction

AbstractInduction of supernumerary larval instars in the spruce budworm, Choristoneura fumiferana Clemens, by applying ZR-515, a potent juvenile hormone analogue, is explained in terms of larval differentiation. Application to the early sixth instar where structures are relatively indeterminate results in the formation of a supernumerary larval instar, whereas treatment of the late-larva wherein many structures are committed to differentiate towards the pupa, results in a larval–pupal mosaic.

EFFECT OF BODY WEIGHT ON LETHAL EFFECTIVENESS OF A JUVENILE HORMONE ANALOGUE APPLIED TO MALE AND FEMALE WESTERN SPRUCE BUDWORM (CHORISTONEURA OCCIDENTALS) (LEPIDOPTERA: TORTRICIDAE)

1982 ◽  
Vol 114 (11) ◽  
pp. 1063-1068 ◽  
Author(s):  
Jacqueline L. Robertson
Keyword(s):  
Body Weight ◽  
Juvenile Hormone ◽  
Spruce Budworm ◽  
Ethyl Carbamate ◽  
Choristoneura Occidentalis ◽  
Western Spruce Budworm ◽  
Hormone Analogue ◽  
Juvenile Hormone Analogue ◽  
Relevant Variables

AbstractExperiments were performed to determine the role of body weight in the response of last instar western spruce budworm, Choristoneura occidentalis Freeman, to a topically applied juvenile hormone analogue (JHA), Ro 13-5223 (Ethyl [2-(p-phenoxyphenoxy)ethyl] carbamate). The response of males in weight classes from 50 to 130 mg was not proportional to their body weight; susceptibility increased drastically in heavier larvae. The susceptibility of females increased in proportion to their body weight. The results of these experiments suggest that future investigations of JHA effectiveness in last instar Lepidoptera should consider both weight and sex as possible relevant variables. Age of the last instar may not, in itself, be an adequate measure by which to quantify JHA effects.

JOINT ACTION OF A JUVENILE HORMONE ANALOGUE WITH BENZOYLPHENYLUREAS INGESTED BY WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS (LEPIDOPTERA: TORTRICIDAE)

1984 ◽  
Vol 116 (8) ◽  
pp. 1063-1068 ◽  
Author(s):  
Jacqueline L. Robertson ◽  
Kimberly C. Smith ◽  
Jeffrey Granett ◽  
Arthur Retnakaran
Keyword(s):  
Simple Model ◽  
Juvenile Hormone ◽  
Spruce Budworm ◽  
Choristoneura Occidentalis ◽  
Independent Action ◽  
Western Spruce Budworm ◽  
Hormone Analogue ◽  
Juvenile Hormone Analogue ◽  
Response Range ◽  
Bay Sir 8514

AbstractMixtures of the juvenile hormone analogue (JHA) methoprene and each of three benzoylphenylureas (BPUs) were fed to sixth-instar western spruce budworm, Choristoneura occidentalis Freeman. The BPUs tested were diflubenzuron, BAY SIR 8514 (N-[(trifluoromethoxy)phenyl]carbamoyl-2-chlorobenzamide), and EL-127063 (N-[[[5-(4-bromphenyl)-6-metnyl-2-pyrazinyl]amino]carbonyl]-2-chlorobenzamide). Mixtures consisted of JHA:BPU combined in 1:9 proportions. Ingestion of methoprene combined with BAY SIR 8514 or diflubenzuron resulted in significantly lower mortality than expected under a simple model of uncorrelated, independent action. Ingestion of the mixture of methoprene and EL-127063, however, resulted in significantly enhanced toxicity over the upper response range (> 50% mortality).

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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