Novel Phenoxy Juvenile Hormone Analog (Pyriproxyfen) Suppresses Embryogenesis and Adult Emergence of Sweetpotato Whitefly (Homoptera: Aleyrodidae)

1992 ◽  
Vol 85 (6) ◽  
pp. 2113-2117 ◽  
Author(s):  
I. Ishaaya ◽  
A. R. Horowitz
Keyword(s):  
Juvenile Hormone ◽  
Adult Emergence ◽  
Sweetpotato Whitefly ◽  
Juvenile Hormone Analog ◽  
Hormone Analog

EFFECTS OF ECDYSONES, JUVENILE HORMONE ANALOGS, AND 6-OXOOCTANOIC ACID ON THE DEVELOPMENT OF THE MOSQUITO, CULEX TARSALIS (DIPTERA: CULICIDAE)

1974 ◽  
Vol 106 (1) ◽  
pp. 79-85 ◽  
Author(s):  
P. I. Ittycheriah ◽  
M. S. Quraishi ◽  
E. P. Marks
Keyword(s):  
Juvenile Hormone ◽  
Topical Treatment ◽  
Adult Emergence ◽  
Fourth Instar ◽  
Culex Tarsalis ◽  
Juvenile Hormone Analog ◽  
Hormone Analog ◽  
High Doses ◽  
Hormone Analogs ◽  
Very High

AbstractEggs, larvae, and pupae of Culex tarsalis Coquillett were treated with ecdysones, juvenile hormone analogs, and 6-oxooctanoic acid. Effects of these agents on mortality, induction of supernumerary stages, and adult emergence were determined. Topical treatment of eggs with CRD9499 (a juvenile hormone analog), β-ecdysone, and 22-isoecdysone caused a reduction in adult emergence. Treatment of fourth-instar larvae with these chemicals not only induced mortality but also caused the formation of supernumerary intermediate stages. Larvae of C. tarsalis were very susceptible to CRD9499, but pupae were resistant. The ecdysones caused some mortality but only at very high doses and would thus be of little use as larvicides. 6-Oxooctanoic acid caused high rates of mortality at 0.001 M concentrations.

scholarly journals Regulation of metamorphosis in neopteran insects is conserved in the paleopteran Cloeon dipterum (Ephemeroptera)

2021 ◽  
Vol 118 (34) ◽  
pp. e2105272118 ◽  
Author(s):  
Orathai Kamsoi ◽  
Alba Ventos-Alfonso ◽  
Fernando Casares ◽  
Isabel Almudi ◽  
Xavier Belles
Keyword(s):  
Juvenile Hormone ◽  
Molecular Analysis ◽  
Nymphal Instar ◽  
Morphological Studies ◽  
Flying Insects ◽  
Juvenile Hormone Analog ◽  
Hormone Analog ◽  
Two Stages ◽  
Cloeon Dipterum ◽  
Hormonal Treatments

In the Paleozoic era, more than 400 Ma, a number of insect groups continued molting after forming functional wings. Today, however, flying insects stop molting after metamorphosis when they become fully winged. The only exception is the mayflies (Paleoptera, Ephemeroptera), which molt in the subimago, a flying stage between the nymph and the adult. However, the identity and homology of the subimago still is underexplored. Debate remains regarding whether this stage represents a modified nymph, an adult, or a pupa like that of butterflies. Another relevant question is why mayflies have the subimago stage despite the risk of molting fragile membranous wings. These questions have intrigued numerous authors, but nonetheless, clear answers have not yet been found. By combining morphological studies, hormonal treatments, and molecular analysis in the mayfly Cloeon dipterum, we found answers to these old questions. We observed that treatment with a juvenile hormone analog in the last nymphal instar stimulated the expression of the Kr-h1 gene and reduced that of E93, which suppress and trigger metamorphosis, respectively. The regulation of metamorphosis thus follows the MEKRE93 pathway, as in neopteran insects. Moreover, the treatment prevented the formation of the subimago. These findings suggest that the subimago must be considered an instar of the adult mayfly. We also observed that the forelegs dramatically grow between the last nymphal instar, the subimago, and the adult. This necessary growth spread over the last two stages could explain, at least in part, the adaptive sense of the subimago.

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