Action of Different Ecdysteroids on the Regulation of mRNAs for the Ecdysone Receptor, MHR3, Dopa Decarboxylase, and a Larval Cuticle Protein in the Larval Epidermis of the Tobacco Hornworm,Manduca sexta

1997 ◽  
Vol 107 (1) ◽  
pp. 84-97 ◽  
Author(s):  
Kiyoshi Hiruma ◽  
Detlef Böcking ◽  
René Lafont ◽  
Lynn M. Riddiford
Keyword(s):  
Manduca Sexta ◽  
Tobacco Hornworm ◽  
Dopa Decarboxylase ◽  
Ecdysone Receptor ◽  
Larval Cuticle ◽  
Cuticle Protein

Physiology of Pupal Ecdysis in the Tobacco Hornworm, Manduca Sexta: I. Evidence for Control by Eclosion Hormone

1980 ◽  
Vol 88 (1) ◽  
pp. 327-338 ◽  
Author(s):  
JAMES W. TRUMAN ◽  
PAUL H. TAGHERT ◽  
STUART E. REYNOLDS
Keyword(s):  
Biological Activity ◽  
Manduca Sexta ◽  
Tobacco Hornworm ◽  
Endocrine Control ◽  
Pupal Development ◽  
Larval Cuticle ◽  
Eclosion Hormone ◽  
Quantitative Bioassay

The time of pupal ecdysis in Manduca sexta can be accurately predicted by the appearance of external markers late in pupal development. Eclosion hormone injections resulted in premature ecdysis of staged pharate pupae. The latency between injection and initiation of ecdysis movements was inversely correlated with dosage and served as the basis for a sensitive, rapid, and quantitative bioassay for the hormone. Behavioural responsiveness to the hormone arose about 8 h before normal ecdysis at 23 °C. When insects were injected at these early times the larval cuticle was not sufficiently digested to allow its rupture and these animals remained permanently trapped inside the larval cuticle. Measurement of eclosion hormone in the blood of pharate pupae showed the appearance of biological activity in the blood about 30 min before the onset of ecdysis. It is concluded that pupal ecdysis is under endocrine control and that the hormone involved is likely to be the eclosion hormone.

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