Environmental Signals, the Neuroendocrine System, and the Regulation of Larval Diapause in the Southwestern Corn Borer, Diatraea grandiosella

2008 ◽  
pp. 259-275 ◽  
Author(s):  
G. Michael Chippendale
Keyword(s):  
Neuroendocrine System ◽  
Diatraea Grandiosella ◽  
Corn Borer ◽  
Environmental Signals ◽  
Larval Diapause ◽  
Southwestern Corn Borer

Diapause of the southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera, Pyralidae): effects of a juvenile hormone mimic

1976 ◽  
Vol 66 (1) ◽  
pp. 75-79 ◽  
Author(s):  
G. M. Chippendale ◽  
C.-M. Yin
Keyword(s):  
Single Dose ◽  
Juvenile Hormone ◽  
Diatraea Grandiosella ◽  
Corn Borer ◽  
Larval Diapause ◽  
Pest Insects ◽  
Juvenile Hormone Mimic ◽  
Lepidoptera Pyralidae ◽  
Southwestern Corn Borer ◽  
Topical Applications

AbstractTopical applications of a juvenile hormone (JH) mimic induced and prolonged the mature larval diapause of the southwestern corn borer, Diatraea grandiosella Dyar. The onset of this diapause is marked by an ecdysis from a spotted to an immaculate morph. A high percentage of spotted non-diapause larvae treated with a single dose of a JH mimic moulted into the immaculate morph and became dormant. Similar treatments of diapause larvae led to a reversion to the spotted morph, but the larvae remained dormant. These results imply that diapause larvae contain an intermediate JH titre. A use for JH mimics in disrupting the seasonal phenology of pest insects with larval dormancies is suggested.

Horomonal control of larval diapause and metamorphosis of the southwestern corn borer Diatraea grandiosella

1976 ◽  
Vol 64 (2) ◽  
pp. 303-310
Author(s):  
C. M. Yin ◽  
G. M. Chippendale
Keyword(s):  
Juvenile Hormone ◽  
Corpora Allata ◽  
Hormonal Activity ◽  
Diatraea Grandiosella ◽  
Corn Borer ◽  
Larval Diapause ◽  
Last Stage ◽  
Southwestern Corn Borer ◽  
The Brain

Changes in haemolymph juvenile hormone (JH) concentrations of larvae of the southwestern corn borer, Diatraea grandiosella, were used to estimate the activity of the corpora allata. The haemolymph of penultimate nondiapause instars contained a maximum JH titre of 3000 Galleria units (GU)/ml, whereas the titre in the final instar had dropped to 140 GU/ml within 6 h of the ecdysis and continued to remain low. Corpora allata of last-stage non-diapause larvae therefore remain inactive. Some signal other than a rapidly declining JH titre in mid-instar triggers the release of ecdysiotropin because the pupal moulting cyclic did not become independent of the brain and ecdvsial glands until 4–25 and 4–75 days after the final larval ecdysis, respectively. Newly diapaused immaculate larvae had a haemolymph JH titre of ca. 1500 GU/ml. Three JH mimics applied to early last stage non-dispause larvae induced the formation of the immaculate dispause morph. The mimics did not activate the recipient's corpora allata, but elevated the function JH concentration, each having a different intrinsic hormonal activity. Threshold JH concentrations which control larval ecdyses, dispause maintenance, and metamorphosis are presented.

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