Photoperiodic induction of larval diapause in a New Zealand leafroller moth, Planotortrix octo

Abstract

Larval development in Planotortrix octo Dugdale shows a photoperiodic response. The duration of all instars, and the total instar number are both higher under short days. Night interruption experiments show that these parameters are influenced by the position of the light pulse and not just by the amount of light available.

Larvae reared under short days also accumulate significantly more lipids in the 5th and 6th instar than long-day larvae, suggesting that a weak larval diapause response may exist in this species. This is the first suggestion of a diapause response in a phyllophagous New Zealand insect for which a year round food source is available.

Keywords:

• Photoperiodism
• Planotortrix octo
• Lepidoptera
• Tortricida
• diapause