Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Aspects of overwintering in the cabbage armyworm, Mamestra brassicae (Lepidoptera, Noctuidae) I. Supercooling points and contents of glycogen and trehalose in pupae.

Abstract

The supercooling ability and accumulation of trehalose in pupae of the vegetable pest Mamestra brassicae was investigated in the laboratory. The supercooling point (by spontaneous freezing) was about -20.0°C in both diapausing and non-diapausing pupae. The supercooling ability was considerably reduced by contact moistuure. Pupae began to freeze at -4°C in muddy water and at -4.9 to -7.8°C in soil of various water contents. Trehalose content in diapausing pupae increased with days after pupation, attaining a maximum within 30 days with a concomitant decrease of glycogen. Further, trehalose content tended to decrease with incubation (at 22°C) of diapausing pupae kept at 4°C for 40 days. In non-diapausing pupae, trehalose accumulated less but the content was slightly increased over that in prepupae. Non-diapausing pupae developed a supercooling ability at a level comparable to that in diapausing pupae despite poorer trehalose accumulation. It is concluded that the supercooling ability in M. brassicae is probably determined by properties independent of trehalose accumulation.