Identification of tissues showing the lowest tolerance to freezing in larvae of the rice stem borer, Chilo suppressalis

Yohei Izumi, Shoji Sonoda, Hideya Yoshida, Hisaaki Tsumuki

    Research output: Contribution to journalArticlepeer-review

    12 Citations (Scopus)


    Even though overwintering larvae of the rice stem borer, Chilo suppressalis, are freeze-tolerant, they cannot survive below -30°C. Furthermore, non-diapausing larvae cannot survive freezing. However, the cause of death due to freezing is unclear. To identify the cause of death by freezing in larvae, those tissues most injured by low temperatures are identified using the vital stain trypan blue. In overwintering larvae, the midgut of dead larvae stains blue, and remarkable colour density differences between dead and surviving larvae are observed in the midgut. In nondiapausing larvae incubated at -10°C for several hours, the fat body of dead larvae is strongly stained. Furthermore, increases in mortality with treatment time correspond with increases in the area of the fat body stained. Sterile nondiapausing larvae with lower supercooling points, below -20°C, do not freeze at -10°C and survive the treatment. However, all the larvae die when subjected to inoculative freezing at -10°C, and the fat body stains blue. These results suggest that the midgut in overwintering larvae and the fat body in nondiapausing larvae have the lowest tolerance to freezing.

    Original languageEnglish
    Pages (from-to)324-331
    Number of pages8
    JournalPhysiological Entomology
    Issue number4
    Publication statusPublished - Dec 1 2005


    • Chilo suppressalis
    • Fat body
    • Freeze-tolerance
    • Midgut
    • Trypan blue

    ASJC Scopus subject areas

    • Physiology
    • Ecology, Evolution, Behavior and Systematics
    • Insect Science


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