Some Attributes of Cold Hardiness of the Gregarious Ectoparasitoid Colpoclypeus Florus (Hymenoptera: Eulophidae)

Author： Milonas Panagiotis G. Savopoulou-Soultani M.

ISSN： 1742-0644

Source： Cryoletters, Vol.26, Iss.6, 2005-11, pp. : 395-399

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Abstract

Cold hardiness of diapause and non-diapause larvae of the parasitoid Colpoclypeus florus Walker (Hymenoptera: Eulophidae) was examined in the laboratory. Mean supercooling point (SCP) for diapausing larvae was −26.7°C and for non-diapausing larvae immediately after their larval development, was −16.2°C. Mean SCP for non-diapause larvae at the prepupa stage was −19.1°C. A short period of acclimation (1 week at 5°C) had no influence on the mean SCPs of both diapause and non-diapause larvae. Pre-freeze mortality for diapause and non-diapause larvae was also studied. A constant exposure of diapause larvae to −6°C resulted in high mortality (70.7%) after a period of 40 days. In contrast, 6 days at −6°C were sufficient to cause the same level of mortality in non-diapause larvae. After exposure of 15 days at −9°C, mortality for non-diapause larvae was 70%, whereas after 20 days at the same temperature mortality of diapause larvae was 25%. The importance of these findings for the cryobiology of C. florus is discussed.