Karpova S.G., Reznik S.Ya. 2003. Temperature dependency of the daily pattern of adult eclosion in two Trichogramma species (Hymenoptera, Trichogrammatidae). Annual Reports of  Zoological Institute RAS. Vol. 299: 61-68.

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A comparative investigation of temperature effects on the daily pattern of adult eclosion was carried out with two species of egg parasitoids, T. embryophagum (Hartig) and T. principium Sugonjaev et Sorokina. The experiment was conducted under the same photoperiod (LD=12:12) but different constant temperature: 15, 20 or 25C. In both species, eclosion during dark period was week under all temperature regimes, most parasitoids eclosed within first 4 hours of photophase. Pattern of eclosion depended on temperature: the lower was the temperature, the higher was a percentage of adults emerging at the middle of the photophase. T. embryophagum changed the rhythm under low temperature conditions to a greater extent than T. principium. The latter species, in turn, responded to highest temperature level (25C) by strongly intensified eclosion in dark period, in contrast to T. embryophagum. Such a species-specific temperature dependency correlated with climatic conditions of the sites from which the strains were originated.