Extreme temperature events are a great challenge for most ectotherms, particularly for the immature stages of parasitoids, as they do not possess the ability to behaviourally thermoregulate. In this study, we measured the effect of an acute heat shock, combined with desiccation stress (34 °C and 35% r.h. during 10 h) during the mummy stage on several fitness‐related traits of emerging adults of the aphid parasitoid Aphidius colemani Viereck (Hymenoptera: Braconidae: Aphidiinae). Our results showed that the emergence rate was strongly affected by the heat shock (63 ± 2.3 vs. 96.1 ± 0.7% for stress vs. control conditions, respectively), and the resulting population was male biased. Heat stress reduced the lifespan of emerged parasitoids but had no effect on fat reserves and female size. Egg load at emergence and parasitism rate were also reduced by heat treatment. The antennal symmetry was disturbed by the heat treatment, and stressed individuals had reduced mating success compared to control parasitoids. Specifically, time before wing fanning, a typical male courtship behaviour, was significantly longer in parasitoid pairs involving females that had emerged from heat‐treated mummies. Additionally, olfactometry tests on experimental females indicated that their response to host odour was similar to that of control individuals, but they required a longer time for perception. These results highlight that exposure to high temperatures during the mummy stage has cumulative detrimental effects that may strongly impact parasitoid populations under natural conditions and hinder the success of biological control programs.

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The dose-response effects of gamma radiation on the carob or date moth Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) were studied as a basic requirement for the initiation of an SIT/F1 sterility program. In this study, the effect of gamma radiation was determined on fecundity, egg hatch, longevity, and level of inherited sterility in the carob moth. Newly emerged virgin male and female carob moth adults were exposed to increasing irradiation doses (100, 150, 200, 250, 300, and 350 Gy) to determine the effective dose of gamma rays capable of sterilizing male and female adults of the carob moth. Parental fecundity and longevity was affected by increasing irradiation dose. The results indicated that a dose of 350 Gy could completely sterilize carob moth males. No larvae hatched from eggs deposited by 300 Gy irradiated females. The data indicate that 300 Gy was the fully sterilizing dose for female and sub-sterilizing dose for male carob moth. Radiation-induced deleterious inherited effects in offspring from irradiated males and females were expressed as reduction in fecundity, egg hatch, longevity, and decreased adult emergence over subsequent generations.

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