Heat wave-induced trans-generational modifications in the predatory mite Amblydromalus limonicus

Abstract: Trans-generational modifications may allow populations to keep pace with rapidlychanging thermal conditions such as the occurrence of heat waves by phenotypic adjustment ina temporally adequate manner. This assumption was tested with the offspring of the predatorymite Amblydromalus limonicus Garman and McGregor deriving from parents experiencingcommon summer conditions or heat wave conditions. The effects of the thermal rearingconditions (common summer conditions, heat wave conditions) during juvenile developmenton survival, age and size of the offspring were evaluated. The survival rates were high and notaffected by the thermal conditions. Non-plastic trans-generational modifications resulted infaster juvenile development of offspring deriving from parents experiencing heat waveconditions. Plastic trans-generational modifications resulted in larger daughters, but not sons,when the offspring thermal conditions corresponded to the parental thermal conditions Fastdevelopment should reduce the time slot of exposure to heat waves and large individuals shouldbe less vulnerable to dehydration and overheating. Thus, we assume that phenotypicmodifications transferred from the parents to the offspring could be a mechanism for arthropodsto buffer and tolerate the usually detrimental effects of heat waves.