Wed, Aug 17, 2022: 8:30 AM-8:45 AM
513D
Background/Question/MethodsHeat waves are becoming more frequent with climate change, and their impact on lower andhigher trophic levels can differ. Higher trophic levels, such as predators and parasitoids, are predicted tobe more strongly affected by heat waves than herbivores because they may have smaller thermal windowsand because of altered ecological interactions with lower trophic levels. We tested the effects of heat wavesof varying intensity (36–42°C), imposed for 4 h during five consecutive days on the egg stage of an invasiveherbivore, the brown marmorated stink bug (Halyomorpha halys), and on various developmental stages ofits parasitoid, Trissolcus japonicus.
Results/ConclusionsHalyomorpha halys eggs had lower hatching success and fewer nymphs emerging with increasing intensity of heat stress, while exposure during the egg and larval stages ofT. japonicus did not decrease adult emergence rates. Heat waves increased developmental time of parasitoidsand decreased adult emergence when pupal stages were exposed. Adult parasitoids experiencingheat stress had lower survival, but their parasitism success overall was not affected. In addition, wedetected transgenerational effects, whereas emergence success and the number of adult parasitoids emergingin the second generation declined when the parental generation was exposed to 42°C. Contrary toexpectations, the results suggest that H. halys may be more sensitive to heat stress than T. japonicus, at leastduring early development. Our findings indicate that biological control services provided by T. japonicuscan be maintained in the face of increasing heat wave events and point to the importance of following populationsbeyond the first generation to better understand the long-term consequences of heat stress.
Results/ConclusionsHalyomorpha halys eggs had lower hatching success and fewer nymphs emerging with increasing intensity of heat stress, while exposure during the egg and larval stages ofT. japonicus did not decrease adult emergence rates. Heat waves increased developmental time of parasitoidsand decreased adult emergence when pupal stages were exposed. Adult parasitoids experiencingheat stress had lower survival, but their parasitism success overall was not affected. In addition, wedetected transgenerational effects, whereas emergence success and the number of adult parasitoids emergingin the second generation declined when the parental generation was exposed to 42°C. Contrary toexpectations, the results suggest that H. halys may be more sensitive to heat stress than T. japonicus, at leastduring early development. Our findings indicate that biological control services provided by T. japonicuscan be maintained in the face of increasing heat wave events and point to the importance of following populationsbeyond the first generation to better understand the long-term consequences of heat stress.