Gene expression of L. basale in response to multiple stressor pulses

The degradation of freshwater ecosystems and decline in aquatic biodiversity is strongly associated with intensive land-use. Agricultural stressors such as pesticide contamination or increased fine sediment load can interact in complex ways and their combined effects are poorly understood. In this study, single and combined effects of the insecticide chlorantraniliprole in three different concentrations and increased fine sediment load on the transcriptional profile of the trichopteran Lepidostoma basale was assessed. Mainly antagonistic stressor interactions at the transcriptomic level were identified, probably because the insecticide adsorbs to fine sediment particles, reducing its bioavailability for shredder organisms such as L. basale. A strong insecticide induced effect in the trichopteran L. basale was observed, which is closely related to the insecticide's target group, i.e. Lepidoptera. However, gene regulatory responses were not related to a disruption of the calcium homeostasis, which is the described mode of action for chlorantraniliprole. In fact, mechanisms such as cellular detoxification and immune responses appear to play a more significant role, potentially evoked by oxidative stress in the mitochondria. If energetic trade-offs between these protective mechanisms and other physiological processes arise, long-term stressor exposure will have negative consequences for the whole population and stressor effects will be propagated to higher levels of biological organisation.