In our recent project on multiple stressors and springtails, we found that the soil fauna springtails are severely affected by exposure to currently used pesticides, and that the negative effects increase in severity with increasing temperature and drought. Strikingly, we find that sublethal concentrations of pesticides become lethal with increasing temperature, which was also demonstrated in ectotherms from other habitats.
As predicted a priori based on their different habitats we found much higher sensitivity in our surface-dwelling model springtail species Hypogastrura viatica than in the litter-dwelling Folsomia quadrioculata. However, we also found large differences in sensitivity between conspecific populations that differ in vital rates and climatic region, both under single and multiple stressors, with greater sensitivity in the temperate populations.
The master project will address if the increased negative effect of pesticides at higher temperatures is due to metabolic scaling, as metabolic processes increase with temperature until the optimal temperature is reached - or if the cost of repair mechanisms and homeostasis maintenance are increasingly affected by the continuous nervous overstimulation from the pesticide.
We focus on sublethal effects, which are more subtle and sensitive than mortality, occurring at lower and more environmentally relevant stress exposure levels, but still lead to substantial fitness changes.
Relevant papers from our previous research project: