The data was collected exposing Chironomus riparius to sediment spiked with 1µm polystyrene-based latex microplastic spheres, an environmentally realistic concentration of a pyrethroid pesticide (esfenvalerate), and a combination of both treatments. The larvae were observed at 10, 28 days and until the emergence, and Illumina Miseq sequencing of 16S bacterial DNA was performed to obtain the larvae microbiome. Effects on the life-history traits of the benthic-dwelling invertebrate and its microbiome were analyzed. The data could be reuse for meta-analysis related to microplastics effects in aquatic invertebrates.

There is growing evidence of widespread contamination of freshwater ecosystems with microplastics. However, the effects of chronic microplastic ingestion and its interaction with other pollutants and stress factors on the life-history traits and the host-microbiome of aquatic invertebrates are not well understood. This study investigates the effects of exposure to sediment spiked with 1µm polystyrene-based latex microplastic spheres, an environmentally realistic concentration of a pyrethroid pesticide (esfenvalerate), and a combination of both treatments on the life-history traits of the benthic-dwelling invertebrate, Chironomus riparius and its microbial community. The chironomid larvae were also exposed to two food conditions: abundant or limited food in the sediment. The microplastics and esfenvalerate had negative effects on adult emergence and survival, and these effects differed between the food level treatments. The microbiome diversity and the relative abundance of the main phyla were significantly affected by the exposure to microplastics, but only in the high food level treatment. Although the combined exposure to microplastics and esfenvalerate showed some negative effects on survival and emergence, there was little evidence for additive effects when compared to the single exposure. The food level affected all life-history traits and the microbiota, and lower food levels intensified the negative effects of the exposure to microplastics, esfenvalerate and their combination. We discuss possible interactions between microplastics, pollutants and food levels on both the life-history traits and the host-microbiome, and also how direct effects on the microbiome might affect the life-history traits of the host indirectly. Our study highlights the importance of investigating possible additive and synergic activities between stressors to understand the effects of pollutants in the life story traits and host-microbiome.