We here review the current knowledge on the trophic ecology of stoneflies, an aquatic insect group of substantial ecological importance in lotic systems. We provide information on the feeding habits of nymphs and adults of the different families and highlight those studies that support particularly interesting findings. Regarding nymphs, we discuss the state of the art on aspects such as foraging strategies and behaviours, food acquisition mechanisms, the existence or absence of electivity for certain trophic resources, and enzymatic activity and its relationship with the assimilation efficiency of food. For adults, we highlight the differential importance of feeding among taxa. For both nymphs and adults, we report what is known about their role in aquatic and terrestrial food webs. Finally, we present some of the gaps on the trophic ecology of these insects and provide some research agendas that could be carried out to fill them.

Biological invasions have increased significantly in response to global change and constitute one of the major causes of biodiversity loss. Insects make up a large fraction of invasive species, in general, and freshwaters are among the most invaded ecosystems on our planet. However, even though aquatic insects dominate most inland waters, have unparalleled taxonomic diversity and occupy nearly all trophic niches, there are almost no invasive insects in freshwaters. We present some hypotheses regarding why aquatic insects are not common among aquatic invasive organisms, suggesting that it may be the result of a suite of biological, ecological and anthropogenic factors. Such specific knowledge introduces a paradox in the current scientific discussion on invasive species; therefore, a more in-depth understanding could be an invaluable aid to disentangling how and why biological invasions occur.