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Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low and high functional diversity in 40 streams on 6 continents and spanning 113° of latitude. Despite important variability in our dataset, we found latitudinal differences in the effect of litter functional diversity on decomposition, which we explained as evolutionary adaptations of litter-consuming detritivores to resource availability. Specifically, a balanced diet effect appears to operate at lower latitudes versus a resource concentration effect at higher latitudes. The latitudinal pattern indicates that loss of plant functional diversity will have different consequences on carbon fluxes across the globe, with greater repercussions likely at low latitudes.

Aquaculture plays a major role in curbing malnutrition and food insecurity. Nonetheless, aquaculture sustainability is threatened by expensive fish feeds due to the overreliance on fish meal (FM) as the main source of protein. Fish meal is not only expensive but also scarce due to declining capture fisheries and competition from other animal feed producers. This has prompted research on potential FM replacers, amongst them the black soldier fly (BSF) larvae (Hermetia illucens). The BSF larvae can effectively convert organic wastes into a potential valuable feed source, and its high nutritional content (crude protein of up to 64% dry matter) is vital for fish feed formulation. Nevertheless, there are no documented studies on the complete replacement of FM in the diets of fish using BSF larvae. Therefore, the current study reviewed 107 research publications related to BSF larvae vis-a-visfish feeds production to build capacity for existing theories, identify gaps, and suggest new and further research directions, based on the previous studies available in the area of larvae production and utilization in aquaculture nutrition. The study results are expected to help farmers make an informed decision on how to reduce the cost of fish production, increase yields, thus promoting food security, livelihoods, and ecological balance.

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