Aquatic Diptera are some of the most diverse and notable flies, impacting human health and providing ecosystem services. Despite the importance of aquatic Diptera, the evolution of aquatic life history and blood-feeding, are not sufficiently understood. Here, we examine the evolution of aquatic life histories and their associations with blood-feeding across Diptera. Aquatic and blood-feeding Diptera are phylogenetically conserved across the fly tree of life. We found evidence that the most recent common ancestor of Diptera likely had an aquatic life history. We discuss the rise of blood-feeding flies and specifically speculate on its relation to aquatic life history. Blood-feeding behaviors often occur in fly lineages that also have aquatic life histories, but not significantly. Evidence suggests that adaptations to larval aquatic life history were a precursor for flies expanding their diets to take blood meals.

We pooled together aquatic and blood feeding annotations from various peer-reviewed sources, such as Adler & Courtney 2019 and Wiegmann et al. 2011. More about the code here: https://github.com/ninapak256/aquatic-diptera.

Not all infraorder or superfamilies are labeled, and annotations were made for families (not based on the species from the tips) that included 1 species that had an aquatic life history or blood feeding behavior. Species in Table 3 are species based on the phylogeny from Wiegmann et al. 2011.