Aldo A. Arellano

5032 BSB

1105 N University Ave

Ann Arbor, MI 48109

I am currently a postdoctoral fellow in molecular ecology affiliated with the Institute for Global Change Biology, the Cooperative Institute for Great Lakes Research, and the Duffy Lab at the University of Michigan. I am interested in how trophic interactions shape community ecology across macroscopic and microscopic scales. I use food webs and symbioses as models to explore these topics.

By pairing field-based approaches and in situ manipulations with laboratory experiments I can selectively poke and prod communities of microorganisms, host-microbe interactions, and trophic complexity to understand basic features of ecological networks and function across diverse environments.

My experience in research began in limnology and aquatic ecology, where I studied the spatio-temporal dynamics of seasonal cyanobacteria blooms. From then I caught the “research bug” and moved on to work in marine microbial ecology where I adopted a systems-level perspective for understanding the emergent properties of ecosystems. In my PhD, I used a novel mosquito model (Wyeomyia smithii) to elucidate basic features of host-microbe-environment interactions in Dr. Kerri Coon’s lab at the University of Wisconsin-Madison. Recently, I am also interested in the role of microorganisms in the evolution of diverse host life histories and how microbial symbionts may impact host resilience and phenotypic plasticity. In my current role I study animal-microbe interactions and food web dynamics in the Great Lakes and inland lakes of southeastern Michigan with an emphasis on zooplankton.

selected publications

Host-mediated niche construction of bacterial communities in an aquatic microecosystem

Aldo A Arellano, Journey L Prack, and Kerri L Coon

The ISME Journal, Oct 2025

Abs DOI

Microbes coordinate homeostasis in host-associated and environmental ecosystems alike, but the connectivity of these biomes is seldom considered. Hosts exert controls on the composition and function of their internally associated symbionts, but an underappreciated modality of microbiome curation is external to the host through changes to the environmental species pool from which they recruit microbial symbionts. Niche construction theory describes how organisms alter their environment and the selective landscape of their offspring and conspecifics. We hypothesize that host-driven manipulation of environmental microbial communities is an underexplored form of this concept. Using the pitcher plant mosquito (Wyeomyia smithii) as a model, we tested how hosts shape microbial communities across developmental stages and gradients of pre-existing community complexity. We report three lines of evidence supporting host-mediated niche construction, leveraging amplicon sequencing and microbiota manipulation experiments with germ-free (axenic) and selectively recolonized (gnotobiotic) mosquitoes. First, single female egg-laying assays showed repeatable adult inoculation of sterile water with beneficial bacteria capable of sustaining robust larval development. Second, increasing larval density in assays inoculated with complex, field-derived microbial communities selected for environmental and host-associated bacteria that correlated with increased larval fitness. Finally, exposing axenic larvae to mixtures of parentally and environmentally derived microbiota demonstrated that prior conditioning by conspecifics enhanced offspring fitness. Although the bacterial taxa associated with mosquito structuring varied, members of the Actinobacteriota and Acetobacteraceae were consistently associated with increased fitness. Overall, our results provide an example of host-mediated niche construction to favor environmental microbial communities that positively impact host fitness.