Ecosystem Engineers As Evolutionary Drivers: Exploring Host-Parasite Diversification in Aciurina (Diptera: Tephritidae) Insect Gall Communities

Ecosystem engineers shape communities by modifying their environments, yet their role in driving diversification is not well understood. Gall-inducing insects, as both ecosystem engineers and symbionts with plants, create complex ecological networks that provide a powerful system for studying host-parasite co-diversification and community assembly. This dissertation investigates the ecological and evolutionary consequences of gall induction in Aciurina (Diptera: Tephritidae) on Asteraceae hosts in North America. By characterizing the functions within communities, examining the adaptive significance of morphology, resolving species boundaries of hyperdiverse associated clades through integrative taxonomy, and analyzing tri-trophic patterns of host-associated differentiation, this work reveals how the evolution of gall induction contributes to biodiversity at multiple levels. Findings highlight the role of interactions in diversification, the evolutionary significance of symbiotic associations, and the mechanisms underlying specialization in gall-associated systems. This research advances our understanding of how symbiotic ecosystem engineers shape both ecological and evolutionary processes.