By Isabella Lin, Ryan Gabelman, Hillary Poalacin, Luke Sparreo

Apr 28 2026

Sugar maple (Acer saccharum) is a common tree in northeastern North American forests that supports numerous ecological interactions on its leaves and bark. Among these interactions are associations with mites that inhabit the leaf. Certain mite species induce the formation of galls, which are abnormal growths that develop when mites manipulate plant cells as they feed and reproduce. These structures provide shelter and nutrition for the mites while altering the structure of the leaf. Although gall formation may appear damaging, the overall impact on A. saccharrum is often limited. Just as in the riverbank grape, galls may also host predatory mites that feed on herbivorous species, creating a balanced microenvironment within the leaf. Through these associations with gall-forming mites, A. saccharum supports a diverse community of organisms that influence plant health and ecosystem dynamics. Herbarium specimens of gall-forming plants like A. saccharum can even preserve evidence of these relationships, allowing scientists to observe structural changes such as galls and leaf damage across different locations and time periods.