DISSERTATION RESEARCH: Consequences of Indirect Defensive Traits on Microbial Diversity

Cornell University, Ithaca NY

Investigators

Abstract

Plants have evolved many interesting ways to defend themselves against their enemies, pathogens (generally microbes such as fungus) and herbivores (insects, for example). One approach plants use for defense is to attract species that suppress pathogens or herbivores -- enemies of their enemies -- by offering food or shelter. This research explores the effectiveness of providing food and shelter through experiments that focus on mites that eat harmful fungi on leaves. The effectiveness of providing food will be explored by experiments with extrafloral nectaries, small glands on leaves that secrete sugar and attract mites and ants. The effectiveness of providing shelter will be explored by experiments with leaf domatia, tiny structures on the undersides of leaves that house fungus-eating mites. The traits studied in this work, extrafloral nectarines and domatia, are very widespread: they are present on many common trees and popular ornamental shrubs, as well as on crop plants such as cotton, coffee and grape. Additionally, the interactions between these traits, mites and fungi are used in agriculture as a way to decrease plant pathogen damage without the use of harmful fungicides. Thus, understanding their evolution and ecology can inform how we manage species interactions in our local ecosystems as well as in our crops and urban landscapes. Undergraduate students will be involved in this project and mentored in research. Likewise, a program is in place to communicate the work to middle school students.