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.
Plants have evolved many interesting and important ways to defend themselves against pests. One way that has evolved many times is to attract the enemies of pests, which provide protection by consuming herbivores or pathogens. The plant attracts and retains bodyguards by offering a reward, frequently food or housing. The research supported by this award was designed to explore how these food and housing rewards impact the microbial communities living on plant leaves via the attraction of fungus eating mites. The results of the experiments gave us a number of new insights into how mites and fungal communities vary across species with two common reward-traits: (1) extrafloral nectaries, small glands on leaves that secrete sugar as a food reward, and (2) leaf domatia, tiny structures on the undersides of leaves that provide housing to mites. In particular, we learned that the abundance and diversity of fungi living on the leaves of closely related plants vary across the presence and absence of these important reward traits. The traits studied in this work are highly 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 may be utilized 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.
