picture of Lauren Johnston presenting his/her poster: LOCAL ADAPTATION IN DESERT MISTLETOE, PHORADENDRON CALIFORNICUM

Lauren Johnston , Dr. Jennifer Koop, Dr. Noah Whiteman


The purpose of this research is to determine how local adaptation affects survival of Desert Mistletoe, Phoradendron californicum. This work is performed with Dr. Jennifer Koop as part of a wider initiative within the laboratory of Dr. Noah Whiteman in the Ecology and Evolutionary Biology department to decipher how mistletoe infection patterns are affected by biological factors. Desert Mistletoeis a dioecious, hemiparasitic plant that is ubiquitous throughout the Sonoran Desert and is mostly parasitic on leguminous trees and shrubs. Desert mistletoe is almost exclusively dispersed by the Phainopepla (Phainopepla nitens), which consumes the fruits and deposits seeds after digestion upon tree limbs. We performed a reciprocal transplant experiment using desert mistletoe to test for local host adaptation. We collected mistletoe seeds from plants parasitizing Blue Palo Verde (Cercidium floridum) trees and Velvet Mesquite (Prosopis velutina) trees to create two donor pools of mistletoe seeds. We planted 240 seeds total on P. velutina and C. floridum. The most informative measure for differential survival will be whether the seeds remaining after the growing season succeed in forming a haustorial disk, which is necessary for mistletoe to access nutrients from its host plant. We expect that more seeds will form a haustorial disk when placed on the same host species from which they came. A survival analysis will determine if the host plant of the parent species affects the survival success of the offspring fruit.


The second vein of this project is to develop DNA microsatellites for Phoradendron californicum for use in deciphering genetic relationships between mistletoe plants across a landscape. These microsatellites will be used to determine if mistletoe plants from the same host and host species are more related to each other than mistletoe plants in a different host species. This together with the reciprocal transplant experiment data will provide insight into whether or not desert mistletoe exhibit local adaptation to a specific host race, a first step in speciation.


This research is partially funded by the University of Arizona Office of the Provost, The Laboratory of Dr. Noah Whiteman, and by a University of Arizona Honors College Study Grant. 

Conference Home | List of Abstracts | Photo Gallery