Cate MacGregor shows how Joshua tree’s super-specialized pollinators are adapted to climate, too

Master’s student Cate MacGregor successfully defended her dissertation this morning. Cate’s thesis project uses RADseq data to look for evidence of local adaptation to climate in populations of moths so specialized that we know next to nothing about their lives when they’re not on their host plant — the pollinators of Joshua trees.

Working from samples collected by Master’s alum Alby Dang, Cate learned RADseq library preparation with our collaborators in Chris Smith’s lab at Willamette University, flying up to do the work just before we shut down operations in the early days of the 2020 COVID-19 outbreak. The data she collected in that one lucky trip expanded on samples the Smith Lab had previously sequenced, and Cate applied it to call single-nucleotide polymorphism (SNP) loci in populations of the two species of yucca moths that pollinate eastern and western Joshua trees. She conducted genotype-environment association testing to find SNPs aligned with differences in temperature and precipitation across the two moth species’ ranges; and she used the BEDASSLE framework to quantify the degree to which the moths movement across their ranges is limited by local adaptation to climate differences.

In addition to her thesis work, Cate made major contributions to sample collection and lab work for the Joshua Tree Genome Project. She’s staying on for the summer to get her thesis ready for submission to a journal, and then she’ll be enrolling in an accelerated K-12 teaching accreditation program to pursue the passion for science education she discovered as a graduate teaching assistant.