The California Conservation Genomics Project (CCGP): Characterizing the diversity of Tamalia aphid galls as part of California’s landscapes

The University of California Conservation Genomics Project (CCGP) has three principal goals: 1) to identify biological populations harboring the greatest genomic diversity across the state’s diverse ecological regions (eco-regions); 2) to identify those eco-regions likely to be resilient in the face of climate change and novel land-use patterns; 3) to amass data on the genomic robustness of ecological keystone species. We argue that Tamalia coweni (Aphididae), by inducing galls on a range of Arctostaphylos (Ericaceae) shrubs in California’s landscapes, represents a keystone species. As seen in the wide variety of gall shape, size, and texture among host plant species, gall induction by Tamalia aphids is a unique manifestation of gene expression in both host plant and insect. As a keystone species, Tamalia coweni galls support a variety of associated arthropods, including socially parasitic Tamalia inquiline aphids, two specialist dipteran predators, opportunist predatory anthocorid bugs, gregarious Aprostocetus larvae (Eulophidae), and thigmotactic thrips. In an effort to characterize the genetics of T. coweni at a landscape level, we are creating a chromosome-level reference genome for T. coweni. At a population level, we are applying genome re-sequencing techniques for sampling Tamalia galls comprehensively across California’s eco-regions. Ultimately we will use these data to identify the regions and populations with the highest potential for safeguarding genetic and ecological diversity in perpetuity. Here we present an update on the project.