Fig. 3.

Adaptive radiation of specialized herbivorous beetles after the acquisition of PCWDEs from microbes. (A) Summary of beetle time tree showing 2 major independent origins of novel PCWDEs from bacteria and fungi and coincident net diversification rate increases among specialized herbivorous beetles (green background; summarized from Figs. 1 and 2): 1) along the stem of Buprestidae (Buprestoidea) and 2) along the stem of Phytophaga (Chrysomeloidea + Curculionoidea). Colorized boxes indicate the presence of candidate PCWDEs. The number of beetle species sampled that contain at least one PCWDE gene family member is indicated in each box. Empty/white boxes indicate a gene family was not observed. Beetle diets: detritivory (D), mycophagy (M), predation (Pr), herbivory (H), and unknown (?). Most data were obtained from ref. 6 and are ordered by decreasing prevalence. Percent herbivores >1% is shown to the nearest 5% and was estimated based on our collective knowledge of these beetle groups. (B) Unrooted phylogenetic trees for PCWDE gene families illustrating the taxonomic origins of beetle-encoded genes (SI Appendix, Figs. S15–S26 and Datasets S1–S3). The beetle groups represented in each gene tree are labeled. Leptinotarsa image courtesy of the USDA Agricultural Research Service/Scott Bauer, licensed under CC BY 3.0.