Is monophagy an evolutionary dead end? Evidence from Euro-Mediterranean Chrysomelidae

Chrysomelidae is a large family of phytophagous insects that include species with different levels of specialization and width in term of exploited host plants spectrum: monophagy, oligophagy and polyphagy. With this study, we would like to address the following biological question: Is the evolutionary pathway of host plant exploitation towards specialization? For this purpose i) the types of phytophagy (i.e., monophagy, oligophagy and polyphagy) associated with 527 Euro-Mediterranean leaf beetles species will be defined using literature information and field observations on the host plants ii) a phylogeny of these species will be inferred using mitochondrial and nuclear markers (i.e., COI, 16S rRNA, EF-1, 18S rRNA), sequences will be mined from public repositories and de novo amplified; iii) the types of phytophagy will be reconstructed across the leaf beetles phylogeny, in order to define if the evolutionary pathway is towards specialization (i.e. from polyphagy to monophagy) or monophagy occurred randomly. Up to now, a database including the information on the host plants has been developed and used to define the types of phytophagy associated with each analysed species. Moreover, a dataset of COI sequences belonging to the 527 Chrysomelidae species considered have been created (277 mined and 250 de novo sequenced); 30 EF-1, 204 16S rRNA and 207 18S rRNA sequences have been mined from online repositories. DNA extraction and PCRs for completing the datasets of the selected markers are currently ongoing. The study will improve the knowledge on distribution and evolution of the types of phytophagy in Chrysomelidae and, in addition, it will be useful for understanding the evolutionary pathway of trophic specializations in phytophagous insects.