Investigating host plant associations of tortoise beetles through metabarcoding

• Grant number: 25/08074-0
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: September 01, 2025
• End date: February 28, 2026
• Field of knowledge: Biological Sciences - Ecology - Theoretical Ecology
• Principal Investigator: João Vasconcellos Neto
• Grantee: Felipe Capoccia Coelho
• Supervisor: Marianna Vieira dos Passos Simoes
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Senckenberg - Leibniz Institution for Biodiversity and Earth System Research, Germany
• Associated to the scholarship: 24/10368-0 - Phylogenetic influence on the structure of interaction networks between tortoise beetles (Cassidinae s. str., Chrysomelidae, Coleoptera) and their host plants., BP.MS

Abstract

Insect-plant interactions are ubiquitous in modern terrestrial ecology and are considered major drivers of insect diversification. Most of these interactions remain unknown because of the costly and time-consuming effort to assess them. Metabarcoding has proven to be a powerful tool for detecting arthropod-plant interactions using trace amounts of environmental DNA (eDNA) but has rarely been used to study insect-plant interactions directly. Its application could be particularly valuable for herbivorous insects that are rare, of low abundance, or difficult to observe - such as the tortoise beetles (Cassidinae s. str.). The challenges of direct observation have led to host plant records for only about 6% of known tortoise beetles' species, highlighting the need for alternative approaches to better understand their ecology and evolution. By applying metabarcoding, we can explore previously undetected interactions and improve our understanding of host plant use and potential shifts, offering a more comprehensive view of beetle-plant relationships, which also has important conservation implications. Recent monthly surveys in an Atlantic Forest reserve (Serra do Japi) have revealed new distributional records and host plant associations. However, to date, specimen identifications have not been confirmed by taxonomic specialists. Here, we aim to strengthen the baseline knowledge of Cassidinae diversity at Serra do Japi and to test and refine metabarcoding as a tool for investigating Cassidinae-plant interactions, allowing us to validate field and laboratory observations of hosts and providing insights into local food web dynamics. (AU)