# Unveiling Weevil Diversity Drivers and Cryptic Species on the Qinghai–Xizang Plateau

## TL;DR

This study reveals high weevil diversity on the Qinghai–Xizang Plateau, with uneven distribution and potential cryptic species, emphasizing the need for further biodiversity research.

## Contribution

The study identifies elevation range as the key driver of weevil diversity and uncovers cryptic species within 11 morphological species using DNA barcoding.

## Key findings

- Weevil diversity on the Qinghai–Xizang Plateau exceeds that of vertebrates and is concentrated in eastern and southern regions.
- Elevation range is the most significant factor influencing weevil species diversity.
- DNA barcode analysis suggests cryptic species within 11 morphological species.

## Abstract

Based on a study of weevils (Curculionoidea) on the Qinghai-Xizang Plateau, this research found their species diversity to be higher than that of vertebrates, with an uneven distribution concentrated in the eastern and southern regions. Elevation range emerged as the most critical factor influencing diversity. DNA barcode analysis also suggested the potential existence of cryptic species within 11 morphological species. These findings enhance the understanding of biodiversity in understudied taxa on the plateau and highlight the need for further multidisciplinary research.

Understanding patterns and mechanisms of species diversity is one fundamental issue in biogeography and ecology. As a critical region for biodiversity, the Qinghai-Xizang Plateau (QXP) still has unclear distribution patterns and drivers for cryptic, understudied taxa such as Curculionoidea. Here, we collected the distribution data of Curculionoidea on the QXP to analyze their diversity patterns and influencing factors, and compiled a DNA barcode dataset to uncover cryptic diversity. This comprehensive dataset encompasses 671 Curculionoidea species across 223 genera, demonstrating a level of diversity that surpasses that of certain vertebrate groups. We also observed an unbalanced biogeographic pattern of diversity, with a concentration of species in the eastern and southern regions and a scarcity in the northern and central areas of QXP. Further analysis showed that the elevation range is the most important factor influencing the diversity of Curculionoidea. In addition, based on 1147 COI-5′ barcode sequences from 217 species, we found that 11 morphological species may contain cryptic species based on DNA barcode datadset. Our findings significantly enhance the current understanding of cryptic biodiversity patterns among understudied taxa in the QXP, while simultaneously highlighting persistent knowledge gaps in characterizing the plateau’s full ecological complexity.