# Ecological Partitioning and Body Size Differentiation Enable Coexistence of Closely Related Semi‐Arboreal Therates Tiger Beetles (Coleoptera: Cicindelidae)

## TL;DR

This study shows how closely related tiger beetles coexist by differing in body size, mandible length, and habitat preferences.

## Contribution

The study provides evidence of character displacement and niche partitioning in coexisting tiger beetle species through multiple ecological dimensions.

## Key findings

- Coexisting tiger beetle species show significant differences in body size and mandible length.
- Larger species prefer larger leaves as hunting substrates.
- Spatiotemporal activity and foraging substrate preferences contribute to niche partitioning.

## Abstract

Mechanisms facilitating the coexistence of ecologically similar species remain a fundamental question in ecology. Here, we investigate niche partitioning among coexisting Therates tiger beetles by examining morphological differentiation, temporal activity, altitude distribution, and foraging substrate preferences. Across 40 sites, we analyzed 1065 specimens from six taxa, measuring body size and mandible length. Among these, 18 sites had coexisting species, while 22 had a single species. In total, four pairs of co‐occurring semi‐arboreal Therates species were noted. In 13 of the coexistence sites, we also measured leaf dimensions of primary hunting substrates. Our results reveal significant differences in body size and mandible length among coexisting species, with larger species preferring larger leaves. Notably, significant size differences between coexisting and noncoexisting populations of
T. fulvipennis bidentatus and T. coracinus coracinus support the role of character displacement in resource partitioning. Our findings suggest that morphological divergence, microhabitat preferences and spatiotemporal differentiation contribute to coexistence in the studied tiger beetle species. This study supports the niche partitioning hypothesis as a mechanism for coexistence among ecologically similar species. Understanding these mechanisms is critical for biodiversity conservation and management of riparian tropical ecosystems.

Our findings demonstrate that body size, mandible length, spatiotemporal activity, and foraging substrate preferences contribute to niche partitioning and species coexistence among Therates tiger beetles. Notably, significant size differences between coexisting and noncoexisting populations support the role of character displacement in resource partitioning. These results align with niche theory, suggesting that species coexist by differentiating their ecological niches across multiple dimensions.