NEW PUBLICATION: Systematic & exhaustive wood dissection: a standardized method for studying saproxylic insect communities in tropical rainforests

Saproxylic insects, insects dependent on dying or dead wood for survival, are very important in performing various ecosystem functions and services. Saproxylic insects range from Stag Beetle larvae that feed on decaying deadwood, to social parasites that live with ants nesting in deadwood. Other than carrying out nutrient cycling as they decompose deadwood, some saproxylic insects are pollinators (e.g. flower chafers and some longhorn beetles), and some are important food sources of other organisms (e.g. pangolin, sun bears and woodpeckers).

A big log like this decaying Rubroshorea pauciflora tree trunk is nurturing hundreds or thousands of saproxylic arthropod species! © Calvin Leung

Due to the dependence of saproxylic insects on deadwood habitats and forest ecosystems, they are one of the most vulnerable groups of organisms under land use change. However, we know very little about the diversity, natural history and habitat requirements of these threatened saproxylic insects, especially in the tropics. “We cannot protect what we don't know”. Like the naturalist Richard Louv once said, without knowing what are in our forests and what the fundamental ecological needs of these threatened insects are, these important saproxylic insects will disappear without us even noticing. Therefore, there is a urgent need for us to develop standardized collection methods that can associate the deadwood and the saproxylic insects collected, so that we can understand the characteristics of the deadwood substrates these saproxylic insects depend on.

In our new publication in Frontiers in Ecology and Evolution, we developed a workflow for carrying out wood dissection in a standardized way: the systematic and exhaustive wood dissection (SEWD) method. By exhaustively sampling 30 cm segment from decaying logs in 20 x 20 m experimental plots, we not only systematically surveyed the saproxylic insect communities in a fixed unit area of the forests, but also recorded the properties of the substrate the saproxylic insects were collected from, as well as any interspecific interactions that are important for the survival of certain species.

Graphical illustration of the SEWD method: 1. Mark all the sizable deadwood in the 20 x 20 m study plot. 2. Randomly extract a 30 cm long segment from each of the sizable log. 3. Dissect the deadwood thoroughly to collect any saproxylic insects. 4. Transfer the remaining sawdust into a Winkler extractor to obtain the missed saproxylic insects. Source: Leung et al. 2026

To test the effectiveness of our proposed SEWD method, we compared the saproxylic beetle communities captured with the SEWD method to the communities collected with the commonly-used ethanol-baited flight-interception traps (FITs). The saproxylic beetle communities collected with the SEWD method were dominated by predatory beetles. Specifically, ant-loving Rove Beetles from the subfamily Pselaphinae dominated the beetle species pool. The SEWD also collected many fossorial beetle species that are otherwise hard to collect with other collection methods, including: 1.) the rediscovery of a termitophilous scarab species Stereomera pusilla that was first discovered in Singapore in 1905 and had not been seen in Singapore until this project, 2.) the Telephone-phone Pole Beetles Micromalthus sp., the first member of the primitive beetle suborder Archostemata from Singapore, and many other undescribed species.

Examples of beetles collected with the SEWD method: Top left: Telephone pole beetle Micromalthus sp. adult. Top right: one the many ant-loving Rove Beetles. Bottom left: Stereomera pusilla adult wandering in a Schedorhinotermes termite nest. Bottom right: … upcoming new species discoveries! © Calvin Leung

This study demonstrated the importance of including exhaustive searching methods like the SEWD method in sampling small and fossorial tropical saproxylic insects. Importantly, the fine-scaled ecological data collected through the SEWD method increased specialist species discovery, and enables direct associations between saproxylic communities and the deadwood to be established. The ecological information of these threatened saproxylic insects will be crucial in future conservation.

This publication is only showing the surface layer of the findings from the SEWD dataset. There are many other upcoming discoveries regarding the community ecology of tropical saproxylic insects, as well as the natural history findings of many new species! Stay tuned for more discoveries from our tropical saproxylic insect project!

The paper is published as open-access at: https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2026.1855234/full