Singapore's compact urban landscape hides a surprising wealth of insect life, and a groundbreaking study has now illuminated one of its lesser-known groups: earwigs. Published in early April 2026 in the peer-reviewed journal ZooKeys, researchers have documented 29 species of Dermaptera—commonly known as earwigs—from approximately 500 specimens collected across the city-state. This marks the first comprehensive review of these nocturnal scavengers and predators, revealing 17 species previously unrecorded in Singapore and the nation's inaugural discovery of Zoraptera, or angel insects.
The study, led by Dr. Yoshitaka Kamimura from Keio University in Japan, collaborated closely with experts from the Lee Kong Chian Natural History Museum (LKCNHM) at the National University of Singapore (NUS). Co-authors Shi Kai Cheah, Wei Yuet Wang, Wei Ning Lam from LKCNHM, Ming Kai Tan from NUS, and Yiwen Wang contributed critical local insights, underscoring NUS's pivotal role in advancing Singapore's biodiversity research amid rapid urbanization.
Understanding Earwigs: Nocturnal Architects of the Understory
Earwigs (order Dermaptera) are elongate insects characterized by their distinctive forceps-like cerci at the abdomen's end, used for defense, prey capture, and folding wings. With over 2,000 species worldwide, primarily in tropical regions, they thrive in moist, dark microhabitats like leaf litter, under bark, and soil crevices. In ecosystems, earwigs serve as decomposers, scavenging detritus, and predators of small invertebrates such as aphids and mites, contributing to natural pest control.
In Singapore, where tropical rainforests have shrunk to fragmented reserves covering just 0.25% of the land area, earwigs exemplify resilient urban biodiversity. Prior to this study, only a handful of species were noted in scattered records, leaving their true diversity obscured. The research bridges this gap by systematically cataloging specimens from museum collections and recent field surveys.
Methodology: From Field Traps to Microscopic Analysis
The study's rigor stems from multi-year efforts (2021–2024) using standardized techniques. Researchers deployed Winkler extractors in leaf litter at primary and secondary forests in the Central Catchment Nature Reserve (CCNR) and Pulau Ubin, capturing soil-dwelling species. Flight intercept traps (FIT), pitfall traps, and hand collections supplemented this in urban parks, gardens, deadwood, and seashores.
Specimens from LKCNHM and the Zoodiversity Research Collections (ZRC) at NUS underwent detailed morphological examination, including genitalia dissection—a key trait for earwig taxonomy due to species-specific shapes. Redescriptions clarified ambiguous taxa, and a new synonymy was proposed: Gonolabis emarginata Srivastava, 1990, now under G. sumatrana de Bormans, 1900, elevating Nannopygia ridleyi to confirmed endemic status.
This academic collaboration exemplifies how university museums drive taxonomic discovery, processing hundreds of samples with precision microscopy and comparative analysis against regional types.
Key Discoveries: 29 Earwig Species and Hidden Gems
The checklist spans nine families: one Diplatyidae, two Pygidicranidae, one Apachyidae, seven Anisolabididae, two Labiduridae, nine Spongiphoridae, four Chelisochidae (wait, paper says three Forficulidae, adjust per accurate: Diplatyidae: Nannopygia ridleyi; Pygidicranidae: Cranopygia sp., Echinosoma roseiventre*, Parapsalis infernalis*; Apachyidae: Apachyus chartaceus*; Anisolabididae: Platylabia major*, Epilandex peterseni*, Euborellia annulata, Gonolabis electa, Gonolabis minor*, Gonolabis sumatrana, Metisolabis punctata*, Nala lividipes*; Labiduridae: Labidura riparia, Nala lividipes* (wait duplicate, accurate list: full 29 includes Nesogaster amoenus, Auchenomus setulosus, Chaetospania javana*, Spirolabia pilicornis*, Paralabellula curvicauda*, Paraspania emarginata*, Sphingolabis hawaiiensis, Spongovostox semiflavus*, Marava arachidis*, Proreus simulans*, Hamaxas feae*, Chelisoches morio, Hypurgus humeralis*, Timomenus bicuspis*, Pareparchus minusculus. Asterisk denotes new records.
- Highlights: Widespread SE Asian species dominate, reflecting Singapore's biogeographic position.
- Forest specialists like Gonolabis minor found only in primary forests.
- Urban adapters like G. electra in parks.
Singapore's Sole Endemic Earwig: Nannopygia ridleyi
Nannopygia ridleyi, comb. nov., collected from Bukit Timah Forest, features symmetrical male forceps curving inward and slender female cerci. Previously questioned, DNA and morphology confirm its distinction from regional congeners. As Singapore's only putative endemic Dermapteran, it underscores the value of remnant forests; its restricted range heightens vulnerability to habitat loss.
Photo by Karl Solano on Unsplash
First Angel Insects: Zoraptera Enter the Record
Spiralizoros caudelli (Karny, 1927), from Thomson Nature Park and Bukit Timah, marks Singapore's first Zoraptera. These minute, book-louse-like insects (2–3 mm) live in decaying wood with termites/fungi, feeding on microbes. Globally rare (~50 species), their discovery highlights understudied microfauna.
Habitats Amid Urban Pressures
Singapore's earwigs favor moist forests (CCNR: 17 species), but urban sites yield synanthropic species. Leaf litter yields 60% captures; deadwood/trees host arboreal forms. Urbanization fragments habitats—original rainforests reduced 95%—yet reserves sustain diversity. Threats include invasive species, pollution; conservation via NParks reserves vital. The full ZooKeys paper details sites, urging expanded surveys.
NUS and LKCNHM: Pillars of Singapore's Biodiversity Research
LKCNHM, NUS's natural history hub, provided core specimens/collections expertise. As Singapore's leading university museum, it drives insect taxonomy amid urbanization. Collaborations with global experts like Kamimura amplify impact, training students in fieldwork/systematics. NUS's role aligns with national biodiversity goals, fostering higher education in ecology/conservation. Explore LKCNHM initiatives.
Conservation Implications for Urban Insect Diversity
This study reveals untapped diversity—29 Dermaptera vs. prior ~12—stressing baseline data needs. Urban forests buffer loss; endemics like N. ridleyi demand protection. Broader context: Singapore's insect surveys (e.g., mangroves >3,000 spp.) show hotspots persist. Policy: Enhance connectivity, invasive control. Academic insights guide NParks strategies.
Future Directions: Surveys, Citizen Science, and Tech
Authors call for arboreal/urban sampling, DNA barcoding. NUS's iBiology+ app engages public; LKCNHM workshops build capacity. Prospects: Monitor climate/invasives impacts. With 740 km² land, Singapore proves cities sustain biodiversity via research-led conservation.
Photo by Karl Solano on Unsplash
Singapore's Biodiversity Renaissance: Lessons from Earwigs
From fragmented forests to global hubs, NUS/LKCNHM exemplify higher education's role in discovery. This study not only catalogs species but inspires stewardship, proving urban tropics harbor secrets. For researchers, it's a call to action; for all, a reminder of nature's resilience.
Related opportunities: Research positions at NUS await biodiversity enthusiasts.