Source: Flinders University
26 August 2026
While extreme weather and habitat changes can spell doom for many native animals, including insects, a different picture has emerged from a new study led by Flinders University.
Long-running investigations into native bee populations of Fiji bees indicate several species of the lowland ‘sweat bees’ (genus Lasioglossum), have evolved and used their individual traits to resist human-driven environmental changes to survive and thrive.
“Our research suggests that all populations of the Fijian bees we sampled on the main island of Viti Levu have undergone recent population expansions, independent of climate change trends across the Pacific region,” says PhD researcher Patricia Slattery, from the Behaviour and Ecology of Terrestrial Anthropods (BETA) Lab at Flinders.
“These are consistent with other studies finding that forest clearing and introduced plant species – including invasive plants – can actually increase nesting opportunities for Fijian bees, especially at lower elevation,” says Ms Slattery, the first author of the new study published in the high-profile Journal of Biogeography.
“This contrasts with other evidence that human occupation of Fiji has led to decreased biodiversity, including in some ant and other bees, while raising the possibility that human-mediated (‘anthropogenic’) environmental changes can actually benefit some native tropical insect groups.”
These surprising results come at a time when endemic, montane (mountain slope dwelling) tropical insects are recognised as some of the most vulnerable animals, and population declines have been recorded in many parts of the world.
This study found that since the first human settlement of Fiji about 3000 years ago, these ground-nesting bees have capitalised on some new ecological opportunities created by land clearing and exotic flowering plants. While more isolated highland species on Fiji’s main island showed relatively stable numbers, lowland species had a strong recent upward trajectory.
However, researchers emphasise the study highlights an exception to the global trend of major losses of vital native pollinators in the face of environmental disruptions.
Co-author Dr Mike Schwarz says it appears the life history of these lowland native bees, in contrast to the forest-specialist masked bees, for example, has allowed them to adapt much better to human-induced changes.
“It is interesting to see how signals from ancient human arrivals have left their mark on the genetics of Fijian native bees,” he adds.
The study recorded the remarkable recent radiation in five species of native Fijian bees in the subgenus Lasioglossum (Homalictus) – L. fijiense, L. tuiwawae, L. groomi, L. ostridorsum and species S.
The research – ‘Anthropogenic effects, not climatic factors, are correlated with Holocene population expansion of an insular bee fauna’ (2026) by Patricia S Slattery, James B Dorey, Bruno Alves Buzatto, Mark I Stevens, Michael SY Lee and Michael P Schwarz – has been published in the Journal of Biogeography. DOI: 10.1111/jbi.70341.
Acknowledgements: This work was supported by Australian Government’s New Colombo Plan (NCPST Fiji 15482), the Australian Government Research Training Program, Playford Trust, and AJ and IM Naylon PhD scholarships. The authors would like to thank the Meli and Navai villages, and Marika Tuiwawa for their invaluable assistance in specimen collection and Fijian field logistics which were carried out under permit number 1755-11.