From pollination to decomposition and nutrient cycling, insects are indispensable to maintaining a healthy ecosystem. But recent reports of declining insect populations have raised fears of an "insect apocalypse."
A team at the Okinawa Institute of Science and Technology Graduate University (OIST) in Japan released on the 12th the results of tracking changes in insect diversity through genome analysis of ants in Fiji. The findings were published the same day in the international journal Science.
Evan Economo, a professor at OIST and the University of Maryland, said, "With a few exceptions, we have not directly monitored insect populations over time, so it can be difficult to infer historical changes in insect numbers," adding, "We chose a new approach that simultaneously analyzes the genomes of multiple species from recently collected museum specimens."
The team decoded DNA from museum-held specimens to reconstruct the ants' evolutionary relationships, pathways of arrival to the islands, and population changes. Using a method known as "museumomics," they analyzed and compared the genome sequences of thousands of ants.
As a result, 79% of native ant species that live only in Fiji were found to be in decline. In contrast, nonnative ants that recently arrived through human activities increased sharply in number. The decline in native ants was particularly pronounced over the centuries marked by the arrival of Europeans and colonization, the expansion of global trade, and the advent of modern agriculture.
These changes align with the characteristics of islands as closed and vulnerable ecosystems. Native ant species are less adaptable to external changes, making them highly susceptible to introduced species and environmental disturbances. Researcher Cong Liu said, "Islands with closed and isolated ecosystems feel human impacts more quickly. It is like the canary in the coal mine."
In fact, many historical extinctions have occurred on islands. Analyzing the genomes of about 100 ant species, the team identified 65 island colonization events, ranging from natural arrivals millions of years ago to recent transfers via human trade.
The researchers said, "This study will help continually build scientific understanding of insect populations and support conservation efforts," noting, "In Okinawa as well, we are conducting acoustic monitoring and trapping to measure the biological diversity of insect populations in real time."
Alexander Mikheyev of Australian National University, who led the study, said, "This research underscores the importance of biodiversity and museum collections," adding, "As our scientific tools expand, the amount of information we can extract from collections is growing. Continued investment in and maintenance of this resource are therefore essential."
References
Science(2025), DOI: https://doi.org/10.1126/science.ads3004