A new study estimates there could be 14 to 20 million living insect species globally, nearly three times higher than the previously accepted figure.

The estimate hinges on intensive sampling in Costa Rica’s Guanacaste region, where Malaise traps and caterpillar rearing helped catalog a large portion of the local wasp diversity, especially Microgastrinae.

Statistical models reveal many species are small, rare, and highly specialized, with 75% of captured wasp species found using only one of three sampling methods, underscoring underdetection.

The work presents a baseline implying many undiscovered species could be common, and many may be vulnerable to pesticides, climate change, habitat destruction, and light pollution.

The findings, published in PNAS on June 29, 2026, stress that current knowledge underestimates insect diversity and call for intensified taxonomic work and long-term biodiversity monitoring.

The study arrives amid concerns about an insect decline or 'Insect Apocalypse,' highlighting the urgency of cataloging biodiversity before species are lost.

Authors warn that numerous species are already declining even before being named, emphasizing urgency in understanding and protecting biodiversity.

Taxonomic knowledge must keep pace with biodiversity loss as habitat destruction and climate change threaten species yet to be cataloged.

Many undiscovered species may occupy niche or canopy habitats and could play critical roles as parasitoids within broader food webs.

The figure is a lower bound, underscoring the importance of cataloging insect diversity to monitor declines and conservation needs amid climate and land-use changes.

The study reinforces the idea that a larger pool of undescribed insects may be at risk, reinforcing the case for conservation.

A Costa Rican dataset with over 1.5 million specimens across multiple trapping methods underpinned the robust estimation workflow and global extrapolation.