An analysis of recent discoveries indicates that the scientific community has significantly underestimated the biodiversity of terrestrial ecosystems. Current estimates suggest that only about 5% of all terrestrial insect species have been studied to date.

The Scale of Insect Diversity

Insects are the most numerous group among land animals. For example, the global population of ants exceeds 20 trillion individuals, although their total biomass is about 12 million tons—much less than the biomass of humans (390 million tons). For entomologists, not only absolute numbers matter, but also species diversity. However, more than 90%, and by some estimates over 95%, of all insect species inhabit tropical and equatorial forests. These regions are remote from most specialists, and finding small insects in such environments is extremely challenging.

Estimating Unknown Species

The question of how many insect species remain undiscovered is complex. It is generally believed that for every known million species, there are about five more that have yet to be identified.

Genetic Analysis and New Estimates

In a recent study, genetic data from 1.6 million specimens of tropical insects were used to assess overall genetic diversity. The sample included representatives of 54,000 species, with an average of 30 individuals per species. All samples were collected using thirty standard traps in the Guanacaste reserve in Costa Rica, covering dry, mountainous, and wet tropical forests. Despite its small territory, Costa Rica surpasses high-latitude countries in biodiversity thanks to its warm climate.

Statistical Methods and Results

Using various statistical methods, researchers calculated that the reserve contains about 330,000 unrecorded insect species, which is a third of the number of known species. Thus, just 30 traps allowed scientists to detect roughly every fifth species. Based on these data, even the most conservative estimates suggest there are at least 14 million insect species on Earth. More realistic estimates exceed 20 million, and the most optimistic ones approach 30 million.

The Significance of These Findings

Despite the wide range of estimates, the results indicate that insect species diversity is at least an order of magnitude greater than that of all other terrestrial animals. At the same time, the proportion of discovered insect species likely does not exceed 5% of their total number.