Insect Species in the World May Be Three Times More Than Thought

It is estimated that at any given moment in the world, there are approximately 10 quintillion living insects, and this number constitutes the largest biological mass of all land animals. According to data from the Smithsonian Enstitüsü, mosquitoes, bees, and butterflies that invade our gardens during the summer months represent only a very small fraction of this gigantic ecosystem. For a long time, scientists believed there were about six million insect species in the world, using this figure as a generally accepted consensus. However, a striking new study published in the Proceedings of the National Academy of Sciences reveals that this traditional head count contains a major flaw. According to the study, the true number of insect species on Earth ranges between 14 and 20 million, meaning it can be almost three times the current estimates.

This extraordinary increase in species has created both excitement and concern in the scientific world, because global biodiversity is under threat. Factors such as climate change, agricultural expansion, and rapid habitat loss are causing alarming declines in the populations of vital pollinators like bees and monarch butterflies. Environmental pollution and deforestation are shrinking the habitats of these tiny creatures that form the foundation of the food chain, causing many species to go extinct without us even realizing it. Entomologist Laura Melissa Guzman, a co-author of the study from Cornell Üniversitesi, draws attention to the risk that undiscovered and unnamed species could silently enter the extinction process. For this reason, understanding the true diversity of species is not only an entomological curiosity but also an urgent necessity for global conservation efforts.

To carry out this massive count, researchers focused on the Guanacaste (ACG) region in Kosta Rika, a 418.000-acre nature reserve stretching from the Büyük Okyanus to the Karayip Havzası. Scientists chose to study a group of small, parasitic wasps called "Microgastrinae" in this highly diverse region. Microgastrinae wasps are among nature's terrifying but fascinating species, known to lay their eggs inside unfortunate caterpillars to reproduce, where the hatched larvae develop by consuming the host's internal organs. The main reason researchers selected this group is that this family is already well-sampled and the majority of its species have been cataloged. Thus, this specific population was deemed suitable to be used as a scientific reference point or benchmark to estimate the total number of insect species in the entire region.

The science team set up Malaise traps in the area, which are curtain-like traps that cause insects flying by to crash and fall into an ethanol bottle, thereby ensuring the samples are perfectly preserved. Through a primary and two secondary trap arrays, a total of over 1,6 million insect samples were collected and transported to the laboratory. In the laboratory, a portion of each insect's genome was sequenced through a robotic and high-speed system, creating a species-specific barcode. As a result of this process, it was determined that the 1,6 million insects collected represented 54.000 different species. Although these numbers seem incredibly large, they still represent an incomplete data set considering the massive size of the region and the limited locations of the traps.

To address the incomplete sampling and calculate the total number of species in the conservation area, researchers used a statistical subsampling model that compared the trapped insects with those flying freely in the forest. This estimation model projected that there are 2.400 Microgastrinae species and, alongside this, a staggering total of 333.000 insect species just in the Guanacaste region. This dense biodiversity in the Guanacaste region was used as a stepping stone to estimate global insect species; reaching a new global estimate of 20 million through calculations based on the global distribution of other groups of organisms such as mammals, amphibians, and trees. As humans, as we continue to destroy these habitats as a single species against millions of insect species, it is clear that time is rapidly running out to protect and document this undiscovered wealth.