The new estimate gives a clearer dimension to the unknown world of insects — and what may disappear before it is even identified by science.
A new estimate of insect diversity, calculated in a published this Monday in PNASsuggests that there are at least 14 million to 20 million species buzzing and crawling around the planet.
The value is two to three times higher to that of others, which put the count at around 6 million species, researchers report in a study published June 29 in the journal Proceedings of the National Academy of Sciences. So far, only about 1 million insect species have been officially named and described.
Many insects are facing a ““. Populations are declining for numerous reasons, including pesticides, climate changehabitat destruction and light pollution.
The new value helps define a rough benchmark for the number of insect species that exist on Earth, including many still to be discovered which, like those already known, may also be at risk.
“It helps us understand how much we could be losing”, says the entomologist Laura Melissa Guzmanbiodiversity researcher at Cornell University and co-author of the study, cited by . “And it shows that we have to continue studying these insects to better protect them.”
Guzman and colleagues analyzed the DNA of more than 1.6 million insects belonging to approximately 54,000 speciescaptured in traps installed in the Area de Conservación Guanacaste, a protected zone listed as a World Heritage Site in northwestern Costa Rica.
The region is a good starting point because it is well studied, says Guzman. For more than 40 years, researchers have used traps and other methods to monitor insects in the region’s dry forest, rainforest and cloud forest ecosystems, from coastal to mountainous areas.
The team focused on one subset of these insects: parasitoid vespas of the subfamily Microgastrinae. In one of the subsets analyzed, researchers examined more than 11,000 specimens, distributed across 388 species.
Compared to charismatic and much-studied groups such as beetles, parasitoid wasps are very diverse, but remain little studiedknee Guzman.
This survey of the wasps allowed the team to resort to statistical methodss to calculate how many species could have gone unnoticed, even in a large sample of more than 1 million insects.
The team concluded that about 2,400 species of parasitoid vesps will be able to live in the Guanacaste Conservation Area, as well as more than 300,000 others insect species.
From then on, researchers extrapolated the values to determine what could exist on a global scale.
Even the lowest estimate of 14 million speciessuggests that there are millions of insects yet to be discovered. “It’s humbling to realize how much we don’t know,” says Guzman. “And how much we still need to know.”
