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Every year, researchers discover dozens of animal species, adding to the millions that exist on our planet. One group, in particular, contains an extremely large portion of the Earth’s biodiversity. So, of all the groups of animals on our planet, which one has the most species?
According to estimates of Camilo Mora, associate professor in the Department of Geography and Environment at the University of Hawaii at Mānoa, insects are the most diverse animal group. His research predicts that there are no less than 3 million species of insects, which means approximately half of all animal species There are insects on Earth.
One type is particularly prolific. “Of the insects, the group that has the most species are the beetles: there are almost 400,000 species of beetles,” he said Jessica Ware, evolutionary biologist and associate curator of invertebrate zoology at the American Museum of Natural History in New York City. In fact, that means 1 in 3 The animal species is a beetle, making them the most species-rich creatures known on Earth. For comparison, while there are almost 3,000 species of snakes, “there are twice as many (just) ladybug beetles!” Ware told LiveScience.
Why have beetles and the broader class of insects been so successful? There are many possible reasons. One possibility is that insects have been around for almost 500 million years, making them one of the oldest groups of animals. That has given “time for speciation to occur, for species to accumulate,” Ware said. Most insects also have short lifespans, which typically coincides with faster reproduction rates and more offspring, creating more opportunities for mutations leading to new species, Mora explained.
High levels of speciation have also given insects more opportunities to adapt and thrive in thousands of ecological niches around the world. For example, beetles’ outer wings not only allow them to fly but also serve as a protective covering that allows them to burrow underground, Ware said.
Related: Do bees really die if they sting you?
“The other possibility is that perhaps there are other equally diverse groups (such as insects), but we have not studied them,” Mora said. In fact, in a study 2018Researchers proposed that a group of insects known as parasitoid wasps may contain even more species than beetles, but we’ve spent less time studying them.
Although the variety of insect species far eclipses that of fish, amphibians, reptiles, birds, and mammals, all of these groups contain impressive numbers.
Mammals’ 5,500 species It might seem pitiful compared to the 3 million insects. But more than a quarter of mammals are rodents: 1,500 species, including rats, squirrels, beavers, capybaras and porcupines. Of the more than 8,000 species of amphibians described, a surprising 90% They are frogs that, together with toads, form 7,000 species. Reptiles boast of being somewhere in between 10,000 and 12,000 species, the most of which belong to the order Squamata, comprising mainly lizards, of which there are approximately 5,500 to 7,000 species. Not to be outdone, an order of birds, called passerines or perching birds, represents 5,300 species, the same number of mammal species as on Earth. The most diverse of this gigantic order is a family known as tyrant flycatcherwith an estimate 400 species. Together, passerines make up more than half of the 10,000 known bird species living on Earth today.
And experts believe there are as many as 34,000 fish species: more than all other vertebrate species combined. With more than 3,000 Of these, the order Cyprinids, which contains freshwater fish such as minnows and carp, is the most diverse.
Still, none of them come close to the magnitude of the beetles and their insect family. There is 1.4 billion individual insects for every human being on Earth, and their combined weight exceeds that of humanity by 70 times. And while they may seem like a nuisance or dangerous disease vectors, insects are crucial to life on Earth: they provide pollination and increase soil nutrients that support our food systems, clean our fresh water and are a source of food for thousands of species.
This makes it even more worrying that Insect populations are in decline.. Without them, Ware said, “what we predict is a world that would not support life as we know it, not just our human life, but animal diversity and plant diversity.” They may be small, Mora said, but “humanity stands on the shoulders of insects.”
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