Butterfly crisis: US populations plummet by 20% since 2000

In the United States, no other insects are studied as thoroughly as butterflies. The latest findings, published in "Science", reveal that American butterflies are disappearing rapidly due to factors such as climate change, habitat loss, and competition from more resilient insects. Over the past 25 years, the butterfly population has decreased by as much as 22%.

The largest declines in butterfly numbers have been recorded in Arizona, New Mexico, Texas, and Oklahoma, where the number of insects has more than halved since 2000. "And we don't see any sign that that's going to end," said Nick Haddad, an entomologist at Michigan State University and co-author of the study published in the scientific journal.

Across the country, as many as 114 species exhibit a drastic decline in numbers, while the population of only nine species of these beautiful insects is growing. For example, in 1997, there were approximately 1.2 million monarch butterflies (Danaus plexippus) in the USA, but now there are fewer than 10,000. This species may therefore be added to the endangered list.

David Wagner from the University of Connecticut notes that while the annual population decline may seem small, in the long term it is catastrophic.

Eliza Grames, an assistant professor of biological sciences at Binghamton University, emphasises that butterflies are not only "an ambassador for nature's beauty" or a source of inspiration for artists and photographers, but above all an important element of the ecosystem, crucial to humans as well. Butterflies play a vital role in assisting with the pollination of plants, which are essential for food production. They also contribute to maintaining the balance of ecosystems around the world.

Researchers can now draw conclusions from the latest studies and work towards reducing the decline in butterfly populations.