Before 1945, Hawaiʻi released wasps to kill crop pests; decades later, they made up 83% of the parasitoids found attacking native forest moths

For much of the 20th century, Hawaiʻi relied on imported insects to deal with agricultural pests. Parasitic wasps were brought in because they attacked crop-eating caterpillars before the insects could do much damage. At the time, biological control offered farmers another way to deal with pests. Some of those wasps, however, did not stay in agricultural areas. They eventually reached native forests, where they encountered moth species they had never been introduced to control. A study published in Science