The large blue — a butterfly so rare that it was briefly extinct in Great Britain. As populations of the large blue dwindled throughout the 20th century, scientists struggled to determine a cause. In order to reach adulthood, large blue butterflies require help from a specific species of red ant. After several months, the caterpillars pupate and then emerge from the ant nests as large blue butterflies. This account was rejected by the court, and he was found guilty of capturing, killing, and possessing two large blue butterflies.