Some stick insects have reproduced without sex for around one million years, yet they still carry a fully functioning genetic system associated with sexual reproduction, according to surprising new research. The research, led by Dr. Darren Parker, a lecturer in evolutionary biology at Bangor University, examined several species of Timema stick insects. Timema are small, wingless stick insects native to the western United States. In sexually reproducing animals with sex chromosomes, males and females can have different numbers of X chromosomes. For these unusual stick insects, a million years without sex apparently has not been enough to erase an old piece of their evolutionary past.