All living organisms go through stages of growth and reproduction. The emperor moth does its growing and reproducing in remarkable ways. The egg hatches into a caterpillar in the summer in southern Africa, developing into a strong worm, hungry for a share of leaves to grow over the following weeks. Once the caterpillar has eaten its fill, it makes its way down the tree to dig itself into the ground and pupate, and then wait until good rains fall sometime during the years ahead.
Once rains have wetted and cooled the soil, a beautiful adult moth emerges from each pupal cocoon. Adults only live for 3-4 days. Their sole purpose is to reproduce; they do not even have a mouth to feed! To make the most of this short window of opportunity, female moths release pheromones from glands at the tip of their abdomens to attract males. Males are equipped with large furry antennas designed for detecting tiny traces of female pheromones in the air, sometimes over distances of several kilometres.
Left: Female Emperor moth (G Maya), take note of the smooth antenna; Right: Male Emperor moth (G Maya), take note of the furry antenna.
During summer 2021, I collected several emperor moth pupae and kept them in a bed of sand in anticipation of the next summer. To my surprise, only females emerged from pupae. I then placed one of them in a large wooden box covered by a net so that the pheromones could be released freely in the air. The next morning an astonishing number of nine males were hanging around the female waiting for the opportunity to be selected as her mate to produce the next generation of emperor moths. So many males for a single female makes one wonder if she was the only Empress mopane moth in the bush that night...