There are many different varieties of rhinoceros beetle, and almost all of the males have one large horn on their head, one on their thorax and two smaller horns next to the thorax horn. It is these horns that give it its name. The name Hercules beetle is sometimes used because this particular insect is the strongest land animal on the planet relative to its size. It can lift up to 850 times its own weight. The different types of rhinoceros beetles have different life cycles and varying lifespans, but the more common eastern Hercules beetle goes through a complete metamorphosis from egg to larvae to pupae to adult with a life span of about two to three years.
When the female rhinoceros beetle emerges from her pupal stage she begins to emit pheromones which attract the males to her. When more than one male suitor arrives they will battle each other, using their horns, to try to win the female. The males can inflict a lot of damage upon each other with their horns and can sometimes kill their opponent. Other times the weaker male will simply retreat to allow the stronger beetle to mate with the female.
The female Hercules beetle is relatively dull to look at compared to the male, and even though she has no horns she still manages to burrow her way under the soil to lay her eggs. The eggs are very large for insect eggs, measuring up to half a centimetre in length and are white in colour. The female buries them to incubate them and to try to protect them from predators.
After approximately one month the eggs will hatch into larvae that will remain underground for six months to a year. While they stay buried they feed and grow, sometimes reaching four inches in length. Over the course of this time the larvae will shed their skins twice before entering the pupal stage.
The eastern Hercules beetle will only spend a short amount of time in this stage before it emerges as an adult. The larvae will make a pupae cell in dead wood or the soil where it feeds and it will stay there without feeding for a few weeks before it is ready to break free and begin feeding as an adult.
When the adult first leaves the pupae cell its normally hard exoskeleton is soft, vulnerable and pale in colour. It takes a few hours for this to harden and give the adult its full protection. Regardless of when it leaves the pupal stage, the adult rhinoceros beetle won't leave the safety of the underground until spring. It is most active in the warmer months and will use this time to find new feeding grounds and new females to mate with.