One morning while walking around the tear-drop circle drive at the entrance of the Museum, I stumbled upon a very large insect. As I got closer, it got LARGER. Then I noticed it had a horn. When I got right up on it, I realized it was what they call an Eastern Hercules beetle (Dynastes tityus). The Hercules beetle is one of the largest beetles in the United States. It spends the majority of its adult life foraging the forest floor in search of food. These beetles will only eat decayed plant material, wood, and fruits. The Hercules beetle is said to be the strongest creature on the earth for its size, able to carry 850 times its body weight. But it is still hunted by numerous animals such as bats, rats, birds, and other carnivores.
Discerning a male from a female is very simple: the male has the horn on the front part of the head, while females do not, but they may have a larger body. Both male and female are colored the same: green-gray body with sporadic black spotting. The length of the horn on the male is determined by how much nutrition was consumed during the larvae stage.
When I started researching this massive insect that resides in our forests at Crystal Bridges, I was impressed by the length of time it took to become an adult, as you see in the photos. Adult beetles emerge in the spring. When fully emerged, the female beetle immediately releases pheromones to attract males. After mating, the female will lay up to 40 eggs across a 30-day period in the warmer months. Most eggs will be laid in the ground under old logs or even in the older fallen tree. In one month the egg hatches into larvae, and the larvae will consume the rotten wood around it for food, or if laid in the ground, the larvae will burrow up to the log and begin to feed. The Hercules larvae will remain in the log for 12 to 18 months feeding, molting, and growing into the next life stage, which would be a pupae or cocoon. It will remain in the pupae for an additional 2 to 3 months, or even longer depending on the condition of the weather. Some larger pupae will overwinter, leading to a two-year life span. After emerging as an adult, typically the beetle will only live for 3 to 6 months.
You may be able to spot adult beetles on trees such as Eastern white pine, red silver maples, white oak, and other plant material like Virginia creeper, Japanese honeysuckle, and spice bush. Beetle numbers are decreasing from de-forestation and sightings are becoming rare. Here at Crystal Bridges we have the perfect habitat for the Hercules beetle because of our native plants and trees that provide food and shelter.
Although this insect looks very intimidating, it is harmless to humans. So when or if you spot one on the grounds, just remember how long it took to be a part of our ecosystem and how short-lived the actual adult life is. Admire it, and let it go on its way.