The Eastern Hercules Beetle (Dynastes tityus) is one of the largest beetle species in North America, known for the impressive horns on the males. Understanding their diet is complex because it shifts dramatically between their two main life stages: the larva and the adult.
Diet of the Larval Stage
The life of the Eastern Hercules Beetle begins as a larva, a large, C-shaped grub that acts as a decomposer within the forest ecosystem. This larval stage is the longest of the beetle’s life cycle, often lasting between 12 and 18 months, or even up to two years. The larva is a detritivore, meaning its entire diet is composed of dead and decaying organic matter, primarily rotting wood and leaf litter.
The grubs consume massive quantities of decaying hardwood, such as oak, willow, black locust, or wild cherry, to fuel their significant growth. This feeding process is termed saproxylophagous, indicating a diet of dead wood. By consuming this material, the larvae play a crucial role in nutrient recycling, breaking down tough plant fibers and returning organic matter back into the soil. The quality and quantity of this food determine the final size of the adult beetle, including the length of the male’s distinctive horns.
Diet of the Adult Stage
Once the beetle emerges as an adult, its feeding habits change to focus on energy and hydration for reproduction. The adult stage is relatively short, typically lasting three to six months. The primary natural food source for the adult Eastern Hercules Beetle is tree sap, which they seek out on specific hardwood species like ash trees.
The beetles access this sweet liquid by using their mouthparts to scrape at the bark, or more commonly, by feeding at existing wounds or scars on the tree. They are also attracted to soft, sweet, and often rotting fruits found on the forest floor. Overripe fruits like bananas, apples, and oranges provide the necessary sugars for energy during this reproductive period. Notably, the male’s large horns are used for battling other males for mates and territory, not for acquiring food.
Feeding Hercules Beetles in Captivity
Larvae must be provided with a substrate that serves as both their housing and their food supply. This is typically a specialized mix called “flake soil,” which is finely ground, fermented, and decayed hardwood. The substrate must be kept moist, but not saturated, and should be replaced or refreshed every one to two months as the grubs consume it.
For adults, the diet is much simpler and focuses on high-sugar foods to maintain their energy. Commercial beetle jelly is a convenient option that provides balanced nutrition and is easy to maintain. Soft, overripe fruits like banana, melon, or apple slices are also readily accepted. Any uneaten portions of fresh fruit must be removed daily to prevent mold and bacterial growth in the enclosure.