Transcript:

Today on Animal Fact Files we’re discussing rhinoceros beetles. These hefty bugs are also known as elephant beetles, hercules beetles, and - our personal favorite - unicorn beetles. For simplicity, we’ll be referring to the subfamily as a whole as rhinoceros beetles. These beetles get their name from the conspicuous horns present in the adult males of some species. Not all rhinoceros beetles have this fancy headgear, though. There are two ways in which rhinoceros beetles complete their life cycle. For the groups that have those splendid horns, eggs are typically laid in the late summer and the larvae overwinter until they pupate in the spring. The adults emerge in the early summer. The males are often seen but the females are generally sedentary and draw males to them via pheromones. These adults may have very small or even no mouth parts. They’ll breed and perish with the onset of cold weather. There are, however, groups of rhinoceros beetles without the ornamented males and these have a slightly different life cycle. Their eggs are laid in the early summer and the larvae develop quickly. The adults may emerge in autumn or remain in the pupal stage until the following spring. These adults have functional mouthparts and the females are active; they’re collected as commonly as the males. All rhinoceros beetle adults, however, tend to be nocturnal, and they are present in nearly all terrestrial habitats around the world with the exception of polar regions.

Most of the eating during a rhinoceros beetle’s life cycle happens during the larval stage. Rhinoceros beetle eggs are usually laid in rotting vegetation including dead trees so that they have plenty of food when they hatch. Rhinoceros beetle larvae eat roots, stems, decaying logs and organic matter. In fact, the larvae can sometimes be larger than the adults such as the case with the hercules beetle. Of course, they can’t all be chonky like Chester. Some rhinoceros beetles only reach about 4mm (0.15 inches) in length while others can reach more than 6 inches (150mm)! This also means they can make a nice meal for other animals.

Adult rhinoceros beetles have some ways to deter predators. For example the males with horns may use these in self defense. Rhinoceros beetles are also able to produce hissing or squeaking sounds by rubbing their abdomen against their wing covers. Larvae, however, may more easily fall prey to predators including birds, bats, rats, and more. Male rhinoceros beetles also have to watch out for each other. The horned individuals use their pronotal projections to grab one another and either try to slam their opponent to the ground or push them off a perch - not unlike the stag beetles we’ve talked about previously. Rhinoceros beetle adults are usually found crawling along the ground, but those who take to the tree may attempt to push each other off in order to win favor over females.

Rhinoceros beetles are scarabs, like dung beetles, and while many appear black in color, some, like the hercules beetle, are able to change color based on the moisture in the environment. Higher levels of humidity makes them black, but lower humidity turns them green! In the wild, the largest rhinoceros beetles may live to be up to three years old, though most only live about a year from egg to adult.

For more facts on rhinoceros beetles, check out the links in the description. Thank you to Akanio for today’s request! Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files!