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40 Interesting Facts About Hercules Beetles (Genus Dynastes)

Linda Crampton is a writer and former science teacher with an honors degree in biology. She enjoys writing about science and nature.

Impressive Insects

Hercules beetles are large and impressive insects. They are known for the long horns of the male, which act as pincers, and their ability to change colour. The insects are named after Hercules, the hero of Ancient Greek and Roman mythology who was famous for his tremendous strength. The beetles are often attractive animals and have some interesting features and behaviour.

This article describes forty facts about the Hercules beetle that lives in tropical parts of the world and about the western and eastern Hercules beetles that live in the United States. The three insects belong to the genus Dynastes and the family Scarabaeidae. The members of the family are often called scarab beetles. One member of the family with the scientific name Scarabaeus sacer was sacred to the Ancient Egyptians.

The Hercules beetle has the scientific name Dynastes hercules. The insect is found in Central and South America and the West Indies. It belongs to the family Scarabaeidae and the subfamily Dynastinae. The members of this subfamily are known as rhinoceros beetles.

External Anatomy of the Hercules Beetle

1. As in other insects, the body of a beetle is divided into three sections: the head, the thorax, and the abdomen. Also as in other insects, a beetle has three pairs of legs, which are attached to the thorax.

2. Beetles have two pairs of wings. Like the legs, they are attached to the thorax, but when they're folded they extend over the abdomen. The forewings are known as the elytra. They are hardened and serve to protect the delicate hindwings, which are hidden underneath and are used for flight. The elytra are moved out of the way when a beetle takes to the air.

3. The male Hercules beetle is black in colour, sometimes with the exception of the elytra. In a dry atmosphere, the elytra are yellow to olive green and are decorated with dark spots and fine streaks. When the atmosphere is humid, the elytra become completely black.

4. Females may be entirely black in a dry atmosphere but sometimes have elytra that are partially coloured. The colour possibilities are the same as those found in the males. As in the male, the colour fades in a humid environment. Females sometimes have a weaker ability to change colour than males, however.

5. The male has two extensions at the front of his head, which are known as horns. The length of the horns varies, but the upper one is generally much longer than the lower one.

6. Beetles have compound eyes (ones that contain multiple visual units) and chewing mouth parts. The eyes of a Hercules beetle are located on the sides of the head slightly below the lower horn.

The cuticle is the outer covering of an insect's body. Researchers say that the colour of a dry Hercules beetle depends on the structure of the cuticle in the elytra. When the cuticle contains water, its structure changes in a specific way and its ability to create colour disappears.

Facts About the Horns

7. The upper horn of the beetle is called the thoracic horn, since it begins at the thorax. The lower one is known as the cephalic horn because it begins at the head. ("Cephalic" means of or relating to the head.)

8. Adults Hercules beetles are around two to three inches in length, not including the horn. The male may be as long as seven inches if his thoracic horn is included in the measurement. The insect is listed as the longest insect in the world with respect to total length by Guinness World Records. The titan beetle of South America has the longest body length, however.

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9. The length of the horns depends on a variety of factors, including genetics, nutrition, and environment. The thoracic horn is usually considerably longer than the cephalic one.

10. The males use their horns for fighting with each other prior to mating with a female. The winner gains the right to mate.

11. The conflicts are sometimes only indirectly related to mating. The male maintains a territory during the mating season and fights to protect it from other males.

12. A male tries to grasp his adversary between his horns so that he can lift him into the air and then throw him to the ground. The fight continues until one of the beetles is injured, retreats, or is left upside down and helpless.

Habitat, Diet, and Behaviour

13. The Hercules beetle inhabits lowland and mountain rainforests.

14. The larvae live in wood from fallen trees. They feed on rotting wood and other decaying plant material.

15. The adult beetles are generally nocturnal or crepuscular (active at twilight). They can fly, but they usually stay on the ground, where they forage for food.

16. During the day, the adults hide in leaf litter. At night, they feed on fruits that have fallen to the ground.

17. The beetles are solitary animals except when a male and female meet to mate or when one male meets and confronts another one.

18. Observers say that the beetle creates a huffing sound by rapidly vibrating its abdomen against its elytra. This sound may act as a warning to predators.

Life Cycle of the Insects

19. The beetle exhibits complete metamorphosis. The developing insect goes through four stages, each of which looks different from the one before. The first stage is the egg. This is followed by the larva, or grub, and then the pupa. The pupa becomes an adult.

20. Many details of the beetle's reproduction have been discovered by observing captive animals. The insects are sometimes kept as pets. The reported time for each stage varies considerably and may depend on environmental conditions, such as temperature

21. The female lays up to a hundred eggs in the ground or inside wood lying on the ground. She leaves the eggs unattended.

22. The eggs hatch in around twenty-eight to thirty days. Three larval stages, or instars, follow. The beetle remains in a larval stage for twelve to eighteen months.

23. The last larval stage eventually becomes a pupa. In this stage, the developing insect is covered by a hard case made of soil and its own feces.

24. After one to three months, an adult beetle emerges from the pupal case. The adult may live for three to twelve months longer. The reported time period is highly variable. The total lifespan of the insect is often said to be somewhere between two and three years.

A close-up view of the front end of an eastern Hercules beetle

A close-up view of the front end of an eastern Hercules beetle

The compound eye of the insect above can be seen behind the lower horn. The appendage attached to the mouthparts is called a palp. The palps of a beetle help to manipulate food.

Eastern Hercules Beetles

25. The United States contains two species of Hercules beetles that are related to the tropical species. They share features with Dynastes hercules, but in some cases these features are slightly different from their form in the tropical beetle.

26. The scientific name of the eastern Hercules beetle is Dynastes tityus. It lives in the eastern part of the United States. Texas is the western limit of its distribution.

27. The beetle is two to three inches long when the male's horns are included in the measurement. The horns are shorter than those of Dynastes hercules. The upper horn is referred to as the pronotal one and the lower one as the clypeal one. The pronotum is the plate covering the thorax. The clypeum is the lowest plate on the "face" of an insect.

28. The two horns are approximately the same size. The tip of the pronotal horn has a short bifurcation, which helps in identifying the species.

29. The male has a smaller horn on either side of his pronotal one, as shown in the photo above.

30. The pronotum and the elytra are yellow, tan, green, or grey and are mottled with black spots.

31. The surface of the beetle become entirely black in high humidity.

32. The insects feed on fallen fruit. They have also been observed feeding on the sap from ash trees. They aren't considered to be a pest, however.

Because of their large size and impressive horns, many people believe that Hercules beetles are dangerous. In fact, their horns are not dangerous at all, and the beetles are not known to bite. However, if you pick one up, it may scratch you with its strong, spiny legs.

— University of Kentucky

A male and female western Hercules beetle

A male and female western Hercules beetle

The American species of Hercules beetles reproduce by complete metamorphosis. This involves the same stages as the process in their tropical relative. The eggs, larvae, and pupa of the beetles develop in the soil.

The Western Hercules Beetle

33. The western Hercules beetle has the scientific name Dynastes grantii. The species name is sometimes written as granti, but according to entomologists this spelling is incorrect.

34. The beetle is found in Arizona, New Mexico, Utah, and northern Mexico.

35. Like its eastern relative, it's two to three inches in length.

36. Its pronotum and elytra are always grey-green in colour in a dry environment. The elytra are mottled with dark spots. The body becomes black in a humid environment.

37. The male's horns are noticeably longer than those of the eastern Hercules beetle. In addition, the pronatal horn is considerably longer than the clyneal one.

38. Unlike that of the eastern Hercules beetle, the pronatal horn doesn't have a bifurcation at the tip.

39. The insect feeds on the sap of ash trees.

40. Hybrids between the eastern and western Hercules beetles have been produced in the laboratory. Some researchers feel that the animals should be classified as members of the same species and that their differences are relatively minor geographical variations.

The two beetles shown in the video below have just come out of a humid box and are still dark in colour, particularly the female.

An Interesting Genus

It's still uncertain why the different types of Hercules beetles change colour. Since the nights are typically more humid where the insects live, the beetles change to a black colour at that time. One idea that has been proposed is that this darkening may be useful by providing camouflage. Another idea is that the black colour enables the beetles to absorb more heat during the cooler nights. Perhaps the change to a lighter colour is helpful during the brighter and often warmer day. Like some others characteristics of the animal, the ability to change colour is intriguing. Dynastes is a very interesting genus of beetles.


Questions & Answers

Question: Where are the antennae of the Hercules Beetle?

Answer: As in other insects, the pair of antennae are located on the first of the three body sections of the beetle, or the head.

Question: Are the Eastern and Western Hercules beetles rare? Are they only native to North & South America?

Answer: The Eastern and Western Hercules beetles are native to the United States. The western species is also found in northern Mexico. From what I've read, the eastern beetle is not considered to be rare, but it's not an abundant insect. The western beetle is said to be relatively common in Arizona, but not elsewhere in the United States.

Question: What purpose does the hair on the horn of the Hercules beetle serve? Seems a bit odd but quite attractive.

Answer: I haven't found information about the function of the hairs on the horn of the Hercules beetle, but I have for the hairs of other members of its family (the Scarabaeidae). In the beetle's relatives, the hairs have a sensory function.

Question: What was the biggest beetle ever recorded?

Answer: According to Guinness World Records, the longest beetle in the world is the titan beetle (Titanus giganteus) of South America. The body of this insect can be as long as six inches. The heaviest beetle is the larva of the Goliath beetle of Africa, which can weigh up to three-and-a-half ounces.

© 2018 Linda Crampton


Linda Crampton (author) from British Columbia, Canada on June 08, 2020:

That must have been an interesting discovery!

Laura on June 08, 2020:

Our 5year old granddaughter found one on its back helpless, on out porch this morning. Central Texas! Fascinating!

Linda Crampton (author) from British Columbia, Canada on May 19, 2020:

They are fascinating creatures. It's interesting to observe them.

Linda Crampton (author) from British Columbia, Canada on May 19, 2020:

Good luck with your project, Ollie.

Ollie on May 19, 2020:

Im using these facts for my homeschool rhino beetle project

David on May 19, 2020:

facinated by beetles

Linda Crampton (author) from British Columbia, Canada on March 24, 2020:

That sounds like an interesting craft, Denise. Thank you for the comment.

Denise McGill from Fresno CA on March 24, 2020:

I created a craft for children (mostly boys) who like bugs and beetles. One of them was the Hercules beetle. The kids loved the project and the giant beetle.



Linda Crampton (author) from British Columbia, Canada on March 06, 2020:

Hi, Peggy. Beetles are interesting insects to observe. I'm looking forward to seeing some soon.

Peggy Woods from Houston, Texas on March 06, 2020:

In that last video, the beetle that is black is like some that I have seen in our yard on occasion. I do not remember seeing one with the long horns, but if there are females, there are probably also males. Next time I will take a closer look. Thanks for writing another informative article!

Linda Crampton (author) from British Columbia, Canada on April 25, 2019:

Thank you for the comment, Amna. I hope your project goes well.

Amna farooq on April 25, 2019:

I was here to get some information about Hercules Beetles school project. I thought of getting tit bits from every website but it looks like you your information was exactly what i wanted .Thank you @lindacrampton for the information. I am so grateful to you:)

Linda Crampton (author) from British Columbia, Canada on December 19, 2018:

Thank you very much. I hope your project goes well.

MJ H. on December 19, 2018:

you're awesome, Linda! Im on here for my school project and its really helpful! thanks!

Linda Crampton (author) from British Columbia, Canada on December 11, 2018:

Thanks for the comment, Zia. I think the beetle is an interesting and attractive insect.

Zia Uddin from UK on December 11, 2018:

Never heard of this Hercules beetle of the Scarabaeidae family from South America and W. Indies until I saw this. It's exactly like the ancient Egyptian scarab. I wouldn't mind picking one up and get scratched by its hind legs. I like the idea of keeping one as a pet as you've mentioned above but I guess it wont survive in the UK, it's a tropical beetle.

Very interesting to learn about this Scarab, thanks for sharing.

Linda Crampton (author) from British Columbia, Canada on October 23, 2018:

Thank you very much for such a kind comment, Penny.

Penny Leigh Sebring from Fort Collins on October 23, 2018:

Wow! I didn't realize that their period as a larva was so long! Absolutely fantastic article.

Linda Crampton (author) from British Columbia, Canada on October 11, 2018:

Thank you very much for the comment and for sharing your experience, Chitrangada.

Chitrangada Sharan from New Delhi, India on October 11, 2018:

Excellent information about Hercules beetles. I have seen them many times. Good to know so many interesting facts about them.

As always, a well researched and illustrated article! Thanks for sharing!

Linda Crampton (author) from British Columbia, Canada on October 11, 2018:

Thanks for the visit, Larry. I appreciate your comment.

Larry W Fish from Raleigh on October 11, 2018:

Thanks for sharing this article, Linda. I always love an article that gives facts about something and you have done it well here. I have seen these beetles on a couple of occasions. Now I am much more educated. Thanks!!

Linda Crampton (author) from British Columbia, Canada on October 09, 2018:

Thank you for the comment, Liz.

Liz Westwood from UK on October 09, 2018:

This is a well-illustrated article presented in an easily-assimilated style.

Linda Crampton (author) from British Columbia, Canada on October 07, 2018:

Thanks, Heidi. The insects are certainly impressive. I hope you have a great Sunday and a great week.

Linda Crampton (author) from British Columbia, Canada on October 07, 2018:

Thank you very much for reading the article and commenting, Nithya.

Linda Crampton (author) from British Columbia, Canada on October 07, 2018:

Hi, Manatita. Yes, it is good that they're not dangerous to humans. The horns make the insect look fierce.

Nithya Venkat from Dubai on October 07, 2018:

Great article with many facts about this unique Hercules Beetles, always enjoy reading your articles. Learned a lot about this beetle, thank you for sharing.

Heidi Thorne from Chicago Area on October 07, 2018:

Wow, I hope I don't see these monstrous guys in my yard. Probably not here in the Midwest. But, again, another impressive member of the animal kingdom we know because of you. Happy Sunday!

manatita44 from london on October 07, 2018:

Pretty amazing facts about the hercules beetle. I like to see how they approach to fight. Not dangerous to humans, I see. Great!

Linda Crampton (author) from British Columbia, Canada on October 04, 2018:

Hi, Dora. Yes, the research is impressive. It's interesting to learn about the insects.

Dora Weithers from The Caribbean on October 04, 2018:

Impressed that the scientist can detail so many aspects of these small creatures. Interesting!

Linda Crampton (author) from British Columbia, Canada on October 03, 2018:

Thank you for the comment and the idea, Bede. The colour change is interesting. The possible reasons that I've included are just suggestions from researchers. It would be interesting to learn more about the situation.

Bede from Minnesota on October 03, 2018:

Your insect articles are interesting, Linda. Actually, they’re all interesting. It’s curious why these beetles turn black in humid weather. Perhaps when it gets humid, they seek shelter in dark places, such as between rocks and suchlike, where it’s nice ‘n cool.

Linda Crampton (author) from British Columbia, Canada on October 03, 2018:

Thank you, Eman. I appreciate your visit, as always.

Linda Crampton (author) from British Columbia, Canada on October 03, 2018:

Hi, Devika. I agree—beetles are fascinating!

Eman Abdallah Kamel from Egypt on October 03, 2018:

A very informative article, so much information about Hercules beetles. Thanks, Linda for this interesting article.

Devika Primić from Dubrovnik, Croatia on October 03, 2018:

Beetles are fascinating and to know what is going on in their world is sad.

Linda Crampton (author) from British Columbia, Canada on October 02, 2018:

Thanks for sharing the interesting comment, Mary. I feel sorry for the beetles, but watching their behaviour must have been interesting for the children.

Linda Crampton (author) from British Columbia, Canada on October 02, 2018:

Hi, Nell. I think the pupa looks very interesting. I think the insect looks beautiful, too, though I doubt whether many people would agree with us!

Linda Crampton (author) from British Columbia, Canada on October 02, 2018:

Hi, Bill. Yes, their size is impressive. They would certainly be hard to miss if they were in the open!

Mary Norton from Ontario, Canada on October 02, 2018:

I have watched kids play their beetles. They keep one in a match box and when the teachers are not paying attention, their boxes come out and the fights begin.

Nell Rose from England on October 02, 2018:

Wow! now that totally fascinated me! the Pupae film was amazing. I actually think the Hercules beetle is beautiful. Really interesting and amazing videos too!

Bill De Giulio from Massachusetts on October 02, 2018:

Hi Linda. What an interesting insect. Can’t say I’ve ever come across a Hercules beetle. Their size alone would be enough to scare the heck out of anyone who does not like insects. Thanks for the education.

Linda Crampton (author) from British Columbia, Canada on October 02, 2018:

I love the thought of the beetle being so ugly that it's beautiful! I appreciate your visit and comment, Jackie.

Linda Crampton (author) from British Columbia, Canada on October 02, 2018:

Thank you, Bill. I think it would be interesting to keep one of the beetles as a pet and handle it often, though it would be nice if the insect lived longer. I know it doesn't look like the ideal animal to hold in the hand, though!

Linda Crampton (author) from British Columbia, Canada on October 02, 2018:

Hi, Pamela. I know some people don't like insects, but I think they're interesting animals. I enjoy observing them, though I try not to get too close to the harmful ones. Thank you for the comment.

Linda Crampton (author) from British Columbia, Canada on October 02, 2018:

Hi, Flourish. Yes, sometimes the beetle does die. The insect's fate probably depends on whether it's injured as well as upside down. Thanks for the visit.

Jackie Lynnley from the beautiful south on October 02, 2018:

Quite interesting, Linda. This is one of those insect that is so ugly it is beautiful, especially the rhinoceros looking ones. Hard to stop looking at!

Thanks for the great info.

Bill Holland from Olympia, WA on October 02, 2018:

Fascinating creatures although I doubt I would want to hold one in my hand. :) Interesting as always, Linda!

Pamela Oglesby from Sunny Florida on October 02, 2018:

Linda, I am glad they are not found here even though they are harmless. I just don't like bugs very much.

However, this is an interesting study, and your article was very well written. I like learning about them.

FlourishAnyway from USA on October 02, 2018:

The horns or pincers are impressive as is their color changing ability. When the males fight and one is left upside down is he left there to perish?

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