Stage beetles live almost their entire lives underground, but what does a stag beetle eat when it finally comes out as an adult? Let’s find out.
A stag beetle is a rare and beautiful insect known for its long and threatening mandibles. However, these large jaws are more bark than bite.
While the larva of the stag beetle feeds on dead wood, including tree barks and saps, the adult doesn’t require eating and uses up the energy stored from larva food.
To learn more about what these interesting creatures feed on, continue reading.
What Is a Stag Beetle?
Stag beetles come from the age of the Jurassic Period, about 150 to 160 million years ago.
There are about 1200 stag beetle species worldwide, but you’ll find most of them in Europe and North America.
Stag beetles are quite a rare find these days. Collectors pay thousands of dollars for them.
They are experiencing decades of decline (due to the loss of habitat and food sources). For insect lovers, the best place to look for them is the UK.
What Does It Look Like?
Stag beetles are giant insects with a hard outer shell and two pairs of wings. The average length of an adult male stag beetle is between one and two inches.
However, the giraffe stage beetle, commonly found in southern Asia, can grow up to five inches long and is one of the world’s largest beetle species.
The most prominent feature of stag beetle is their mandibles (1.4-2.1 inches), which resemble the antlers of a deer.
With these massive jaws, an average adult beetle can be up to 3 inches long, making it the largest beetle in the specie in Europe.
Stag beetles are usually black or brown, but some species, like the Australian rainbow stag beetle, may also be colorful.
The male adult beetle is larger than females, primarily due to bigger mandibles. The stag beetle larvae, however, are even larger than the male beetles, with an average length of three inches.
Where Does It Live?
There are more than a thousand species of stag beetles across the world. However, you will find the most popular kind of stage beetle species in the UK:
- Lucanus Cervus,
- Dorcus paralellapipidus (relatively smaller than Lucanus Cervus), and
- Sinodendron cylindrical (also known as rhinoceros beetle).
In the US, you can find the cottonwood stag beetle in the state of Arizona on the southwestern side. A variety of these beetles also live in Australia and southern Asia.
Stag beetles can be found in areas with less rainfall and high temperatures since they spend most of their lives underground.
Thus, a hot and humid climate is good for the survival of these species.
What Does It Eat?
A typical stag beetle diet includes fluid from tree sap, tree bark, tree stump, wood, or decomposed fruit.
They usually rely on sweet fluids, but there is a difference between what stag beetles eat as an adult and as larvae. Here are the differences.
The larva uses its jaws to cut through dead wood to find the splinters and looks for the white rot to feed on.
Amongst the trees, larva usually likes the rotten wood of oak trees but would also eat up willow, ash, lime, sycamore, horse chestnut, etc.
Since they eat only dead wood, the shrubs and plants remain unharmed but don’t spare organisms like fungi.
Stag beetles spend most of their lives underground as larvae. When they finally become adults, they only have a few weeks of their lives left.
They do not eat much during their adult life. They use up the energy of the food they eat during the larval stage, and their primary concern is to reproduce.
What Eats It?
Stag beetles have predators like crows, foxes, lizards, amphibians, small mammals, kestrels, and birds.
Depending on the insect’s habitat, the predators may also include bats, raccoons, hedgehogs, skunks, moles, rodents, snakes, frogs, fish, dragonflies, ants, spiders, even other beetles, etc.
Predators often look for them during their mating season since they are vulnerable at that time.
Unique Mating Habits
The massive mandibles of the male stag beetle are used to fight other male contenders during the mating season.
With their antler-like mouths, they fight the other male aggressively to remove him from the way so it can mate with female stag beetles.
The male uses its mandibles as a warning signal to the competitors by raising its body to stand on its hind legs.
It can aggressively pick up and throw the opponent to the ground using the same posture, much like a wrestler. The winner of these battles is the one who gets to mate with the females.
If the rivals are endowed with equal-sized mandibles, these battles can last quite a long while. But in the end, it’s almost always the one with the bigger claws who wins.
Size does matter, at least in the insect world!
Apart from eliminating its rivals, the male beetle also uses its mandibles to court the female. The male circles the female with the “antlers.” while mating.
Frequently Asked Questions
What can I feed a stag beetle?
An adult stag beetle usually relies on the energy stored from the food consumed during the larval stage. They don’t live for longer than a few weeks.
A larva feeds on dead wood, including tree sap, tree bark, etc., of trees like oak, horse chestnut, and willow.
How do you keep a pet stag beetle?
Keep the beetle in a plastic or glass box with humid soil and good ventilation. Keep the temperature hot and humid, and ensure the box is at least five times larger than the beetle.
Make sure to spray some water in the jar regularly and feed them beetle jelly once or twice a day.
What do stag beetles need to survive?
Stag beetles spend most of their lives underground and, thus, survive easily in a hot and humid environment. They prefer to live in areas with low rainfall and high temperatures.
Females prefer light or flaky soil where they can easily lay their eggs, so they can easily dig out of the soil after pupating.
How long do stag beetles live?
Stag beetles can live up to 7 years, which is considerably longer when compared to other insects. However, the stag beetle spends most of its life as a larva and stays underground.
They come out of their cocoon after six years as pupa and turn into adults after a few weeks.
We hope this article helped you learn something about these beautiful creatures. With a rapid decline in their population, stag beetles are becoming harder to find every day.
These insects feed on a variety of dead wood, helping to decompose it. They don’t cause us any harm, and we are the ones causing much harm to them.
Thank you for reading!
Stag beetles are magnificent creatures to watch from up close. Over the years, we have had many readers inquiring about these insects, what they eat, how they mate, and so on.
Read on to go through some of these emails, and some more details that we have not been able to cover in the article above.
Letter 1 – Stag Beetle
need help! I live in Minneapolis, Minnesota..and the past two weeks we have been infested with these bug in the back yard. They have not made it inside the house yet, thank goodness! It pinched my husband the other night while he was outside and it latched on to my Westie’s nose, and sent her barking and crying! >Can you help me? We have asked all of our neighbors and no one has ever seen anything like this in our area. What is this thing? And how do I get rid of it? Thanks, Heather Hi Heather, This is a Stag Beetle. We are not certain what species, and we will enlist the assistance of Eric Eaton with a more exact identification. You must have a plentiful larval food source in your immediate vicinity. The grubs eat rotting wood, so perhaps a dead rotting tree or a neglected firewood pile is the source of the Stag Beetle population explosion. Update: (06/29/2008) About the Stag beetle Dear Heather, I know it’s not great to get pinched, and I am sorry that happened to your husband and your dog, but please don’t try to eliminate your stag beetles, they are a vital part of the forest ecosystem. Probably where your house is now used to be forest not too long ago, or perhaps you are near the edge of forest still. It sounds as if this year there is a surge in the population of stag beetles, and right now the adults are all hatching out, but very soon they will all disperse to find other dead wood, and you won’t be bothered by them any more. Stag Beetles are impressive, and to me they are some of the aristocrats of the beetle world. Best to you, Susan Update: (06/29/2008) Dear Daniel: The stag beetle is either a female or “minor” male of the “pinching beetle,” Lucanus capreolus. Am I going to hell because I laughed at the poor doggie? I can’t imagine an “infestation” of stag beetles, but simply turning off the outdoor lighting would help. They are attracted to lights at night. In the absence of that attraction they will probably fly elsewhere to look for mates. Eric Eaton Thank you so much for your response and your assistance. Now that we know what they are, and that they are not a threat or anything, we will let them be and hopefully they will move on soon on their own. No one will be going to hell for laughing at the fact that my poor puppy (only 12 weeks old) got “pinched.” It was quite the sight and we laughed too. 🙂 Thanks again! Heather Correction: (07/04/2008) Forwarded by Eric Eaton Hi Eric! I had a look at What’s That Bug , and would like to suggest that this entry Stag Beetle is probably a Lucanus placidus. Once I had an interesting correspondence regarding this species from Minnesota as well, and posted the lot in the bugguide. Interesting to know that it is you running this site, I used to visit when I had a lot a stag beetle emails, this before the emergence of the bugguide! All the best, Maria
Letter 2 – Stag Beetle Population Explosion
http://bugguide.net/node/view/3103100s of stag beetles Location: Wayne Michigan June 5, 2011 12:01 am i have hundreds of stag beetles in my yard. i can step foot in my yard. with out one pinching me. i do not live by woods im actually in the middle of a neighborhood. We have also found 100s in others neighbors yards. i know they are a vital part of mother nature but is there a way to get them to move other then trying to catch them. we have alot of young kids in our neighborhood and they seem to like there toes as well as our curious animals. Signature: Please Help Me. Sincerly Vanessa Hi Vanessa, Your email has us most curious. We cannot imagine why you have such an incredible population explosion of Stag Beetles. There must have been a bounteous food source for the larvae which take several years to develop. Stag Beetle Larvae feed on rotting wood. Are there numerous fallen or dead trees in your yard or in the neighborhood? Perhaps you have a large wood pile nearby. While we sympathize with your dilemma, we don’t really have any advice for you. Stag Beetles are not dangerous to humans or pets, and if they do happen to nip at skin, there should not be any lasting effects or any health concern for either you, your children or your pets. We don’t believe your Stag Beetle is the Reddish Brown Stag Beetle, Lucanus capreolus, but rather, we believe that based on BugGuide it is Lucanus placidus which is described as “Similar to L. capreolus, but much darker, elytra more punctate. Legs dark reddish brown, no light brown patches as in capreolus. Several small teeth on inside of mandibles of male–capreolus has only one.” According to BugGuide, the definition is: “punctate – marked by spots, dots, points, depressions, or punctures.” We have used the levels control in PhotoShop to lighten your image to better reveal the texture of the elytra, which appears to be punctate. Your beetle has two distinguishing features for Lucanus placidus, that as well as the toothed mandibles. We wish you could send us a photo of a large group of these Stag Beetles, possibly even a mating pair.
Letter 3 – Female Stag Beetle from the UK
Subject: Dark brown/black bug with pincers Location: Buckinghamshire UK July 17, 2017 7:10 am I found this bug in my bedroom by the window, I think it’s a stag beetle but I don’t know for sure… Signature: C Dear C, You are correct that this is a Stag Beetle. We believe it is a female Stag Beetle. They are sexually dimorphic, and Stag Beetles–All they need is love and wood has a nice image depicting a pair. You might want to consider registering your sighting as indicated here.