Darkling beetles are a large and diverse family of beetles, with over 20,000 species worldwide. These beetles are typically black or brown, often dull in color, and are commonly found crawling on the ground. They play an important role in the ecosystem as scavengers and decomposers. Many people keep them as pets. This article will explore the diverse diet of darkling beetles, and some considerations for keeping them as pets.
Identifying Darkling Beetles
Darkling beetles belong to the Tenebrionidae family of beetles. They are invertebrates, specifically arthropods, characterized by "jointed legs." With as many as 10 million species of insects alive on Earth today, insects probably constitute more than 90 percent of all animal species.
So, how do you identify a darkling beetle? Here are some key characteristics:
- Color: Typically black or brown, often dull, sometimes shiny. Some species may have other patterns or colors, notably red.
- Size and Shape: Varies widely, but most are oval or elongated.
- Texture: The cuticle (exterior) is hard and thick.
- Antennae: Usually with 11 segments; appear beadlike or threadlike; often slightly clubbed (with the outer segments gradually wider).
- Locomotion: Usually by walking. Some species can fly and may be attracted by lights at night. Many species are flightless.
- Larvae: Hard-bodied, cylindrical, with 6 short legs behind the head. These larvae are often referred to as mealworms.
Adult darkling beetles range in length from less than ¼ inch to about 1½ inches. They can be found in various habitats, including forests and deserts. In the wild, they are often found under rocks and logs during the day, as they are ground-dwelling nocturnal beetles.
Darkling Beetles as Scavengers and Decomposers
Darkling beetles are scavengers and decomposers, meaning they feed on dead and decaying organic matter. This makes them important contributors to nutrient cycling in their ecosystems. They consume a wide variety of items, including:
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- Dead insects
- Fallen leaves
- Decaying wood
- Fungi
- Dead animals
They have chewing mouthparts that allow them to break down tough plant and animal material. As scavengers, they consume animals or plants that have either died naturally or have been attacked by another predator. In the case of plants, they will usually eat plants that have withered away and begun to rot. It is common to find darkling beetles in wooded areas and fields, as well as in parks, flowerbeds, barns, and other artificial structures that provide them with sufficient food.
Darkling Beetle Diet in Detail
A darkling beetle's diet is quite diverse. As omnivores, darkling beetles will eat a variety of organic materials. Some species are agricultural pests, attacking and spoiling stored grains and flour. Others eat living vegetation.
The larval form of darkling beetles, called mealworms, can often be found inside rotting stumps, logs, and rocks.
Darkling Beetles as Pets
Darkling beetles are a popular pet choice among bug enthusiasts. Since darkling beetles are omnivorous eaters, this means that they’ll eat a variety of organic materials. When keeping darkling beetles as pets, it is important to provide them with a varied diet.
Here are some food options for pet darkling beetles:
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- Oatmeal or wheat bran: This should be constantly available as a staple food.
- Fruits and vegetables: These provide moisture and essential nutrients. Good options include carrots, potatoes, celery, cucumber, and apples. Some keepers have found that their beetles have preferences, with some preferring celery and cucumber over carrots and potatoes. Zucchini may be more appealing to the larvae (mealworms) than the adult beetles.
- Protein-based foods: These can be offered in moderation. Options include dry dog food and crushed dried crickets.
- Avoidance of uric acid buildup: When feeding protein-based foods, it is important to also offer fruits and vegetables to ensure a balanced diet and prevent uric acid buildup.
One keeper shared their experience: "I’ve found mine have preferences. Most people feed their beetles carrot and potato but mine hardly touch them and seem to like celary and cucumber a lot better. They aren’t fans of zucchini, but the worms love those. Apple was a big hit too! Just keep trying whatever you have in the fridge and get to know your creature."
Another keeper mentioned feeding mealworms dog and cat food for years without any problems, suggesting that a varied diet can prevent issues like uric acid buildup.
Feeding darkling beetles moist foods during their mealworm stage will provide them with water. This can be accomplished with slices or pieces of fruits and vegetables such as potatoes and apples.
Water Acquisition
One of the most fascinating characteristics of darkling beetles is their ability to create water inside their bodies. This eliminates the need for external water sources for the beetles to survive. They accomplish this by constructing water molecules from other molecules within their bodies.
Predators and Defense Mechanisms
Due to their size, darkling beetles are eaten by a lot of bigger animals, including coyotes, foxes, hawks, snakes, leopard geckos, ravens, fish, and crows.
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As a means of defense, the darkling beetle has a very unique method. When disturbed, they lie on their backs with their tails up. In the event that they are handled roughly, they will release a foul-smelling, dark-colored fluid. This emission makes them unpalatable to would-be predators. In most cases, this behavior is enough to deter all but the most committed attackers from pursuing them as prey. When disturbed , they will stand on their heads and elevate their rear end and emit a foul-smelling odor. This behavior is often accompanied by the beetle standing on its head and elevating its rear end.
Are Darkling Beetles a Threat to Humans?
No, darkling beetles are not a threat to humans. In general, darkling beetles will run away from you or threaten to spray you with their foul-smelling liquid rather than bite you. It is important to note that the mouth of a Darkling beetle is equipped with mandibles, which are pincers designed to grasp food outside the mouth and chew it.
While darkling beetles are not generally considered dangerous, it is important to note that they are capable of spreading several diseases. A study published in 2008 hypothesized that insects like darkling beetles and their larvae might play a role in the transfer of pathogens from one life cycle to the next.