What Do Darkling Beetles Eat: A Quick Guide for the Curious

Darkling beetles are fascinating creatures found in various habitats all over the world. You might have come across them in your garden or even during an evening stroll. These beetles are usually black or brown and can be quite intriguing to observe. Curious about what they eat? Let’s explore their diet and uncover some interesting … Read more

Darkling Beetle: All You Need to Know for Easy Identification and Fun Facts

Darkling beetles are fascinating insects that can be found in various habitats across the globe. These beetles are primarily known for their completely black color and unique defensive strategies, which they often employ to protect themselves from predators. Depending on the species, the shell of their abdomen can be either smooth or textured with ridges or bumps, making them an intriguing group of insects to study and observe.

One key characteristic of darkling beetles is their size, with some adults reaching up to 1.5 inches (3.8 cm) in length. These nocturnal scavengers feed on several types of “dead” materials like clothing, rugs, stored foods, and rotting wood, as well as fungi UWM Field Station. As their importance extends beyond their role in breaking down dead materials, darkling beetles also serve as a vital food source for many insect and animal species.

Darkling Beetles’ features:

  • Completely black in color
  • Smooth or textured abdomen
  • Scavengers on dead organic material
  • Can grow up to 1.5 inches

Overview of Darkling Beetles

Defining Features

Darkling beetles, as the name implies, are typically black or brown in color. These insects can have varying shell textures with ridges or bumps, depending on the species1. Some defining features include:

  • Black or brown coloration
  • Shell textures with ridges or bumps
  • Adult sizes up to 1.5 inches (3.8 cm) in length1

These beetles are known to walk with their heads down, making them easily identifiable1.

Tenebrionidae Family

Darkling beetles belong to the Tenebrionidae family, which is a very large and diverse group2. These beetles are commonly found in North America, with about 1,200 species identified3. They are generally small-to-medium-sized, slow-moving insects3.

The Tenebrionidae family is known for its nocturnal scavenger behavior, feeding on “dead” material like clothing, rugs, stored food, and rotting wood3.

Coleoptera Order

Darkling beetles are part of the Coleoptera order, which is the largest group of insects with one in four named insects being a beetle4. Key characteristics of the Coleoptera order are:

  • Biting and chewing mouthparts
  • Two pairs of wings; first pair being hard or leathery^[4^]

The first pair of wings, also called elytra, are not used in flight, but offer protection for the beetle’s body4.

Life Cycle and Reproduction


Darkling beetles begin their life as eggs. When they hatch, they turn into grub-like larvae called mealworms. These larvae are initially white but turn tan as they age. They undergo several molts as they grow.


After reaching their final larval stage, darkling beetles enter the pupation phase. During this period, they transform into pupae, an inactive stage similar to cocoons in moths and chrysalises in butterflies1.


The metamorphosis process in darkling beetles is known as complete metamorphosis. It involves four distinct body forms: egg, larva, pupa, and adult. Typically, a beetle remains as an egg for 7 to 10 days before moving on to the larval stage2.


Once the pupation stage is complete, the sexually mature adult darkling beetle finally emerges3. Adult beetles are known for their black color, and their abdomen shells can be smooth or textured with ridges or bumps, depending on the species4.

Darkling beetle comparison table:

Stage Description
Egg Initial stage; hatch into grub-like larvae
Larva (Mealworm) Grub-like appearance; molt several times as they grow
Pupa Inactive stage; similar to cocoon in moths or chrysalis in butterflies
Adult Mature, reproductive stage; completely black in color5

In summary, the life cycle and reproduction of darkling beetles involve:

  • Egg hatching into larvae (mealworms)
  • Larval growth and molting
  • Pupation and inactivity
  • Metamorphosis through four life stages
  • Emergence of mature adult beetles

Behavior and Habits

Natural Habitat

Darkling beetles are commonly found in the Columbia Basin and other areas of North America, primarily in the West. They thrive in environments with access to:

  • Dead plant or animal matter
  • Rotting wood
  • Fungi

Typical Diet

These little insects are omnivores and eat a variety of things:

  • Decaying plant matter
  • Fungi
  • Insect larvae
  • Dead animals

Adaptations and Defense Mechanisms

Darkling beetles possess remarkable defensive strategies:

  • Playing dead
  • Using chemical defenses

Their antennae are essential for detecting food sources and potential threats.

Temperature and Climate Impact

Temperature changes can affect darkling beetles’ behavior, distribution, and survival. A comparison table to illustrate the impact of different temperatures:

Temperature Impact on Darkling Beetles
Cold Slower movement, reduced activity
Warm Increased activity and reproduction

In conclusion, darkling beetles are fascinating creatures with unique behaviors and adaptations, thriving in various North American habitats. Their diet primarily consists of dead or decaying matter, and they possess notable defense mechanisms to evade predators. Temperature and climate play a role in their distribution and activities.

Darkling Beetle Infestations

Causes and Signs

Darkling beetles are nocturnal scavengers that feed on plant matter, pet food, and debris. They can cause damage to plants and stored products. Common causes of infestations include:

  • An abundance of their preferred food sources
  • Damp conditions or moist areas
  • Weeds and dirt clods providing suitable hiding places

Signs of an infestation include the presence of adult beetles, their larvae (mealworms and superworms), or wireworms. You may also notice damage to plants, textiles, or stored foods.

Prevention and Control

To prevent and control darkling beetles, follow these steps:

  1. Remove food sources: Keep pet food in sealed containers and clean up any spills promptly. Regularly remove dead plant matter and debris.
  2. Eliminate hiding places: Clear weeds and remove stones, dirt clods, and any other possible hiding spots.
  3. Monitor and trap: Set up sticky traps or pitfall traps to capture and monitor beetle populations.
  4. Apply insecticides: In severe infestations, consider using insecticides, but note that some darkling beetles can develop resistance.

Pros of using insecticides:

  • Can provide rapid control of infestations
  • Can target specific pests

Cons of using insecticides:

  • May cause harm to non-target species
  • Overuse can lead to resistance

Natural Predators and Enemies

Some natural predators and enemies can help control darkling beetles:

  • Ground beetles: Predatory beetles that prey on various soil-dwelling pests, including darkling beetle larvae
  • Birds: Many bird species feed on beetles and their larvae
  • Reptiles and amphibians: Lizards, frogs, and other small creatures can prey on darkling beetles and their larvae
  • Nematodes: Microscopic roundworms that can parasitize darkling beetle larvae

By promoting these natural predators in your garden or property, you can reduce darkling beetle populations without resorting to chemical insecticides.


  1. U.S. National Park Service 2 3 4

  2. Missouri Department of Conservation 2

  3. Field Station 2 3 4

  4. PNNL: Science & Engineering 2 3

  5. Darkling Beetles

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Stink Beetle


What Type of Beetle is this
Thu, Apr 30, 2009 at 8:42 AM
This was found on my back decl in Northern Nevada a couple days ago. It has a hard body and looks like it walks high. The deck is open air but has a sun cover over it to block the sun and the bug was under the shaded part
Yerrington, Nevada USA

Acrobat Beetle
Stink Beetle or Acrobat Beetle

Hi Lisa,
This lumbering beetle is a Darkling Beetle in the genus Eleodes.  There are numerous species in the genus found in arid regions of the Southwest, and we are not skilled enough to differentiate the species from one another.  These beetles are commonly called Stink Beetles because they emit an odor as a defense mechanism.  Because of their habit of standing on their head with the rear end elevated when disturbed, they are also called Acrobat Beetles.

Letter 2 – Stink Beetle


Think it’s a Darkling.
April 17, 2010
This thing came crawling out a hole in our brick wall when it noticed a puddle on the ground as a result of my watering.. I believe it’s a Darkling Beetle, But not sue exactly which kind.
Vince Grgas, San Pedro CA.
Southern Los Angeles area

Stink Beetle

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How to Tell if a Darkling Beetle is Male or Female: Easy Identification Tips

Darkling beetles are fascinating insects, but determining their gender can be a bit tricky. These nocturnal scavengers come in various sizes and forms, usually presenting a dark or brown coloration. Before we dive into identifying the gender differences, let’s get a clearer understanding of these beetles that are found in diverse habitats like woodlands, deserts, … Read more