Spider Beetles Facts: Identification & Behaviour

Detecting an infestation of spider beetles can be challenging due to their small size and tendency to hide. In many cases, infestations are well advanced before people notice them.

The presence of a pupal cocoon or an adult spider beetle is the most apparent indication of an infestation.

These organisms are referred to as such due to their similarity to spiders. Certain species possess elongated legs, antennae that resemble an extra set of legs, and a body structure that may bear a resemblance to that of a spider.


What Do Spider Beetles Look Like?

Spider Beetles
The Spider Beetles [Picture]
Spider beetles are characterized by their small to moderate size. While there is variation in size among different species, the average length of these species is typically around 2 to 4 millimetres, which is equivalent to approximately 1/16 to 1/8 of an inch.

As their name suggests, these beetles have a striking resemblance to small spiders. The most noticeable characteristic of these organisms is their spherical shape.

When observed from above, their head is positioned downward and hidden beneath their body.

In contrast to real spiders, ptinid beetles possess the standard six legs that are characteristic of all insects.

Nevertheless, the antennae located on their heads frequently resemble an additional set of limbs. This characteristic enhances their resemblance to spiders.

The majority of species exhibit a colouration ranging from brown to reddish brown. Many individuals within this taxonomic group frequently possess a sleek exoskeleton, although certain species exhibit a body surface adorned with delicate filaments.

Certain species also exhibit unique patterns or markings. Spider beetles can be easily confused with bed bugs due to their round abdomen and reddish-brown colour.

The larvae of these organisms exhibit a C-shaped form and possess a pale colouration. Additionally, they possess fully developed legs.


Read also: Spiders In New York: What are the Top 5 Most Common?


Where Do Spider Beetles Live?

They can be found in diverse global locations. These beetles are capable of surviving in any area where human civilizations exist. They exhibit a widely distributed pattern in the areas where they are present.

Ptinids are a type of scavenger commonly found near stored food products. They can penetrate various locations, such as food production facilities, warehouses, grain storage units, mills, and museums.

These creatures may also infiltrate households by entering pantries, food storage cupboards, and attics that contain insect, bird, or rodent nests.

Spider beetles are drawn to areas that have high levels of moisture. Therefore, they are generally more prevalent during periods of rainfall.

The insects exhibit timid behaviour and tend to remain concealed for the majority of their time. Typically, they tend to conceal themselves within walls, cracks in wooden floorboards, and other secluded areas, ensuring they remain out of sight until nighttime.


What Do Spider Beetles Eat?

They do not have specific dietary preferences. Indoor pests that commonly infest stored products primarily feed on grains. Nevertheless, they can consume a diverse range of other food items, including:

  • Seeds
  • Almonds
  • Rye bread
  • Wool
  • Flour
  • Dried mushrooms
  • Animal skins
  • Wool
  • Silk
  • Books


Read also: Sac Spider Bite: Description, Signs & Treatment


What Eats Spider Beetles?

Spider beetles lack significant defensive mechanisms against predators. As a result, they are frequently the prey of spiders, lizards, birds, rodents, and other insect-eating animals in domestic environments.


Read also: How Often Should I Spray Vinegar For Spiders



Despite possessing mouthparts designed for biting, they do not consume blood. Instead, they consume dehydrated food substances.

If you observe reddish insects in your household that cause bite marks on your body, you may be encountering bed bugs rather than spider beetles.

If you are experiencing challenges in identifying the origin of an infestation, it is advisable to strategically position adhesive traps in various sections of your dwelling, particularly in locations where the beetles have been observed.

Rearrange the traps as you collect additional beetles to identify the affected material and eliminate it. When faced with a significant infestation, it is advisable to contact a professional pest control company.

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