Flour Beetles’ Biting Behavior: What You Need to Know

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We all know how big a pest flour beetles can by for your pantry goods. But do flour beetles bite as well? Can they cause you injury? Let’s find out.

Flour beetles are resilient pests that can survive pesticides and even radiation. They are a common pest in the tropics and sub-tropics.

As the name suggests, these tiny beetles feast on grains and flour and pose a serious threat to crops and the agricultural sector.

Flour beetles cannot bite or sting – their mouth only has chewing parts. However, they can cause allergic reactions, and infested food should not be consumed.

Do Flour Beetles Bite
Red Flour Beetle Source: SarefoCC BY-SA 3.0, via Wikimedia Commons

What Are Flour Beetles?

Adult beetles can be as long as 3/16 inches with a flattened, elongated body that is reddish-brown in color.

Their small bodies allow them to hide in tiny crannies from where they come out to feed on the food source.

They are a type of pantry pest that survive on grain products that are unprocessed, processed, or milled, such as whole grains, cereals, cake mix, pet food, dried beans, spices, and chocolates.

Flour beetle infestation at home can be managed by identifying the source and infested material.

Throw away everything that has beetles in it or packages with holes or leaks. These are probably infested. Alternatively, you can freeze all food items for longer than five days.

Next, you should thoroughly clean all shelves and containers with soapy water and then properly vacuum all nooks and crevices of your kitchen.

Do They Bite or Sting?

Flour beetles are munchers and can eat through grains and other produce. However, their mouth does not have stingers or biting parts.

Even with respect to grains, they can only feast on smaller, damaged pieces as opposed to robust, larger pieces.

CSIROCC BY 3.0, via Wikimedia Commons

Are They Harmful?

Flour beetles are not directly harmful to humans in both larval and adult stages as they do not carry human-infecting diseases.

However, they are pests that attract even large storage facilities and, thus, are very harmful from an economic perspective.

Capable of surviving with no water in very dry environments, these pests are quite difficult to get rid of.

They are highly resistant to many common pesticides used, such as malathion, DDT, carbamates, phosphine, and more.

Do They Cause Any Disease?

The red flour beetle specifically can result in allergies. These can manifest in the form of red swelling and contusions.

They do not carry any diseases and are frequently used as lab animals due to their low-maintenance nature.

However, they do act as hosts for tapeworms, and thus, ingesting them is not a good idea. Generally, this happens if they feed on rat feces that contain tapeworm eggs.

Flour Beetle Larva CSIROCC BY 3.0, via Wikimedia Commons

The tapeworm lives on in its body until the beetle is further consumed by some other pest.

They do not generally damage furniture (like some other beetles) or even chew through the undamaged grain. They feed on items discarded or already broken by other pests.

How To Differentiate Between Red Flour Beetles and Confused Beetle?)

Flour beetles can be either red flour beetles or confused flour beetle. Apparently, the latter received its name since so many people confused it with the former!

Both varieties look almost the same with a similar size and color. But you can distinctly identify them using their antenna.

The red flour beetle has antennae that are segmented into three parts and are shaped like a club. Their thorax or lower abdomen also is curved slightly inwards.

The confused beetle, on the other hand, has antennae with four segments, but it is not club-shaped.

Their abdomen is also more straight-shaped. Apart from this, both beetles have a similar diet, look-alike larvae, and can survive for as long as three years.

Source: Degesch, Source:PestWeb, http://agspsrv34.agric.wa.gov.au/ento/pestweb/Query1_1.idc?ID=-1919870117, This source is not copyrighted.

What Is The Difference Between Flour Beetles and Bed Bugs?

Some common differences between the flour beetle and bed bugs are:

Appearance: Bed bugs have shorter, rounder bodies with thin straight antennae. Flour beetle bodies are more elongated with a thicker antennae.

Diet – Bed bugs are parasites, sucking on the blood of warm-blooded animals. Flour beetles are scavengers that feed on grains and stored food products.

Life cycle – Bedbug nymphs look similar to bedbugs but are smaller in size. Flour beetles hatch into yellow-white larvae from their eggs.

Habits – Bed bugs can bite and suck blood. They will pierce your skin and leave marks. Flour beetles, on the other hand, cannot bite or sting humans.

Is it Ok To Eat Flour With Beetles in it?

Absolutely not!

Even if the beetles are not currently in the food, you can easily identify an infestation by looking at the color.

Common signs of infested food are a grey tinge and an unpleasant smell from the beetle. Since they cannot eat undamaged grain, you will find they mostly feed on broken kernels and leave grain dust around – a sign to look out for.

Their presence causes grains to host mold, and you might even find some eggs or larvae in the grains. Though they don’t carry diseases, some people can get allergies from the red flour beetle.

Moreover, they act as hosts (for some period of the life cycle) to tapeworms like Hymenolepis nana, which can transfer to a human and reside in them.

Some beetle-infested food (such as those infested by weevils) is still safe for consumption. However, flour beetle-infested flour should be given a hard miss.

Source: By Eric Day, Virginia Tech, Blacksburg, Va – http://www.genome.gov/pressDisplay.cfm?photoID=87, Public Domain, https://commons.wikimedia.org/w/index.php?curid=46686789

Frequently Asked Questions

Can flour beetles harm humans?

Not directly, since they do not sting or infect humans with diseases.
However, eating infested food with actual beetles or even their dead bodies can cause you to become the new host of a tapeworm or suffer from allergic reactions.

Why are flour beetles in my bed?

Flour beetles can move around quickly, and some, like the red beetle, can fly. They are attracted by light and scavenge around for food items.
Any place with spilled food can be a beetle residence, so if you tend to eat on your bed – it could be promoting their movement.

Do bugs in flour bite?

Many types of bugs can infest food storage, and cereal products kept within plastic containers.
Some common names include weevils, flour beetles, food mites, and other pantry pests. However, none of these bites or sting and thus are safe to touch.

Are flour beetles poisonous?

Flour beetles cannot inject poison or sting. However, it’s difficult to say that eating them will be fully non-toxic for someone.
Their presence promotes mold and fungal growth. Sometimes, they host tapeworms and other pathogens, which can cause health concerns.

Wrap Up

If you see flour beetles infesting your storage, don’t be afraid to start washing them out. Since they don’t bite, as long as you take proper precautions while cleaning out the spaces – you will be fine.

It’s best to call local experts for larger infestations due to their resistant nature. Thank you for reading!


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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