Just spotted this microscopic creature on an old book I haven’t touched in months. It looks like a tiny crab or a scorpion but it’s missing a tail. Is this some kind of mutation?

Pseudoscorpions primarily feed on small insects and mites. This diet makes them beneficial to humans, as they help control populations of pests that might damage books, food, or other household items. Common prey includes booklice, dust mites, and other small arthropods that thrive in homes.

By keeping these populations in check, pseudoscorpions help maintain a balanced ecosystem within homes and can prevent infestations of more harmful pests.
6. How Pseudoscorpions Hitch Rides Around Your Home
Pseudoscorpions have a unique method of dispersal known as phoresy, where they hitch rides on larger insects like flies or beetles. This allows them to move to new environments where they can find food and shelter. They use their pincers to hold onto the bodies of these larger insects, traveling significant distances in the process.
This mode of transport is efficient, enabling them to colonize new areas within a home, such as moving from the garden to the interior or from one room to another.
7. Should You Be Worried About an Infestation on Your Books?
Finding a pseudoscorpion on your books is usually not a cause for alarm. These creatures do not damage books or other materials; instead, they help protect them by preying on booklice and other pests. Infestations of pseudoscorpions are rare and typically self-limiting, as their presence depends on the availability of prey.

If you find multiple pseudoscorpions, it may indicate a larger population of prey insects, which might need addressing. However, the pseudoscorpions themselves are harmless and beneficial in controlling these populations.
8. Simple Ways to Check Your Home and Books for More Pseudoscorpions
To check for pseudoscorpions, look for them in dusty, undisturbed areas such as bookshelves, under furniture, or in corners. A flashlight can help illuminate these small creatures. They are often found in places with abundant prey, so checking for other small insects can also indicate their presence.
If you discover pseudoscorpions, it’s likely due to the presence of other tiny arthropods. Regular cleaning and reducing clutter can help minimize the habitat for both pseudoscorpions and their prey, keeping their numbers in check.
9. When (If Ever) You Need Pest Control for These Tiny Arachnids
In most cases, professional pest control is not necessary for pseudoscorpions. They are naturally occurring and beneficial, often reducing the need for chemical pest control methods. However, if their presence is accompanied by larger infestations of other pests, consulting a pest control professional might be advisable.

Addressing the root cause, such as reducing humidity or sealing entry points for insects, can be more effective than targeting pseudoscorpions directly. Since they are harmless, allowing them to continue their role in pest control is often the best approach.