Hisser Mites

Animal Caretaker Adrian Eng and Discovery Corp Summer Intern David are waging war on the tiny mites that live on our Madagascar Hissing Cockroaches. This is Adrian’s first report from the front.







If you’ve ever handled a Madagascar Hissing Cockroach, you may have noticed some teeny tiny invertebrates crawling across their exoskeleton. These are mites and they call the cockroach’s body their home. Like travelers on a cruise ship, they move to and from different food sources utilizing our beloved roaches as their mode of transportation.


This mite species, Androlaelaps schaeferi, is not a cockroach parasite, as some scientists and hobbyists first believed. Instead, they perform commensalism, where one animal benefits while the other is unharmed and unaffected. A recent study from scientists at Ohio State University suggests they may even be beneficial to cockroaches, feeding on organic matter that would otherwise grow fungus. As beneficial as these mites may be, at Pacific Science Center we felt that an excess growth of mites was overly disturbing to the many staff and visitors that handle our cockroaches every day.

I teamed up with our Discovery Corp Summer Intern David and decided to wage a war with the mites. Our first goal was to reduce mite populations so that people are at least unaware of their presence. Our second goal is to figure out how to keep the mite population manageable in the long term.


We came up with a few techniques. Sweeping the mites with a soft brush seemed the most obvious choice. We also used very fine tweezers to remove mites one by one. This method was very tedious but effective. A more aggressive approach was dunking the roaches in water, which helped to loosen and dislodge the mites living on the body. This seemed uncomfortable and possibly dangerous for the roaches and the outcome was only moderately effective.


The most aggressive approach was using CO2 to incapacitate both the mites and the roaches. When they were both knocked out we were able to use an air canister to easily blow the mites off. This seemed the most effective technique but also the most invasive. Another suggested method was to dust the roaches with flour, something we will have to test the next time around.

This weekend we will begin our second round of treatment. I recently checked in on our roaches only to find that most of the mites have already returned in just a few weeks. As disappointing as this news can be, we are still determined to control the population of mites and are excited to find the best way to procure happy handlers and happy cockroaches.