Saturday, August 8, 2009

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.


12 comments:

  1. Man, thats one hot Asian.

    ReplyDelete
  2. this is awesome and nice title btw

    ReplyDelete
  3. I thought I would throw in a vocabulary word here. The adjective describing an organism that uses another for transportation without harming it is "phoretic". Try that next time you carry your kid piggyback!

    For those who have never anesthetized a cockroach, you may be surprised and even horrified to learn that they have the same reaction as humans, and can sometimes lose control of their bodily functions. So in addition to the anxiety some people feel in handling cockroaches, let alone mites, there was also the sheer ickiness of bug vomit.

    ReplyDelete
  4. Nice going, Adrian! Keep us posted on how the flour dusting goes..

    ReplyDelete
  5. Fascinating article. I have a question: why is it necessary to keep the mite population so low that visitors are unaware of it? A little information placard next to the MHC tank, explaining that tiny, harmless mites use the roaches for transportation, would enhance the exhibit in my opinion.

    ReplyDelete
  6. Response to August 17th post.


    Actually (Anonymous) your post was made complete sense. It really is not necessary for us to remove any of the mites from the cockroaches on our exhibit display. However, our staff does a heavy amount of cockroach handling with the public. Visitors are encouraged to learn more about these insects through our staff/visitor handling program. These mites which usually stay on roaches can crawl on to visitors' hands during handling. For this reason, I wanted to minimize the number of mites on each roach, but eradication was never my goal. I wanted to learn the most effect way of controling these mites so testing with the exhibit roaches was a way to learn more about it.

    ReplyDelete
  7. I am a biology teacher in Nashville, Tennessee. Over school breaks and in the summer, I house my Hissers together with two large hermit crabs. They get along great and seem to be only somewhat interested in each other. The mites are also on the hermits but seem to do no harm. This arrangement has worked well for two years now.
    My latest and only concern to date is an infestation of wood mites from a log I placed in the cage. I have removed the section of wood, but the mites keep returning to the coconut substrate. The hermits do not approach the hisser egg cases. The hissers keep away from the hermits salt water bowl but share the fresh water source. They know the difference.
    If you have any advice for me regarding the returning wood mites, e-mail: ellerco@bellsouth.net

    ReplyDelete
  8. Not sure if this is still actively read or replied to, but I do have a quick question on the topic. Has anyone had any experience with these mites transferring to another roach species?
    I recently recieved a colony of hissers who all have the mites. I also have a colony that has no mites, as well as several colonies of other species. As of now, the new colony is quarantined, but I don't know if I should simply bleach the whole colony and start fresh, or just leave the mites be and not worry about it. Anyone have any advice? Thanks!

    ReplyDelete
  9. Hey, so i have two hissing cockroaches and they also have mites. I was wondering if it would be harmful to feed them to my bird eating tarantula?

    ReplyDelete
  10. Hi all you cockroach fans. Lindsey I do not see an issue with feeding the cockroaches to your spider. The mites should be host specific at least to within a greater degree than jumping from cockroaches to spiders. At any rate the mites are harmless to the carrier.

    ReplyDelete
  11. I use the flour, then either lightly spay with water or just blow it. Doesn't get rid of the mites, but sure cuts down on them. I do it about once a quarter. Doesn't bother them at all. Val

    ReplyDelete
  12. Good read. I have kept Giant Hissers for a few years now and my colony has always been mite-free, but I recently added a pair of black phase Giant Hissers and a pair of Halloween Hissers to the enclosure, and soon after, found that the four new roaches, though purchased in person from a very high-end breeder (Kyle K. from RoachCrossing.com), had these mites. I separated them as soon as I noticed the mites and went over my remaining 25-30 adult Giant Hissers and did not find any had transferred to them yet, but after reading several articles on the symbiosis-like relationship, I decided it isn't a huge deal and put the four new roaches back in the colony of Giants. I did greatly cull the number of mites (with tweezers) on the male Halloween Hisser, but I do keep my colony with no substrate and at low humidity, which if I understand correctly, is less than ideal conditions for the mites, so I don't think it will really be an issue. I just hope they do not transfer to my Dwarf Caves, Discoids, Dubia or Ivory Heads.

    ReplyDelete