Hello all, Many thanks again to all who wrote to me with advice on dealing with mite infestations...most helpful! Several people have contacted me who are interested in the responses as well, so I have pasted them below to share the wealth.... Cheers, Sam ************* Hi Sam it is fairly straight forward to get rid of mite infestations in fruit flies, especially if they are not specific parasites of the flies. First try to keep all lines quarantined so that you contain the mite infestation, best by keeping the bottles/vials in water baths (trays with water)- that prevents mites from spreading between lines. Then move flies onto new fly bottles/vials as soon as they emerge from the pupae, you can also move them to fresh vials in a series of 2-3 days. Make sure that you keep the fly room clean of dust, food sources for mites remove potential hiding places. Use cleaning ethanol or bleach to keep surfaces clean. Mites can be quite resistent to adverse conditions, so you need to keep this proceedures up for some time. You can place trapping vials in your fly room in order to access how much flies there are around. Very important- if you recycle your containers then keep glass wear very clean and autoclave foam stoppers- or use one way cotton wool. good luck- you should be able to get rid of the mites in a couple of fly generations. Markus Dr. Markus Riegler School of Integrative Biology University of Queensland St. Lucia QLD 4072 Australia phone: (++617) 33469218 fax: (++617) 33651655 mriegler@uq.edu.au *********** Hi Sam. You have food mites. I'm sure you've heard from others about this, but yes, you can try outrunning the mites. Transfer the flies to new food daily for a week or so. And make sure the food is relatively fresh. Also, bear in mind that there might be mite eggs everywhere. Use alcohol on all bench space and be scrupulously clean. You might also want to clean out the incubators that you have been using. As soon as you finish with food, dispose of or clean the vials. Old food sitting around is a common cause of mite infestations. Finally, remember Ashburner's warning from his 'Grey Book'--mites can appear by spontaneous generation. Oh, and don't trust anyone who sends flies claiming them to be mite-free. Always put incoming flies through quarantine. Good luck! Daniel Promislow *********** Sam, Good luck. I may have sounded too negative about the Tedion. I may have helped, and it's certainly easy to use. If hygiene and some judicious benzyl benzoate don't completely control things for you, try adding the Tedion paper bits to the mix to controls. Ian Ian A. Boussy iboussy@luc.edu Dept. of Biology 340 Quinlan Life Sciences Building Loyola University of Chicago 6525 N. Sheridan Rd. Chicago, IL 60626 tel. 773-508-3635 fax 773-508-3646 "Time flies like an arrow, but fruit flies like a banana." --Groucho Marx >>> >>> 10/08/06 10:56 AM >>> >>> Hi Ian, thanks for the advice! I was going to order some tedion but now I don't think I will bother...I'll probably try using multiple rapid transfers plus benzyl benzoate and a heavy cleaning to stop recontamination. Cheers! Sam Sam, Mites can be difficult to deal with. Without seeing them, from your description it sounds as though you're dealing with an Acarid mite, probably related to (but not the same as) the dreaded "red" mites that can form a hypopal form as a second instar. This hypopus is the "parasitic mite" that is shown on a website from Arizona. It's actually a travelling stage of the mite, which doesn't feed at all but only rides, and not actually parasitic at all. Unfortunately, large numbers of hypopi riding on a fly impede its ability to do anything, including mate or eat. For them, transfer definitely works with modest infestations because the hypopi leave the flies eventually when they find themselves in a new place. The hypopi are reddish, and, when numerous, may crawl up the sides of a bottle and congregate at the plug, forming a red ring that strikes fear into the heart of a drosophilist! I have had mites in the lab that a noted acarologist said were the same species as that which form hypopi, but that never formed hypopi! They are "food mites," related to stored grain pests, that are basically interested in the food, not the flies. Getting rid of them can usually be accomplished by changing flies to new food many times, and using cotton plugs, which they can't get through. Foam plugs are no barrier at all, and rayon may not stop them as well as cotton. I've used bits of paper towelling with Tedion, a miticide, soaked into them. This is described, I think, in an old DIS. (I'm at home or I'd look up the reference for you.) It might give some protection to put a tab of Tedion-paper in each vial each generation, but Tedion-paper doesn't kill off mites already in residence. Although I have used Tedion-paper for months at a time, I am not convinced that it really did much. The Acarid mites we're discussing are general detritus feeders, easily found in large numbers in soil and compost piles, and may well be widespread in your building, so the fly vials or bottles must be kept free of them. Some people used to use benzyl benzoate, spread on the tray holding the bottles or vials, to stop mite movement. I suppose it worked. It also made the bottles and vials very repulsive to handle; benzyl benzoate is a clear, slightly smelly, slightly oily substance, about the consistency of light mineral oil. It soaks into your skin, and you can smell it for hours after handling such bottles. But some labs use it. A friend of mine from japan brought anti-pest paper from Japan, impregnated with some pesticide, and used that on trays, placing vials and bottles on it. I don't know if such paper is advisable, but it didn't seem to harm the flies. Good luck. Ian Ian A. Boussy iboussy@luc.edu Dept. of Biology 340 Quinlan Life Sciences Building Loyola University of Chicago 6525 N. Sheridan Rd. Chicago, IL 60626 tel. 773-508-3635 fax 773-508-3646 "Time flies like an arrow, but fruit flies like a banana." --Groucho Marx ************ Washing the pupae before fly emergence for a couple of generations, combined with thorough cleaning of culture room, etc, ought to get rid of the problem. Good luck! Lex Fly, you greatest fool Why can't you say what they want you to Why can't you do what they taught you And show what they wanted of you Dr Alex R Kraaijeveld School of Biological Sciences University of Southampton Bassett Crescent East Southampton SO16 7PX tel: (+44)-(0)23-80593436 ************* Hi Sam, I'm sure you'll get a dozen replies, but when I had a similar problem, I fixed it with the following labor-intensive method. Allow flies to pupate, take a few pupae and physically wash them with a cotton swab and H20 under the dissecting scope, put pupae into fresh media. This did the trick, and I didn't lose any lines. I was keeping inbred isofemale lines, so the bottleneck was not a problem. This experience, however, did contribute to my switch from drosophila to infectious disease.... cheers, Mark ******************** Mark A. Jensen, Ph.D. Asst. Professor Dept. of HABE (Epidemiology) College of Public Health, and Dept. of Genetics Franklin College of Arts & Sciences University of Georgia N132 Coverdell Center Athens, GA 30602 ************** Hi Sam, the best way is to transfer adult flies by looking at them with CO2 under the scope, and remove any acarids or any eggs on their wings, if you keep tossing the vials you may transfer mites. Anne ************** Dear Sam-- You can flip them every 12 days or so (as soon as adults emerge). This will certainly help diluting and outrunning them. If the problem persists, you can try to pick individual eggs and then put them through a few rapid transfers. It is a difficult and persistent problem. Like a common cold. Sincerely, Dmitri phone (Coverdell) 706-542-2423 fax: (+44)-(0)23-80594459 http://www.sbs.soton.ac.uk/staff/ark/ark.php ************ Using mite paper and series of transfers within a day (such as 2-3 times of all boxes one after other in the morning and repeating the procedure at night) are the key. Also keeping the chamber or any place clean are very important. This method uses a lot of food (however you can put only a tiny amount in the vials) but definitely helps. Always autoclave the glass fly vilas or use clean plastic vials. I hope this will be useful **************************************** EFE SEZGIN Dept. of Ecology and Evolution SUNY at Stony Brook Stony Brook, NY 11794-5245 lab: 631/632-8586 fax: 631/632-7626 e_sezgin@life.bio.sunysb.edu **************************************** ************* The other quick step is to transfer the adults to several bottles before the ones used for rearing - i.e., prepare a generations as usualy, 48 hrs later move adults to new botles, discarding old ones, repeat that step again in 24 hrs, then also be careful not to let cultures get old for awhile. Do this for ALL populations in your paboratory, or the weker selection lines will be reinfected. Wash all surfaces concurrent with the first transfer to new bottles. And, use only cotton tops - rayon or paper bottle tops are not sufficient to contain mites to the infected bottles. [experience gained from sharing a lab with someone known as the mite woman, a name that had nothing to do with her short stature]. Regards, Bob Krebs -- Dr. Bob Krebs Dept. of BGES Cleveland State University 2121 Euclid Ave. Cleveland OH 44115 ************* Hi -- Ashburner's book covers this problem. What you have to do is change the stocks frequently in addition to doing the disinfecting. The mites have about a 3 week generation time so you are right that you can outrun them. You may need to do daily changes for a week or so; in the long run you should not let any containers of flies sit around if you don't need them further. It might help to require that everyone wash their hands thoroughly between handling different stocks. Cleanliness and quarantine of incoming stocks are the best defenses against mites. I don't recommend miticides because they kill flies as well. I have used an anti-bug shelf lining paper (I think we got it from Carolina) in a very limited way -- it prevents the mites from walking between stocks. You could use it under the most heavily infested stocks if you need to keep the stocks but don't want the mites to spread. I found that a few square feet (10-15) in a 6ftX8 ft chamber did not produce enough volatiles to injure the other stocks. Even so I'm not sure I would use it at all during the course of a selection experiment. good luck! ************* Hi Sam, One of my first duties after joining a fruit fly lab a few years back was the rehabilitation of many trays full of mite-infested stocks. Here are a few of my suggestions for dealing with your "food mites": 1. Always consult Ashburner (the fly bible) for any fly culture problems. 2. Keep all infected stocks in a separate quarrantine room in trays enshrouded with cheesecloths or paper treated with an anti-mite agent (I'm blanking on the exact name of the chemical, but it is available through sigma and I believe Ashburner makes mention of it. The chemical works by disabling the mites' ability to move between bottles/vials covered by cloth treated with the agent). 3. Bump the stocks religiously (~ every 14 days, provided they are healthy enough). Autoclave discarded, older vials immediately. This is the only way to "outrace" the mites. Also perform intensive visual examinations every few generations to ensure that mites are not piggy-backing along. Look for both the presence of mites and their incredibly small eggs (sometimes they stick to adult flies!). Our standard was 3 generations of religious bumping, inspect, then 3 more generations of bumping. If no mite indicators were present after the second inspection, the stock was considered "clean" and moved out of quarrantine. You can be more stringent if you like. 4. Never store any old discarded stocks in/near the kitchen where fresh fly food is made, and never leave extra food lying around for the mites to infest - autoclave old, unused food with along with discarded stocks. 5. Treat your incubators. I've frozen incubators outside (reccomended is -20'C for a few weeks, but a good stretch of below freezing weather seems to work), and fumigation is a possibility. The key is to kill off the ones living in the insulation. 6. If an infestation is persistant, you can also re-start a stock by transferring individual eggs to a new bottle/vial. I've never had to go this far, but I believe that you can also purchase chemicals to treat the eggs during the transfer process. Best of luck, MAH Chris ************* Hello Dr. Yeaman, I used to work on a long-term selection experiment on D. melanogaster. I got the same problem, and figured out a recipe to control mites. Please find the attached paper for composition of media. Remember, though, that getting rid of mites is not so easy if you have thousands of flies in a cage, and you need to be careful to not select flies by strong propionic acid and Nipagin. When mites overcome flies, putting a propionic acid-treated paper into the food is an option to provide flies an escapement. Good luck, Hitoshi Hitoshi Araki Dept. Zoology, Oregon State University arakih@science.oregonstate.edu ************ Hi Sam, The mites you have may not be predator mites but they do compete with the Drosophila for food, resulting in underfed larvae and weak lines may crash. You can out-run the mites by daily tipping over of the flies for a week. Kill and throw out these tips and then save subsequent ones for the next generation. You may need to repeat the process for the next generation. During this time, quarantine all infected lines by keeping the vials/bottles spread out, standing in about one inch of water to which a little detergent has been added to break the surface tension. This will prevent the mites from crawling from one vial to the next. Use disposable plugs and keep all surfaces clean with 70% ethanol. ************ I would also tip them over every day for a week between each of your rapid generations. Francis Jiggins, fjiggins@staffmail.ed.ac.uk ************ Hi Sam, mites are really a pain in the neck.... We had loads of trouble with them in our D. montana populations, but also sometimes in the melanogaster strains. Changing vials in a rapid succession is a good idea and might work. However, you might want to prevent the mites, which might survive in some vials, from infecting again the clean ones - we tried successfully to keep the vials on trays which are laid out with an anti-mite paper (you can get that from an American company, unfortunately I can't remember how it is called - if nobody else from the evoldirers suggests it, write an email to Tanya Sneddon in St Andrews, she knows the details of the product, th8@st-and.ac.uk, send her my regards :-)). Another but much messier method is to fill trays with a layer of any kind of oil or parafin or so and keep your vials in there, so that mites that try to walk over to new hunting grounds get stuck. I used household veggie oil, and it did work, but as I said, it is a rather messy solution. I guess it also makes sense to keep the vials so far apart that it is not possible for mites to crawl throught the cotton wool or stoppers over to the next vial. Rightyho, that's it with my advice on how to get rid of the little buggers, good luck with it, cheers Kirsten *********** Dear Sam, I did my PhD in Drosophila and we had a couple of mite episodes. The best bet is as you suggested, rapid transfers and careful cleaning. A couple of tips: once your adult flies lay a batch of, say, 20 or so eggs on the food, remove the adults immediately (and along with them any mites that might be on their bodies and ready to jump to the next generation) and do a visual scan for mites. Then, when the new generation of flies ecloses, transfer them immediately to a clean vial. When you transfer, do not simply tap one vial on top of another as usual or mites will just come through. Rather, gently sort the recently eclosed flies on a CO2 pad and visually scan for mites. Good luck, Karen Karen E. James, PhD Department of Botany The Natural History Museum Cromwell Road London SW7 5BD ************ Might work. Also, if you do not have too many stocks, pick pupae soak them quickly in water and place in a vial. Should remove mite eggs. Ron There are also chemical ways. Go to Flybase. rwoodru@bgsu.edu ************ Aloha Sam, We have had luck keeping infestations down in our Hawaiian Picture-winged Drosophila, by surrounding all the jars with diatomized "soil". You can create a mote or by laying down a thick layer onto which you place the jars. Good luck. Cam yeaman@zoology.ubc.ca