Flies dying?

[papilio]

Rather than chopped-up roaches, I like to use D. Melanogaster wingless flies from Flygrower's Supply for my smallest slings, until they are large enough to eat live roach babies.

But, having ordered 3 cups of flies (500 count), each time the entire population has bit by bit died in about two or three weeks. Kept at normal room temps and humidity. ... so, back to slicing and dicing!

Anyone else have this problem, and more importantly, any ideas as to what I'm doing wrong? Thanks!

 

[Nerri1029]

Rather than chopped-up roaches, I like to use D. Melanogaster wingless flies from Flygrower's Supply for my smallest slings, until they are large enough to eat live roach babies.

But, having ordered 3 cups of flies (500 count), each time the entire population has bit by bit died in about two or three weeks. Kept at normal room temps and humidity. ... so, back to slicing and dicing!

Anyone else have this problem, and more importantly, any ideas as to what I'm doing wrong? Thanks!

http://www.woodrow.org/teachers/bi/1994/life_cycle.html

I would imagine some are reaching the end of their lifespan.
Assuming you are getting them as adults.

Maybe it's something else.. but maybe not.

 

[papilio]

Thanks Nerri,

That is of course possible, though they say to throw out the culture and replace it with fresh after two months. So it seems expected that they'll live longer. Plus there are plenty of squirming larvae and pupae at first, but the larvae seem to die off too -- perhaps just a bit later -- and none of the pupae emerge, far as I can tell. A good friend also uses the same flies, and says there is always a nearly full cup of flies as time goes by, they reproduce so quickly. Hmm ...

 

[Nerri1029]

Thanks Nerri,

That is of course possible, though they say to throw out the culture and replace it with fresh after two months. So it seems expected that they'll live longer. Plus there are plenty of squirming larvae and pupae at first, but the larvae seem to die off too -- perhaps just a bit later -- and none of the pupae emerge, far as I can tell. A good friend also uses the same flies, and says there is always a nearly full cup of flies as time goes by, they reproduce so quickly. Hmm ...

That evidenec supports something you are doing.
get details about how your friend keeps them.

Try and replicate that method, even down to using the same water etc.

 

[elportoed]

I think the food in the old culture would go bad or run out, so you'd have to start new ones every few weeks. I don't think a culture would last forever, 2-3 weeks at best.


http://www.amphibiancare.com/frogs/articles/fruitflies.html

 

[papilio]

Thanks elportoed,

You have hit on one of the solutions! And thanks for the link!!!

There I found excellent and comprehensive instructions, completely ignored by my supplier. Some rules for success are ...

• Make a fresh culture every week, and don't let it dry out.
• Mold on the culture medium is common and deadly.
• Too many flies in the culture can kill the entire population (!). Like, several dozen, NOT 500 !!
• Make an additional culture each time the population in the previous one gets too high, and/or about every two weeks, the life-cycle of the flies. Having a dozen cultures going at once seems common. Currently I have about a dozen slings requiring flies, so I'm going to need a lot of cultures going at once!!
• Don't let the culture-rooms temp fall below 70F

Thank you so much! Way more work, but apparently the keys to success.
But considering these requirements, I'm thinking I'll stick with the mutilated roaches, as it seems to be working well.

 

[papilio]

That evidenec supports something you are doing.
get details about how your friend keeps them.

Try and replicate that method, even down to using the same water etc.

Thanks again Nerri!

According to her, we are both doing the same thing, just totally leaving them alone except when capturing when needed -- in other words, doing nothing! And still she's getting very adequate results. Still, there must be some unknown difference somewhere in each of our "methods", you are right. (It seems we do both have the same water in the culture,as it is pre-made, from the same supplier. But good advice!)

 

[RoachGirlRen]

Just to add, a very common COD for these guys is a lack of b vitamins, which can be provided by adding a few grains of yeast, or by a couple of drops of an oral b12 supplement, at the surface each time you make new media.

 

[Bill S]

My first thought is that you might need to use a different media. I used to make my own from a recipe I found online - and I was not happy with the results. I now use a medium that I buy from one of the sites that caters to Dendrobatid frog hobbyists, and I get much better results.

Make a fresh culture every week, and don't let it dry out.

I run about six bottles of each species of fruit fly - changing one of those six each week. That means that each bottle only gets changed every six weeks - and that seems to work quite well. And it also means that at least one or two bottles are producing at their peak at any given time. If you change all your bottles at once you will have limited numbers of adults all the time.

(Note - in actual practice, if the cultures are producing heavily the media may get replaced more frequently just because it gets used up. But sometimes I take a short-cut and just add a spoonful of media to an existing culture to hold it over until I have time to change it out.)

Mold on the culture medium is common and deadly.

Commercial media generally have mold inhibitors added to them, and I do no have mold problems in the cultures I raise.

Too many flies in the culture can kill the entire population (!). Like, several dozen, NOT 500 !!

A good melanogaster culture will produce swarms of flies. I haven't had crashes due to this - probably because I put plenty of the medium in each bottle to feed the large numbers of larvae.

Make an additional culture each time the population in the previous one gets too high, and/or about every two weeks, the life-cycle of the flies. Having a dozen cultures going at once seems common. Currently I have about a dozen slings requiring flies, so I'm going to need a lot of cultures going at once!!

Yup - having a bunch of staggered cultures is a good idea. A dozen might be a lot - but that depends on how many you are feeding out. At the moment my wife has about three dozen spiders that eat fruit flies of various sizes, and we've got six bottles of melanogaster and six or hydei easily handling that load.

Don't let the culture-rooms temp fall below 70F

This makes a big difference with D. hydei - much lower production below 70F. D. melanogaster seems to do well in the 60s.

One other thought - make sure the medium doesn't dry out or get too wet. Either extreme will impact production.

 

[papilio]

Hi Bill, Thank you very much for the amount of thought you put into this!

If it's as simple as changing the media (and the other things you said to include in the method -- not all that much), that would be great! The instructions I came across earlier this evening sound intelligent enough, and the reasoning seems to make sense -- but I've got plenty of work already with the Ts and roaches to fill more of my free time than I'd like. (Though, like all of us, I'm loving it -- otherwise, what's the point? )

Bill, do you suppose you could PM me with the media supplier which you mentioned? Thanks.

Still so weird that my friend is having no problems -- she just gets the things in the mail, let's them just sit on a shelf till she needs some, and says that with the quick life-cycles the cup keeps producing flies for a very long time. (She is, BTW, as honest a person as you'd ever find, so no factor there.) Yeah, I'm gonna have to grill her on exactly what she's doing!



*** One thing just occurred to me -- what about air quality? In my apartment my next door neighbor smokes, and of course I can smell it, and wish he didn't, but beyond being noticeable it is by no means a strong pollutant to the air in my place. Thoughts on this?
__________________

One more unrelated question ... even my very tiny first instar slings could, it looks to me, handle much larger flies than the D. melanogaster, I'm guessing they'd easily need several for a satisfying meal. Are they in fact big enough, or should I switch to D. hydei for all my slings?

Here's a pic of my smallest sling at the moment, have never had anything smaller than this, a N. coloratovillosus. Well, okay, when we're talking of something as miniscule as this, a couple of D. Melanogasters would probably satisfy the appetite -- but I've got lots more still needing to eat flies, but they're several times this size.

 

[biomarine2000]

I think the food in the old culture would go bad or run out, so you'd have to start new ones every few weeks. I don't think a culture would last forever, 2-3 weeks at best.


http://www.amphibiancare.com/frogs/articles/fruitflies.html

Thank you elportoed for this info. I have been wanting to make my own culture and now know how. Also thanks to everyone else who provided information. This thread answered a lot of my questions.

 

[Bill S]

Bill, do you suppose you could PM me with the media supplier which you mentioned? Thanks.

PM will be on its way right after this message gets posted.

Still so weird that my friend is having no problems -- she just gets the things in the mail, let's them just sit on a shelf till she needs some, and says that with the quick life-cycles the cup keeps producing flies for a very long time. (She is, BTW, as honest a person as you'd ever find, so no factor there.) Yeah, I'm gonna have to grill her on exactly what she's doing!

It might also be the conditions she is doing it under rather than what she is doing. For example, the temperatures she keeps her house at, the humidity level of her house, etc. Maybe even the light levels where she keeps her fly cultures. (I've never heard of light levels being important - but who knows?) I do know that we had some problem with media drying out too fast (I live in the desert, so that's not a big surprise), so I modified the lids to the container to allow less ventilation.

*** One thing just occurred to me -- what about air quality? In my apartment my next door neighbor smokes, and of course I can smell it, and wish he didn't, but beyond being noticeable it is by no means a strong pollutant to the air in my place. Thoughts on this?

Nicotine is a powerful insecticide - we used to use it as the primary means of aphid control in a greenhouse complex where I worked many years ago. But I doubt you're getting enough nicotine from your neighbors to have an impact. I'd bet on humidity or temperature differences being the cause of your problems.

 

[Bill S]

Just to add, a very common COD for these guys is a lack of b vitamins, which can be provided by adding a few grains of yeast, or by a couple of drops of an oral b12 supplement, at the surface each time you make new media.

A good point - with an exception. Yeast is an excellent source of B-complex vitamins, with the exception of B-12. No B-12 in yeast. Since B-12 is not produced by plants, it's possibly of little value to fruit flies. But D. melaongaster feeds on yeast, and it's a very good idea to "prime" your culture media with a small dash of yeast. A couple points to remember - if you cook your media, do not add the yeast until the media has cooled to room temperature or you will kill it. Also, do not use a killed yeast - you want a live yeast culture growing in the jar. And apply it sparingly - a tiny bit of yeast will grow quickly and will provide all the yeast you need for your flies.

The company I buy my fruit fly media from uses a different recipe for D. hydei than for D. melanogaster. They also recommend a dash of yeast for melanogaster but not for hydei. I don't know what the difference is, but the results are clear.

 

[RoachGirlRen]

Oye, thanks for the correction - that was a mis-type on my part. Should have said an oral b vitamin/b complex supplement; I'm used to giving nutrition advice to other vegans so b12 is always on my mind.

 

[Bill S]

I'm used to giving nutrition advice to other vegans so b12 is always on my mind.

Yup, for vegans this is an important issue. It would be interesting to know how fruit flies cope without it though. Maybe they can manufacture it in their bodies?

The aspect of fruit fly nutrition might be significant for tarantulas. I've heard of some reports of animals fed exclusively on fruit flies having difficulty in molting, and wonder if that might have something to do with fruit flies being raised on inferior media. We've raised generations of spiders on fruit flies grown on high quality media without seeing such problems.