# Large scale fruit fly workflow



## Toadsworth (Sep 16, 2012)

I'm looking to improve the workflow (for lack of a better word) of our fruit flies at work. I would very much appreciate some input from others who has many fruit flies cultures.

I work at a zoo, and the number of animals and species may vary some, but not much. At the time there are six vivariums where we feed fruit flies. First a group of _D. tinctorius_ (around 5), next a group of _D. leucomelas_ (around 10), a group of _E. tricolor_ (around 10-15), a group of _P. klemmeri_ (around 10), a pair of _L. williamsi_, and lastly a group of microgecko (around 10).

The way the fruit flies are managed now we start around 9 new cultures (550ml cups) two times a week, so 18 each week, which might be excessive? We throw them out after about a month.

I recently started taking care of these, about a month ago, and now I am having a problem I did not think I would have.. I'm having too many flies. I was away for a week, and now I'm struggling with trying to feed them away and wondering which of the cultures to use first, in some of them there are already a lot of dead flies, so feeding becomes a hassle.

I like my stuff organized, and the lack of experience with large amounts of fruit flies makes me unable to make a good system on how to manage the cultures. That's why I need some input, so I'm throwing out a few questions that has come up the last couple of days trying to salvage it.

When should I feed out the flies from newly started cultures? I'm guessing the flies are also eating the medium, as I'm seeing there is a lot less in the cultures with too many flies, so I'm thinking get the flies out as soon as they have done their job? With this many cultures, in this kind of setup, keeping mites away is near impossible, but I'm guessing it is okay as long as the cultures are thrown out after a month, it does not look like the mites are taking over completely. How many cultures do you guys have/would have a group of animals this size? There can be some temperature issues in the summer, so I think that is why we have so many cultures, but the last few weeks the temperature has been low, so that is probably why there are so many flies.

I think that's it for now, more questions will probably come. I hope someone can help, I'm interested in any kind of input.


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## aspidites73 (Oct 2, 2012)

Personally, I make cultures once a week as a rule. I adjust my culture numbers, accordingly. I found a similar problem to yours when I made twice a week cultures. I try to let the cultures run low towards the end of the week, even if that means 'wasting' some flies. If kept uncrowded you should get a boom every 3-5 days once mature. I keep my newest cultures less populated than my mature cultures. The first emergence is genetically intolerant to overcrowding. As such, don't use fresh matured cultures to populate new cultures. You will isolate the genes for population intolerance and get a lot of dead flies in a booming culture. I, too, discard cultures after a month.


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## chillplants (Jul 14, 2008)

That many cultures seems a bit excessive. I do 2 cultures a week for 10 frogs (2 tanks - 5 auratus, 5 variablis) and I usually have plenty of extras when I toss them at the end of the month cycle. With this ratio in mind, you could probably cut back to 10-ish cultures once per week or maybe 5-6 cultures twice a week just to keep them as fresh as possible.

Edit: I was just thinking that maybe the zoo makes so many to ensure they never run out in the event of a culture crash.


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## 55105 (Jan 27, 2015)

chillplants said:


> That many cultures seems a bit excessive. I do 2 cultures a week for 10 frogs (2 tanks - 5 auratus, 5 variablis) and I usually have plenty of extras when I toss them at the end of the month cycle. With this ratio in mind, you could probably cut back to 10-ish cultures once per week or maybe 5-6 cultures twice a week just to keep them as fresh as possible.
> 
> Edit: I was just thinking that maybe the zoo makes so many to ensure they never run out in the event of a culture crash.


In my experience overcrowded cultures always leads to a crash and/or under-productive cultures.

10 per week should be plenty for 50 frogs. Hopefully someone with a large collection can offer some advice. 

I only keep 13 frogs and only make 2 D. melanogaster cultures once a week and 1 D. hydei every other week. I always have too many. If I have any issues I don't worry two much because I know in about a week I'll have plenty of flies again.


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## Alan (Jan 12, 2005)

I approach it from a calendar perspective. I know the number of days Melos and Hydei take to start producing - and to peak.

I start cultures most days - about 18-20 a week. I pre-mix one big batch and put them in FF cups. Then I pull a few pre-mixed cups each day for seeding.

I want cultures peaking every day or every other day. Realize that breeding takes place in the cup after the initial few days - so culture production continues until it burns out.

You have to develop a tempo for seeding that meets your feeding needs and works in your temperature and humidy range - and with your mix. Those are variables - including how many flies you seed in a cup.


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## Ed (Sep 19, 2004)

port_plz said:


> In my experience overcrowded cultures always leads to a crash and/or under-productive cultures..


This is generally due to the genetics of your flies. Flies that are not selected for tolerance of crowded conditions perform exactly as you describe. 

The larvae can even digest and feed on the chitin from the pupae and deceased flies so its not a food limitation issue. 

Some comments 

Ed


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## 55105 (Jan 27, 2015)

Alan said:


> I want cultures peaking every day or every other day. Realize that breeding takes place in the cup after the initial few days - so culture production continues until it burns out.


So they're probably making cultures 2x a week to spread out the hatch. 

That's a really good idea! Might even be beneficial on a small scale. Mine usually peak at the same time and I have too many flies.



Ed said:


> This is generally due to the genetics of your flies. Flies that are not selected for tolerance of crowded conditions perform exactly as you describe.
> 
> The larvae can even digest and feed on the chitin from the pupae and deceased flies so its not a food limitation issue.


Ed, how can we selectively breed FFs at home? My process is to seed out of freshest cultures available and I'm very indiscriminate. I have a relatively small amount of cultures to choose from and usually avoid seeding from older cultures.

Also, I thought I read somewhere CO2 or CH4 buildup and O depletion was the main cause for crash in overcrowded cultures. But I trust your knowledge over most of the stuff I read...


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## chillplants (Jul 14, 2008)

I usually start new cultures from my 2nd and 3rd oldest cultures (a little mix of each into each new cup for a little diversity). These have had at least 2 booms and while they are not overcrowded, they are certainly full cultures. I never seed cultures from the oldest or newest.


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## Toadsworth (Sep 16, 2012)

Thanks for all the brilliant replies!

I threw away a lot of cultures yesterday, some with loads of mites, some which just looked bad. When I'm looking at the cultures I see that there may be too many larvae in the cultures, i most of them the larvae layer is about double the size of medium layer (i fill about 1/3 of the cups with medium). After seeing several people online using 50-100 flies to start a culture, I realized that I might be using too many flies. Would that cause it to be too many larvae, or will there be as many larvae as the "habitat" can sustain anyways, what effect has the number of starting flies on the culture?

Here is an example of the cultures, first one was made yesterday (using 50-100 flies), second is about two weeks old, third is about three weeks old. When they get about three to four weeks old the pupae start falling out when trying to feed, is this because it is drying out, or because something is eating up the medium too fast (flies, larvae, mites)?









Also I've been looking into using diatomaceous earth on the shelves the cultures are on, it's not enough room to keep every culture separate (using towel with rubber band as a lid, so they are touching), but as long as I keep the batches separate it should at least have an effect. Anybody have any experience in using diatomaceous earth for fruit fly cultures? The cultures are in the same small room as a tarantula collection, so how "potent" is this stuff? I'm guessing it wont be a problem, as the cultures will never be in contact with the tarantulas, and I don't think I need to worry about airborne particles that much?


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## Alan (Jan 12, 2005)

Without a close look at your cultures in hand - I have to engage in some guesswork. Some of that guessing will be incorrect.

I think you need to be able to measure temperature and humidity near your cultures - and regulate it. Pupae falling out of cultures is usually an indication that they are too dry.
What are you using as that filter paper cover? That amount of exposed area is probably leading to too dry of an environment in the cup.

If you have an issue with mites - I would clear the shelves and either take them outside and scrub and rinse them very well - or use a household cleaner to meticulously clean 100 of the shelving surfaces, supports and the floor area around it. I haven't used DE (other than the garden years ago). I would clean shelves once a week.

Don't over-seed cultures. IMO - your cultures seem (to me) to be a bit overloaded with media. I would try cutting that back 20-25%.

Humidity varies by season, geography and the weather. I need to adjust mine in my basement in the summer as Mid Atlantic humidity builds in the summer.


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## Ed (Sep 19, 2004)

Alan said:


> If you have an issue with mites - I would clear the shelves and either take them outside and scrub and rinse them very well - or use a household cleaner to meticulously clean 100 of the shelving surfaces, supports and the floor area around it. I haven't used DE (other than the garden years ago). I would clean shelves once a week.r.


Its a lot easier to simply use anti-mite paper for the shelf liner and just replace it twice a year. See Anti-Mite Paper, 18 in x 10 ft Roll | Carolina.com 

some comments 

Ed


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## Ed (Sep 19, 2004)

port_plz said:


> Ed, how can we selectively breed FFs at home? My process is to seed out of freshest cultures available and I'm very indiscriminate. I have a relatively small amount of cultures to choose from and usually avoid seeding from older cultures.



This is exactly how we can select flies at home. Your selecting flies from the first emergence only which selects not only for a faster development time but intolerance to conditions that appear as the culture ages. 

See http://darwin.bio.uci.edu/~mueller/pdf/JEvolBio00.pdf



port_plz said:


> Also, I thought I read somewhere CO2 or CH4 buildup and O depletion was the main cause for crash in overcrowded cultures. But I trust your knowledge over most of the stuff I read...


While you can crash a culture through CO2 poisoning this isn't as common if the cultures are exposed to air flow (as there is some heat generation in the media from the larval feeding and this causes some ventilation) but this has often been attributed as the cause for a very long time in the hobby which of course has ensured it is often repeatd ... Instead the intolerance is to ammonia buildup in the cultures from the protein ingested in the course of feeding. 

If you select from either the second emergence or mix the first emergence with a later emergence you will either get more booms or a much more consistent emergence over time. 

Mites regardless of the kind involved were often attributed as the cause of the crashing of cultures but unless you get a mite species that actively predates on the flies the main problem due to the mites is that they compete with the flies for the media but the conditions in the cultures often don't favor the mites until the culture is beginning to dry out. this means that the common mite infections aren't the cause of the culture crashes and again something that has been passed down in the hobby as a simple connection. 
It is simply much easier to accept the fact that there are likely to be mites in a fly culture for feeding and manage them than it is to continually try to exclude them and there are simple ways to reduce their presence such as using mite paper, try to not let cultures touch (so they have to navigate the mite paper), discard cultures about 30 days or when the cultures dry out enough production is impacted (unless you need smaller sized flies) which ever is sooner and dusting the flies before using them to seed a culture all reduce mite impacts. 

some comments 

Ed


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## brettxxx4 (Jun 16, 2013)

I tried an interesting thing one day and added some (about 1/4 cup) of dried sphagnum moss resting on top of my new culture and it increased my fruit fly production at least by two times maybe three. I'm not sure why exactly but it worked.
Brett


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## oneshot (Mar 5, 2010)

I think sports_doc makes like 60 a week. Maybe he has some tips. 

But too many is better than too few. 
And you're reusing the cups and lids?


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## Spenseriana (Sep 18, 2014)

brettxxx4 said:


> I tried an interesting thing one day and added some (about 1/4 cup) of dried sphagnum moss resting on top of my new culture and it increased my fruit fly production at least by two times maybe three. I'm not sure why exactly but it worked.
> Brett


This is really interesting to me. Does anybody else know why this is?

Two question, Brett:

1. Did it shorten the culture's life?
2. Have you repeated this in subsequent cultures with the same effect?


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## Dane (Aug 19, 2004)

oneshot said:


> I think sports_doc makes like 60 a week. Maybe he has some tips.


Seems like Harrington rarely posts anywhere other than the classified section of the forum these days, but if he did, I'm sure he could offer some good advice. I typically have 50-100 frogs at any given time (depending on offspring) and I only make 6-8 cultures/week, but I also feed several other types of insects regularly.


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## Ed (Sep 19, 2004)

Spenseriana said:


> This is really interesting to me. Does anybody else know why this is?


The problem is that this is a subjective observation, now if the person weighed all of the flies produced and compared it to that of one of the "normal" cultures it would be of value. Consider as a total example, the addition of the sphagnum did increase the number of flies but they were smaller in size resulting in a reduction in biomass production. 

This sort of effect may also be attributed to increased survival of the adults used in seeding the cultures, or even in the age and number of flies used to start the cultures. 

One of the limitations on production of flies in the cultures is the competition for better feeding sites between the larvae. Larger larvae tend to push the smaller larvae into less desirable sections of the media (the maggots secrete enzymes that predigest some of the media). 

some comments 

Ed


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## Frogs123 (Jul 10, 2016)

Diversity has always yielded better cultures. A few flies from each active culture will work best.


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## ajimenez (Apr 12, 2016)

Ed said:


> port_plz said:
> 
> 
> > In my experience overcrowded cultures always leads to a crash and/or under-productive cultures..
> ...





aspidites73 said:


> Personally, I make cultures once a week as a rule. I adjust my culture numbers, accordingly. I found a similar problem to yours when I made twice a week cultures. I try to let the cultures run low towards the end of the week, even if that means 'wasting' some flies. If kept uncrowded you should get a boom every 3-5 days once mature. I keep my newest cultures less populated than my mature cultures. The first emergence is genetically intolerant to overcrowding. As such, don't use fresh matured cultures to populate new cultures. You will isolate the genes for population intolerance and get a lot of dead flies in a booming culture. I, too, discard cultures after a month.


I found this interesting about not using the first boom to create more cultures. I will try this next go around!


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