# Fruit fly culture slowdown



## GregF (Sep 13, 2009)

I'm having an issue with my fruit fly cultures, and looking for any advice...

I have several cultures of both hydei and melano's, and suddenly, they are not producing as much as they used to. I used to get several hundred flies per day, per culture, but now...not so much.

I'm using a "potato flake"-based mix, which hasn't changed. But for some reason, I'll start a new culture, and everything seems to go as expected. I'll create the media, add flies, and then wait. Then I see the larvae, and then pupae, and then I'll have a single explosion of adults. And then things slow down to a crawl.

As far as I know, I'm doing everything the same. The same mix, same location, same temperature (79 degrees). I don't see any evidence of mites, either.

The only thing that is different is that I'm running a ceiling fan a lot more than I used to. Could that cause problems? The media doesn't "feel" dry...but could it be thickening to a point where it's not productive? Also, could the pupae be drying out before they emerge?

I would be grateful for any advice. Thank you, in advance.

Greg


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## Jadenkisses (Jun 9, 2010)

I would maybe try keeping them in warmer temps. 
I keep mine at 85 degrees, and they are exploding at a constant rate. I've been having to make cultures everyday. I have way too many for my frogs to eat, so I'm actually trying to sell some.
PM me if you need a few cultures to hold you over, if you want.
- Jade


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## Marc (Feb 3, 2008)

Just a thought. Could the adult fruit fllies be getting old. As in, after so many generations they are now pooping out and losing their vitality?

How many generations can they go through?

As I said, just a thought.


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## Ed (Sep 19, 2004)

I have a couple of possible thoughts on this..

1) the media is becoming exhausted..

2) the flies are genetically intolerant of the older culture (which happens when new cultures are only set up from the first emergence..)

3) you are between major emergence cycles

So how long has the culture been set up? 

Ed


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## chesney (Jan 18, 2007)

Last fall I was having the same problem. I contacted Josh from Josh's frogs to order more flies and told him of my problem. He suggested that I put my ff containers in a clear sterilite container and add a humidifier on the floor next to them. I did and have had excellent production since. Hope this helps


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## GregF (Sep 13, 2009)

Ed,

For example, I have a melano culture that I started on 6/29/2010. Everything went as expected, and I had a bloom of new fruit flies by 7/5/2010. So, I had a bloom over the course of 1 week, and then not much over the next 10 days.

I'm looking at the culture right now, and I can see plenty of the really small, 1st instar larvae barely above the surface of the media. I'm just not seeing the 3rd instar larvae rising to pupate.

In some of these cultures, I do see quite a few larvae that decide to pupate right at the surface of the media, or just below it. Is it possible that they are collecting there, forming a barrier?

I guess, based on what you said, that I'm getting the first "emergence", and then just a trickle after that.

Greg


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## GregF (Sep 13, 2009)

I'm including a picture, so you can see what I mean. Note that there are plenty of the "smaller" larvae, just not many of the big ones. And the "layer" of larvae collected at the media surface.


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## GregF (Sep 13, 2009)

I'm sorry about the huge photos...I thought Imgur would have resized them to something reasonable.


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## Ed (Sep 19, 2004)

GregF said:


> Ed,
> 
> For example, I have a melano culture that I started on 6/29/2010. Everything went as expected, and I had a bloom of new fruit flies by 7/5/2010. So, I had a bloom over the course of 1 week, and then not much over the next 10 days.
> 
> ...


You are between emergences. That is why the numbers have decreased. In most cultures, you will see "pulses" of emergences as groups emerge in mass, lay eggs and then are fed out or die. Inbetween you get stragglers emerging which causes a steady but much lower emergences. 
One of the easiest ways to get around this is to make cultures twice a week. This way you will have offset the times when they emerge. 

Ed


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## GregF (Sep 13, 2009)

That makes sense. Could this also be caused by me "feeding-off" too many flies from the first emergence? Would it help if I didn't start taking them out for a few days, and then leave more to propagate?

Funny thing is that I have not had this problem before, although admittedly, I'm using more flies than I was a year ago, so it's possible that I'm feeding too many off.

Before, it seemed that the larva would crawl all the way up the side of the container to pupate. They were everywhere. Now they only crawl about halfway up, and many pupate right at the media surface. Any issues there?


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## Alpha Pro Breeders (Oct 13, 2008)

Your using very little media (I use at least twice as much as you are) Might have something to do with the lack of production after your initial boom.


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## Ed (Sep 19, 2004)

GregF said:


> That makes sense. Could this also be caused by me "feeding-off" too many flies from the first emergence? Would it help if I didn't start taking them out for a few days, and then leave more to propagate?
> 
> Funny thing is that I have not had this problem before, although admittedly, I'm using more flies than I was a year ago, so it's possible that I'm feeding too many off.
> 
> Before, it seemed that the larva would crawl all the way up the side of the container to pupate. They were everywhere. Now they only crawl about halfway up, and many pupate right at the media surface. Any issues there?


It isn't going to change that as much. Setting up cultures on different dates is a better method. 

The difference in pupation levels is due to differences in moisture/humidity in the cultures. 

Ed


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## carola1155 (Sep 10, 2007)

As Ed said, the pupation levels is definitely a result of moisture. I had the same problem and solved it by doing what Chesney already suggested... put them in an enclosed container that maintains a higher humidity level than your room. You are most likely running air conditioning right now which will suck out what little moisture you had in the air already.

I do have one caveat to offer though... When I switched my cultures to a more humid environment I experienced a huge mite boom. It may have been unrelated but they literally took over the whole container the cultures were in. So if you decided to do this make sure you are prepared with some sort of anti-mite product.


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## GregF (Sep 13, 2009)

Thank you all for the information. I'll try staggering my cultures, as Ed suggested. I'd be surprised if humidity were the issue, as I live in South Texas. I'll let you know what I find out.

Thanks again,
Greg


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## Freeradical53 (Jan 25, 2008)

I need an answer here also. I am trying to master this FF thing before I have to have them. I am feeding a clown frog and the tetras in my aquarium. I make a new culture about every two weeks or so. The pupae in each only reach up about 2" from the surface. It seems that the media dries out a bit and it is difficult for the mags to go any further. What causes the tension of the climb? How do you keep the sides moist without crashing the culture?


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## GregF (Sep 13, 2009)

I think I finally figured out part of my problem. Over time, I've been using more and more vinegar in my culture mix. I'm not sure why...maybe I heard once that hydei's like more vinegar. Anyhow, I tried something different. Specifically, using less liquid, and less vinegar, and got some really amazing results.

For what it's worth, I'm using the recipe that I got from FlyCafe, which calls for 9 parts water/1 part vinegar, with a splash of unfiltered wheat beer, for the liquid. Also, I partially covered the lid to the container, to help protect it from drying out.

Before, I had a group of larvae that would only crawl about halfway up the side of the container. Now they are everywhere. On the underside of the lid, even. Hopefully, this will also solve the "emergence" problem, too.

I have a question for anyone who knows...

Does anyone know what influences "where" the larvae crawl? It seems that I get a lot of them on the side of the container that faces away from the overhead light. Are they photophobic?


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## Allyn Loring (Sep 30, 2008)

I have found after the initial bloom and feed I will let them "rest" for a day or two then ration them off depending on what I can visually see left for flies and larvae .


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## GregF (Sep 13, 2009)

Ed, I do have a question. 

When you say "first emergence", are you referring to the F1's, or simply the "earliest" pupae to hatch? If the flies were hatching continuously, which is what I've seen until now, at what point would you consider the "first emergence" to be over? Should I wait a full week after the first few emerge before I use any to propagate, or should I wait longer?

Greg


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## joshsfrogs (May 6, 2004)

Low humidity...if the pupae aren't reaching very high you need to use more water and/or keep them from drying out

Sent from my Droid using Tapatalk


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## GregF (Sep 13, 2009)

I was wondering about that. I've recently increased my ceiling fan speed, and was afraid that they were drying out. The pupae seem to be darker than before. On my newer cultures, I've mostly covered the top of the lid with a drink coaster, leaving a little bit of space for air exchange. The inside seems more damp, the larvae are climbing higher to pupate, and the pupae are much lighter colored. I'm hoping that I'm getting out of the weeds.

If I hadn't had so many cultures, I'd be seriously hurting for flies.


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## Ed (Sep 19, 2004)

GregF said:


> Ed, I do have a question.
> 
> When you say "first emergence", are you referring to the F1's, or simply the "earliest" pupae to hatch? If the flies were hatching continuously, which is what I've seen until now, at what point would you consider the "first emergence" to be over? Should I wait a full week after the first few emerge before I use any to propagate, or should I wait longer?
> 
> Greg


You should be seeing a small number emerging with a large emergence within a couple of days. That is what I am referring. There should be a small but relatively steady emergence punctated with major emergences. 

Ed


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