# How long are you waiting to make cultures from a fresh hatch



## *GREASER* (Apr 11, 2004)

The recomended time I heard to wait after the first hatch of ffs in a culture has bloomed to make new cultures is 9 days. To make sure that both Ms and Fs are represented in the cultures. I cant remember what sex pops out first. I was wondering if anyone waits this long.


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## devin mac (Oct 4, 2004)

i'm generaly tossing flies into the new cultures as soon as i notice there are a lot more in there than what i originally put in.  could be a couple days, could be more. i'm not very exact, but i always have way more flies than i can handle.


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## Scott (Feb 17, 2004)

I am extremely systematic in the way I do fruit fly cultures. Everyone really should be.

I have 2 weeks worth of cultures "growing" at all times plus. So that really means at the end of the 3rd week I make new cultures from a batch - then start feeding them out.

s


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## devin mac (Oct 4, 2004)

i know i _should_ be more systematic about it, but i failed miserably at it. i'm definately good at keeping tons of flies on hand, though.


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## ChrisMc (Mar 7, 2004)

I think the females hatch before the males but not by a difference of more than one day.


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## NCSUdart (Oct 1, 2004)

i'm not sure about the sexes hatching at different times. all i remember from working with fruit flies in my genetics lab is that the females will stay virgins for the first 6 hours so it is important to set up new cultures for the purposes of determining allele dominance, frequency, etc within 6 hours of parental generation hatching. or separate males from females within that time.


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## *GREASER* (Apr 11, 2004)

Yeah I brought this up becuase the 9 day mark seemed really long to me to get a good sex ratio out of the flys. It just didnt seem right.


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## rozdaboff (Feb 27, 2005)

I thought the 9 day figure was for hydei only...


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## elmoisfive (Dec 31, 2004)

I have a system very similar to Scott's that I basically figured out by trial and error - no big insight on my part but I've found that being systematic has improved and smoothed my food supply situation vis-a-vis FFs. Plus since I'm up to making 40 new cultures per week I find that unless I have a schedule, it's easy to get off track.

Bill


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## benmz (Feb 18, 2004)

Waiting 9 days seems excessive to me for either species. You would only need a few males to fertilize larger numbers of females. Also once the females are fertilized, they start laying/dropping eggs. It would be better for them to drop eggs into a nice new medium as opposed to one that is being used up, molded and getting old in general.

Hydei flies live a long time, usually very few of the parent flies die. So when the new, young verile flies emerge there are plenty of males around to do the deed necessary even if only females emerge first for the first few hours or a day or so. This should increase production since you have now started a new culture ASAP and the period between cultures producing flies for feeding is reduced. Of course this is just my opinion.

My biggest problem is temps and humidity. It is very hard to control (for me anyway) so that they are consistent. I'm sure many of us have seasonal differences in production. Lower winter temps and humidity slow production drastically and I try to make it up with larger numbers of cultures, but it's still difficult.

-Ben


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## Scott (Feb 17, 2004)

Ben,

As you say, it's much drier in wintertime.

I just spray the cultures at about the 10 day mark. I probably end up spraying them a couple of times over the life of the culture.

But I'm also on the fly "schedule" noted above.

s


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