Culture lids / ventilation

[Synapze]

I know that some of you use coffee filters or fabric with a rubber band to seal your cultures. Normally, I just use disposable 32oz cups with vented lids, but I've been having these strange ventilation problems that are causing my cultures to crash, so I'm trying fabric and rubber bands for the first time. Question: How the heck do you remove and replace the lids to dispense the flies without making a huge mess because of larvae and pupae sticking to the fabric/filter material?  :wacko:

 

[Jaywo]

I have hot glued the coffee filter on top of an open top mason jar. They you just unscrew it like any other jar, less messy.

 

[The Mantis Menagerie]

I know that some of you use coffee filters or fabric with a rubber band to seal your cultures. Normally, I just use disposable 32oz cups with vented lids, but I've been having these strange ventilation problems that are causing my cultures to crash, so I'm trying fabric and rubber bands for the first time. Question: How the heck do you remove and replace the lids to dispense the flies without making a huge mess because of larvae and pupae sticking to the fabric/filter material?  :wacko:

By vented, do you mean fabric-covered holes or many tiny holes? The museum were I volunteer uses fabric, and I have never seen the pupae form on the fabric. 

 

[Synapze]

By vented, do you mean fabric-covered holes or many tiny holes? The museum were I volunteer uses fabric, and I have never seen the pupae form on the fabric

The standard 32oz cup lid with multiple holes covered by fabric. The maggots migrate up to the top and onto the lid and choke off the air supply. It has been suggested that CO2 is building up due to the fabric holes being blocked, so I open all the cultures daily... unfortunately that hasn't been working. I assumed they would also form on fabric (held on by rubber bands) and make a huge mess when opening and closing. If they won't form on the fabric I should have no problem. 

It almost seems like an overproduction issue. There are so many maggots migrating that it's impossible to see through the plastic. They all migrate up to the lid and then the culture crashes. 

I have hot glued the coffee filter on top of an open top mason jar. They you just unscrew it like any other jar, less messy.

I've never used a mason jar... perhaps I should give it a try. I just figured cleanup would be very messy. I stopped recycling my cups a while back and now I just toss them. 

 

[Predatorhousepet]

It almost seems like an overproduction issue. 

Maybe it is. I culture fruit flies with the same fabric lids and do sometimes get a little migration of pupae along the edges of the lid but not even close to enough that it's blocking air flow. There are a few main reasons that overpopulation/migration might be happening: adding too many flies to start the culture and/or there is too much food in the container and/or the temperature is too high and/or there is not enough climbing material in the cup. (It could be one or several of those things in combination causing it.)

I use roughly 2 tsp of hydei, 1 tsp of melanogaster to start a culture and about an inch to an inch and a half of culture media in a deli cup (there should be very little to no food left at the end of the 30 day cycle. If there is still a lot left at the end you are either using too much or need to change to a different media.) I keep them at room temperature which is usually around 74° to 76°F but never gets higher than 78°F. Any warmer than that will make them reproduce faster. The rest of the cup should be filled with some sort of media the maggots can pupate on. I mainly use excelsior aspen shavings which I roll into a ball and sink into the media. The top of the excelsior is about 2 cm from the lid and is loose enough that the flies can crawl all through it but dense enough that they have maximum surface area to pupate. I have also use rolled cardboard and coffee filters with some success when I ran out of excelsior. They should fill most of the empty space in the cup but still have some clearance from the lid.

 

[Synapze]

There are a few main reasons that overpopulation/migr might be happening: adding too many flies to start the culture and/or there is too much food

I'll try using fewer flies when starting the culture, it just takes them so darn long to get one going with a smaller population. My fruit fly culturing skills have always been hit and miss. I either have so many that I have to dispose of them or barely enough to get by. 

 

[Predatorhousepet]

(I accidentally hit 'Submit' mid-post and you replied before I was done editing so you didn't get the full advice, lol.)

It might not be how many flies used to start the culture, especially if less makes it take really long to get started. It could be any of the reasons I listed or a combination of them. 

 

[Synapze]

I keep them at room temperature which is usually around 74° to 76°F but never gets higher than 78°F. Any warmer than that will make them reproduce faster.

My fly cabinet averages ≈ 80° this time of year. Now that I think about it, the problem has increased since winter when it probably averaged around 70-76°.

The top of the excelsior is about 2 cm from the lid and is loose enough that the flies can crawl all through it but dense enough that they have maximum surface area to pupate. 

I haven't been using that much excelsior. I've only been putting in enough to go a little over halfway up in the cup. I'm going to try that on my next batch of cultures. I don't usually pack it in because I thought they might need just a little clearance. Should my excelsior touch the sides of the cup? Perhaps I haven't been putting in enough and they don't have enough surface area. Lack of sufficient surface area and elevated temperature may be part of the problem. 

 

[Predatorhousepet]

Sounds like a plan. Lowering the temperature about 5 degrees will probably help as will adding more excelsior. When I put in excelsior it touches.all the sides of the cup and up to 2 cm below the lid. I do pack it fairly densely to give them more surface area but make sure it's loose enough that they still crawl through the holes without trouble. I'd show a pic of how I do mine but I just ran out of excelsior and have been making do with cardboard until more comes in the mail. I did find some pics for reference online. For example, this culture doesn't have enough excelsior but has too much medium:

This one is too densely packed and doesn't have enough medium:

And like Goldilocks & the three bears, these next two are just about right, ideally you want somewhere in between them for ideal excelsior density & amount of culture media: