How do I safely store oothecae in the fridge?

[Pudge Toad]

I was wondering how I could store oothecae in the fridge without them drying out. I had some last year that seemed to have dried out and died in the fridge. They were Chinese mantids, as are the ones I am trying to store this winter. I would leave them outside but the winters are too cold for Chinese mantids. Should I mist them in the fridge or will that cause mold? If so, how often should I mist?

 

[CosbyArt]

The problem with putting ooths in the fridge is that they need to be put in soon after laid and are dried naturally for best success; otherwise, the eggs start to develop and all the fridge will do is kill the ooth eggs. I've put many of my pet's ooths, and wild collected ooths, in the fridge with a high hatch rate (the few duds were likely unfertilized ooths as they were the wild collected ones).

I keep my insect mini fridge set to 37F and leave them in there for a minimum of 2 months, it has been said they will keep 4 months longer in the fridge than in the wild, so that means you can leave them in there for about 10 months before the hatch rate takes a large nosedive.

I put each ooth in it's own 2oz container with lid (the little condiment/souffle cups) and poke one hole in the middle of the lid for air exchange with a needle. I then label the cups with the species, date laid, and the date they are placed in the fridge. I usually stack the cups 5 high as they fit nicely in the bottom of my fridge, and the hole appears covered but isn't truly. My fridge also houses carrots, lettuce, and other goodies for my various pets in there, so there is always humidity from the veggies in the refrigerator and prevents the ooths from drying out (and makes adding water needless).

If you think you have to add water (most keepers don't, myself included) add a single drop of water to the container itself (Orin's method, from memory though as I can't find the post). You do not want to mist the container or ooth as it will cause mold/fungus/bacterial growth and in time can soften the ooth itself ruining the eggs inside. With the single drop of water let it sit in the container refrigerated for 24hours - if the drop is evaporated add another drop, or if it is still there remove it with a tissue (humidity is too high). Then repeat. If you see mold growth rub with a damp towel very gently to remove the mold, if necessary add a drop of bleach to a cup of water and use that.

For me personally I find letting things happen naturally is better than trying to add water as it tends to cause mold. One method that will help with the humidity though is to simply place a small bowl of water on the fridge shelf. The water will slowly evaporate and because the ooths container lid has a hole, the humidity will reach the ooth. Again though, if the humidity becomes too high it can lead to mold.

Here's a interesting article I did find on the diapause process itself.

 

[Pudge Toad]

Thanks so much, this information is very helpful! 

 

[CosbyArt]

Your welcome, and best of luck with this batch of ooths.

 

[Krissim Klaw]

Good stuff

You know this was one of the nicest/most detailed posts I've seen in response to someone asking how to overwinter mantises in a fridge. Usually the responses people give on this topic are rather vague and it is refreshing to see someone taking the time to go into specifics, especially on achieving proper humidity, which is the way us keepers tend to screw things up when it comes to oothecae care.

 

[CosbyArt]

You know this was one of the nicest/most detailed posts I've seen in response to someone asking how to overwinter mantises in a fridge. Usually the responses people give on this topic are rather vague and it is refreshing to see someone taking the time to go into specifics, especially on achieving proper humidity, which is the way us keepers tend to screw things up when it comes to oothecae care.

Thanks for the kind response. I know when I first started I kept asking everyone every little step about it when my first mantis was laying ooths, and spent many hours trying to find more information online. In the end the only way I learned more than "throw them in the fridge", or "they don't need it and will do better without it" was from experience so I thought I'd share.

A interesting note about ooths that do naturally diapause, such as my local species Carolina mantis (Stagmomantis carolina) and Chinese mantis (Tenodera sinensis) is if they are kept warm and allowed to hatch without a cooling period they take 70-90 days to hatch and do it in small amounts of nymphs daily for a week. If they were kept in a fridge at least 2 months, they hatch in about 30-40 days and tend to do one big hatch - at least from the ooths I've hatch on average.

 

[Krissim Klaw]

Thanks for the kind response. I know when I first started I kept asking everyone every little step about it when my first mantis was laying ooths, and spent many hours trying to find more information online. In the end the only way I learned more than "throw them in the fridge", or "they don't need it and will do better without it" was from experience so I thought I'd share.

A interesting note about ooths that do naturally diapause, such as my local species Carolina mantis (Stagmomantis carolina) and Chinese mantis (Tenodera sinensis) is if they are kept warm and allowed to hatch without a cooling period they take 70-90 days to hatch and do it in small amounts of nymphs daily for a week. If they were kept in a fridge at least 2 months, they hatch in about 30-40 days and tend to do one big hatch - at least from the ooths I've hatch on average.

Your post actually came at a perfect time since I've been thinking about overwintering some oothecae for the first time. I've heard similar things about the Carolina mantis ooths so I thought it would be fun to try some in the fridge and let the others just hatch out and see how it effects their hatch times and such.

 

[CosbyArt]

Your post actually came at a perfect time since I've been thinking about overwintering some oothecae for the first time. I've heard similar things about the Carolina mantis ooths so I thought it would be fun to try some in the fridge and let the others just hatch out and see how it effects their hatch times and such.

Glad it perked your interests, best of luck with your ooths. I've done several the last couple of years and it seems to remain about the same for me. After you do yours though post your results, I'd like to see how much it varies for other keepers.

If you collect ooths in the wild, and they happen to be infected with parasitic wasps, the wasps hatch about 15 days before the mantises do (so that should be plenty of time to freeze or squish the wasps). A ooth even if infected with the parasitic wasps will still hatch some mantis nymphs; although, the number of mantises will be usually about half (about 10 Carolina nymphs) and sometimes less.

In my area the wasps tend to show up on average in 1 ooth out of about 15, but some seasons and areas it has been even worse.

 

[Krissim Klaw]

In my area the wasps tend to show up on average in 1 ooth out of about 15, but some seasons and areas it has been even worse.

Nice info on the wasps. I've yet to run in to any but I don't hatch out that many wild ooths. The current ooths I am planning to incubate are all from my girl so they should be pretty clean. Is there a certain time-frame range you have found is good to wait before putting a freshly laid ootheca in the fridge?

 

[CosbyArt]

Nice info on the wasps. I've yet to run in to any but I don't hatch out that many wild ooths. The current ooths I am planning to incubate are all from my girl so they should be pretty clean. Is there a certain time-frame range you have found is good to wait before putting a freshly laid ootheca in the fridge?

I find anywhere from about 2 days up to a few weeks is fine, but the sooner they go in the better they tend to do (the hatching nymphs later on that is - hardiness/strength wise). I prefer to let the ooths harden fully for a few days (2 to 3) and if I plan to diapause in the fridge, in they go.

In nature such ooths will often sit up to 1 1/2 months before the temperatures outside start to drop into the 40's F degrees mark or lower, at least in my area. During that time outside the overnight lows are continuing to lower though from the 60's F typically, so that is likely why they are fine; however, placing ooths in the fridge that have been at room temperature for that length of time will result in few hatching nymphs.

 

[Krissim Klaw]

I find anywhere from about 2 days up to a few weeks is fine, but the sooner they go in the better they tend to do (the hatching nymphs later on that is - hardiness/strength wise). I prefer to let the ooths harden fully for a few days (2 to 3) and if I plan to diapause in the fridge, in they go.

In nature such ooths will often sit up to 1 1/2 months before the temperatures outside start to drop into the 40's F degrees mark or lower, at least in my area. During that time outside the overnight lows are continuing to lower though from the 60's F typically, so that is likely why they are fine; however, placing ooths in the fridge that have been at room temperature for that length of time will result in few hatching nymphs.

Sounds good. Thanks for the info. I'll let you know how the hatching ends up going. =3

 

[CosbyArt]

Sounds good. Thanks for the info. I'll let you know how the hatching ends up going. =3

Your welcome, and thanks.