Can someone help me figure out why one of my mantises died?

[Pearson Realize]

Can someone help me figure out why one of my mantises died?
 
I ordered a chinese mantis about a month or a month and a half ago, and they sent two. I got them out of the mail and into their setup as soon as possible, they spent almost no time outside. They’re in fruit fly cups, which are good size enough for them to move around freely but not too big for them to struggle finding prey.  
 
I’m not sure what stage they’re on, they’re both almost exactly one inch. I’ve had them for three or four weeks now, and the I’ve seen them both molt once. The other mantis seems perfectly fine. 
 
The one that died seemed slightly less active, and only had one antenna when I got him. He also actually molted on the ground as opposed to hanging somewhere. When I saw him laying on the ground I thought he was dead at first but I came back later and he was larger and his old skin was on the ground. I’m not sure if that’s useful information or not. 
 
They’re in different cups before anyone asks, I give them fruit flies about every 3 or 4 days, and I actually saw this one eat yesterday, the night before it died. I mist their cups with natural spring water every night. Both kind of have black spots on their abdomen, which I originally thought were illness or something but it seems they’re just markings. 
 
Can anyone help? I could provide pictures if need be. Trying to avoid the other one dying too. My only two concerns are that I might be misting them too often, I have a desk light to simulate day night cycles and as I said I mist them once every night. The cups they're in are not that big so I might be making it too humid. Second, the cups I got for them were given to me by someone, but the lid was used before. I'm not sure if germs spreading from one mantis to another are a big concern, but that's really the only thing I can think of. 

 

[Synapze]

He also actually molted on the ground as opposed to hanging somewhere. When I saw him laying on the ground I thought he was dead at first but I came back later and he was larger and his old skin was on the ground. I’m not sure if that’s useful information or not.

If he was on the ground freshly molted, he may have fallen. They are practically jelly when freshly molted until they dry completely. A fall during molting is usually, but not always fatal. Chinese are notorious for bad molts. 

I mist their cups with natural spring water every night.

You may want to cut back on misting. In a 32oz cup with a fabric lid, the humidity can build up too high. I suggest getting a humidity meter. They are cheap on eBay as low as 99¢. They're not lab quality, but good enough for mantids. 

Both kind of have black spots on their abdomen, which I originally thought were illness or something but it seems they’re just markings. 

You'll need to post a pic if possible.

Second, the cups I got for them were given to me by someone, but the lid was used before. I'm not sure if germs spreading from one mantis to another are a big concern, but that's really the only thing I can think of. 

A 32oz cup for a one inch mantis shouldn't be too large that they can't catch prey. How many Hydei fruit flies do you usually feed them? I've never had an issue with reusing fabric lids. It doesn't hurt to give them a good rinse and let them dry. 

Sometimes they die for no identifiable reason. So, it was probably through no fault of your own, so don't get discouraged. 

Post some pics and someone can probably help.

 

[Pearson Realize]

If he was on the ground freshly molted, he may have fallen. They are practically jelly when freshly molted until they dry completely. A fall during molting is usually, but not always fatal. Chinese are notorious for bad molts. 

You may want to cut back on misting. In a 32oz cup with a fabric lid, the humidity can build up too high. I suggest getting a humidity meter. They are cheap on eBay as low as 99¢. They're not lab quality, but good enough for mantids. 

You'll need to post a pic if possible.

A 32oz cup for a one inch mantis shouldn't be too large that they can't catch prey. How many Hydei fruit flies do you usually feed them? I've never had an issue with reusing fabric lids. It doesn't hurt to give them a good rince and let them dry. 

Sometimes they die for no identifiable reason. So, it was probably through no fault of your own, so don't get discouraged. 

Post some pics and someone can probably help.

The first pic is the currently living mantis, the second is the dead one. And, sorry if I wasn't clear, the first time I saw the mantis molt it was on the ground. It survived that molt though, and I'm not sure if it was trying to molt when it died or not. I usually give them about 4 or 5 fruit flies, partly because I'm not aware of a good method to really feed them fruit flies other than tapping the fruit fly jar over the cage and hoping a proper amount falls out.

 

[Synapze]

And, sorry if I wasn't clear, the first time I saw the mantis molt it was on the ground. It survived that molt though, and I'm not sure if it was trying to molt when it died or not.

How long had it been since his last molt? Was he still able to climb up to a good molting surface. Almost all of mine that I keep in 32oz cups usually molt from the lid. 

How often do you feed them? 

 

[Pearson Realize]

How long had it been since his last molt? Was he still able to climb up to a good molting surface. Almost all of mine that I keep in 32oz cups usually molt from the lid. 

How often do you feed them? 

It has been maybe two weeks since he last molted? He was definitely able to climb up to the top, they both spend most of their time up there and I saw him up there recently. I usually feed them every 3 or 4 days, but if I notice that their abdomen is slightly larger than normal I hold off on feeding them. 

 

[Pearson Realize]

I also attached the images wrong, you'll have to expand my previous comment in order to see the pictures

 

[Synapze]

Other than cutting back on the misting and keeping a watch on humidity, I can't think of anything else. This species doesn't require high humidity. 

 

[Synapze]

I also attached the images wrong, you'll have to expand my previous comment in order to see the pictures

I saw them, but I couldn't see well enough in the photos you posted. 

Someone smarter than I am will probably chime in to help you.  

 

[Pearson Realize]

I saw them, but I couldn't see well enough in the photos you posted. 

Someone smarter than I am will probably chime in to help you.  

Well thank you anyway! I plan on definitely cutting back on the misting for the other one, how often would you say to mist them?

 

[MantisGirl13]

Well thank you anyway! I plan on definitely cutting back on the misting for the other one, how often would you say to mist them?

Once a day if they have good ventilation. A very light mist though.

- MantisGirl1

 

[Synapze]

@Pearson Realize If you decide to keep misting them every day, I suggest misting the plastic but not the substrate, it'll keep excess humidity from building up (especially in a 32oz with fabric vented lid) but still give them a chance to drink from the droplets. Also, factor in the average humidity of your room. If it's in the 50% range which is recommended for Chinese, the humidity will be too high if you continue to mist every day. Mantids get most of their water from prey. During months when humidity is naturally lower, like winter, you will need to boost the humidity to compensate. In my climate the humidity in my home is always in the 50-60% range, so if I misted daily with the only ventilation being the fabric lid, most of my collection would be well above their recommended humidity levels, with exception of my higher humidity species. Something to think about. I'd still get a cheap humidity meter just to monitor the levels.