# Humidity and moulting - fact or fiction?



## myopicvisions

I have been toying with the idea of putting my experiences on paper, in the form of care guides for different species, and I wanted to see what others thought of this issue.

I have personally taken care of many different types of inverts over the years - both terestrial and marine - and I have found that, with the exception of really small animals, humidity is not important for molting.

Molting has appeared to me to be more of a product of nutrition and an adequate enclosure. I mean, with the exception of the threat of dessication of small specimens, and species that do-not get enough fluid from their diet, humidity has never been a problem for me - and I've raised nymphs from an egg case.

I was wondering if anyone else had noticed this. All the books that I have found make humidity out to be critical for moulting, when the process is the same for all arthropods, and doesn't vary if they are in or out of water. It appears as if all the books approach it from a naturalistic standpoint, and not ease of care.

In a perfect world, we would match the environment of our enclosure to that of the natural surroundings. But, as much as we'd like to think otherwise, we often fail on many accounts. If we get the humidity right, then we don't have enough ventilation. Wouldn't it just be easier to take a more practical approach?

What do you think?


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## BrianS

I have never kept the more exotic species like Leah so I can't say anything there but I have kept many Carolina/Chinese Mantids over the years and it seems like having good ventilation for these is very important. On these a rule of thumb I go by is if water droplets won't evaporate in a few hours there needs to be more ventilation. The tropical species probably are more humidity sensitive.

Any comments on this?


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## myopicvisions

Well, I've only cared for about three different species - one tropical, Chinese, and European. Of those, I raised nymphs from both the Chinese and the European. By the way... all but two, possibly three species are considered exotic in North America.

However, I have over a decade of experience caring for a variety of inverts. Seven years of my experience was gained as a volunteer at the national zoo in Washington, D.C. as a keepers aide. There, I took care of too-many inverts to count.

Please respond to my survey if you dissagree with me - I'd love to get a broader view. Thanks!


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## Orin

Humidity is a difficult to explain factor since things can dry out rapidly despite 100% humidity when there is high airflow and temp. If the humidity in your mantis cages were 0% they'd all be dead very quickly (place an adequate amount of desiccant in one of your cages and your mantis will die). Just because the effect is difficult to guage due to associated variables doesn't make it insignificant.


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## myopicvisions

What I'm trying to get at is this: I want to know how many people find that it's important, and why. Thus the survey.

Of all of the inverts I have kept and cultured, I have never had troubles with moults in low-humidity - provided that the animal was in good nutritional condition, and adequate space was provided. That goes for 3 mantis species, scores of spiders, damselflies, and even dragonflies!

(don't ever take an overwintering green darner nymph home - waking up to it crashing ito the blinds will freak you out!)


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## Orin

How do you know what humidity you have had molts at? What do you consider "low" himidity? 10%? 50% 70%? How are you measuring it? What temperature? (measurement is dependant)

Are you positive you know what you mean by humidity? In your question you would want to explain specifics. I'm betting noone here has a humidity meter they place in the cages. If your question is too vague the answers are unlikely to have use.


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## myopicvisions

Yes, I do measure humidity in my house - it's approximately 40-50%.

What I have been trying to get at - and only one person has noticed the intent of my post in the first place - was to determine who found it to be an important factor, and who didn't. That's why there is a poll attached, so that everyone would answer it.

Frankly, everyone who has suggested high relative humidty so-far hasn't justified their oppinions. I have been making a survey of scientific litterature - not hobyist info - and I have found a great dissparity between the two. Also, most of the species hobbyists advocate a high humidity for, do not live in a rainforest.

Also, the hardening, or sclerotization of the exocuticle is dependent on hormones, and not environmental conditions. If it was, many crustaceans - who use a very simmilar process - would never develop a stiffened exocuticle.

You can find a complete description of how the process works at...

http://www.agsci.ubc.ca/courses/agro/327/A....lecture.05.pdf.

I am compiling a short list of useful links on the subject, and I will post it at a later date.


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## Orin

You consider 40-50% low humidity?? My house is 25% presently.

You don't have to be a smart... Where you are confused is the effect of ambient humidity on the internal fluids of the animal. Body fluids are very much necessary for molting.


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## DeShawn

In my experience, humidity isn't always required to live, but at lower humidities, many mantids dry out too quickly during their molts and die as a result of getting caught in their skin. I have never kept any mantid below 40% humidity or above 70%.

DeShawn notices too many mantids dying in molts

DeShawn raises humidity

DeShawn notices no more mantids dying in molts...

It's as simple as that for me. No need to turn it into rocket science. I raise most of my mantids under the same conditions (70-80°F and 40-70% humidity). The room they are kept in is always around 40-55% humidity depending on time of year. For the more "exotic" species, I just mist their containers once or twice a day.

I have noticed that some species seem more healthy and active when kept at higher humidities, namely ghost mantids. That alone was enough reason for me to keep them at a higher humidity.


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## myopicvisions

I didn't intend to evoke any hostility from anyone, I was just hoping that people would respond to the poll, and generate thoughtful disscussion on the matter.

I appologize - I enjoy debating. That is often misunderstood, and taken as hostility. But, I assure you that I didn't intend to offend. I just wanted to know why people felt the way that they did. That said, the following is my oppinion - but I still look forward to hearing reasoned oppinions from others.

Stress uses valuable energy that an individual may need in order to survive the whole process. In my oppinion, founded on experience carring for a wide variety of exotic arthropods - but only 3 species of mantids - overall health, nutrition, and keeping stress to a minimum, are important factors to the whole process. I am open to the possibility that environmental factors such as low humidity may stress-out an animal, thus endangering it durring molting. But I must respectfully point out that it isn't a "drying out" process. If it were, all crabs would be soft shell crabs.

Thank you!


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## Rick

I don't think anyone is getting hostile. But many people do think they know everything and are not open to new ideas or thoughts. We have some real knowledgable people here so they are going off what works for them in regards to mantids. I am with DeShawn on this one. What I am doing now is not what most people say to do in regards to humidity but my mantids are molting fine.


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## myopicvisions

Yeah... what works for you, is what works for you. I really did just want to get a disscussion going. I am all for the free exchange of ideas, and I think I have learned a few things from some of the responses, but a few of the responses weren't so friendly.

But I am glad that a few people responded with the reasons for their oppinions, but I found a few to be discouraging, admonishing me for studying the subject, even saying, "No need to turn it into rocket science" or, "You don't have to be a smart".

Anyway, I'll keep an eye on the postings here, but I feel discouraged from starting any new threads.  

Happy holidays everyone


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## Jesse

Your poll does not include "I don't know" I have been keeping mantids for several years and I have had mixed results when it comes to keeping an eye on humidity. For example I am currently breeding S. centralis, I figured since they are in the same genus as lineola, I could keep them the same.(I've had success with lineola at ambient humidity (40-50%) and room temp), well when it came to molting into adults, most of them had deformed wings. So I increased the humidity by putting a dish of water in each of the subadults enclosures, and they were still molting out deformed(66% of them). The temps were 75-77 degrees, but maybe for S. centralis they need to be higher? Sorry if I got a little off topic.


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## myopicvisions

Do they have enough room, and are there a variety of perches available? I had trouble with deformities when I didn't have adequate perches.

Also, surface area is the trick to increasing humidity - simply putting a dish of water wont help that much. Try moistening a clump of moss, or putting something absorbent in there soaked in water. Or, try what I do - an inch of gravel covered by soil/bark, and keep the gravel water-logged. That also helps if you plant your terrarium.


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## Jesse

> Do they have enough room, and are there a variety of perches available? I had trouble with deformities when I didn't have adequate perches.Also, surface area is the trick to increasing humidity - simply putting a dish of water wont help that much. Try moistening a clump of moss, or putting something absorbent in there soaked in water. Or, try what I do - an inch of gravel covered by soil/bark, and keep the gravel water-logged. That also helps if you plant your terrarium.


Trust me, the surface area was not the problem, in some of the enclosures I had a shallow layer of water on the bottom. I rear too many mantids at a time to get fancy with substrate. Also I have given them plenty of room, and the entire top of the enclosures are mesh. I stay away from putting too many perches in an enclosure because I have had many a mantis decide to molt low on a perch too close to the bottom, and get all bent and deformed or not make it out of the molt (because they run out of room). My best guess is that it may be temperature related. My ghost mantids have been molting to adults around this same time and they are kept at 40-50% humidity, and I have had no problems with them? I appreciate the advice.


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## Orin

I also feel discouraged, however, from responding to newbie questions. It is sad to be insulted for trying to help.

(Going off topic as well as referencing unnamed sources which do not exist in the arena insinuated all to support a false pretense.) You are welcome to the last word as you have tought me not to answer myopicvisions (the irony of that name...).


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## Rick

Here is what I do. I place about a 1/4 of wet sphagnum moss in the bottom of each enclosure. Every other day I mist the moss and the sides of the enclosure. The humidity in the house is around 50%. I have had few problems as far as molting goes.


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## Ramona

Not to sound stupid here, but I am concerned about humidity as well. I have lost a few more nymphs this winter than last and I am in a different classroom that is drier than last year (15% humidity in the room itself). Part of the loss is perhaps because I have many more nymphs this year than last. ( 35-40 compared to 12) I have two questions-- if you use sphangum moss in the enclosure, how often do you replace it?

2nd question--once the nymphs have molted two or three times, don't they usually have a better chance of reaching maturity that those who have not yet molted at all?


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## Rick

Ramona, the moss usually seems to last a couple weeks. The smaller the mantis the longer it lasts. The moss does not go bad but dropped food tends to mold when it hits the moss. So the bigger the pieces of dropped food the worse it gets. However it does take awhile to grow mold. The stuff comes dry and I get it soaked and then put a half an inch in the bottom. I mist the inside of the glass every day and every other day I rewet the moss. Works really well as I have had no mismolts or deaths. And yes it does seem the older the nymphs get the better they seem to survive. I lose so many before the first molt. But once they get established they seem to be ok. Some can and will still die however. I have three left from the ooth that hatched in Sept and those are already subadults. Did both of the ooths I sent you hatch?


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## Orin

Hi Ramona,

I'm having trouble locating your e-mail and private messages don't work here unfortunately. Is Monday OK?

Thanks,

Orin


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## Birdfly

> Do they have enough room, and are there a variety of perches available? I had trouble with deformities when I didn't have adequate perches.Also, surface area is the trick to increasing humidity - simply putting a dish of water wont help that much. Try moistening a clump of moss, or putting something absorbent in there soaked in water. Or, try what I do - an inch of gravel covered by soil/bark, and keep the gravel water-logged. That also helps if you plant your terrarium.


Im sorry but i thought you didnt use any humidity in your insect terrariums ?


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## Birdfly

> I didn't intend to evoke any hostility from anyone, I was just hoping that people would respond to the poll, and generate thoughtful disscussion on the matter.I appologize - I enjoy debating. That is often misunderstood, and taken as hostility. But, I assure you that I didn't intend to offend. I just wanted to know why people felt the way that they did. That said, the following is my oppinion - but I still look forward to hearing reasoned oppinions from others.
> 
> Stress uses valuable energy that an individual may need in order to survive the whole process. In my oppinion, founded on experience carring for a wide variety of exotic arthropods - but only 3 species of mantids - overall health, nutrition, and keeping stress to a minimum, are important factors to the whole process. I am open to the possibility that environmental factors such as low humidity may stress-out an animal, thus endangering it durring molting. But I must respectfully point out that it isn't a "drying out" process. If it were, all crabs would be soft shell crabs.
> 
> Thank you!


But those crabs would be inside out and dead as a dodo if they were to shed in low, or no humidity, wouldn't they[fit,healthy or non stressed]. Also most mygalomorph spiders would dessicate and blow away in low humidity as their book lungs need humidity to breath properly. . life evolved first from the water, lower life will always require it live properly.


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