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This seems like a good point in the thread to discuss humidity. It's not that they prefer 55% humidity, but that most studies use 55% to reduce problems unrelated to what the scientist is studying. The mealworms will perform somewhat better at higher humidities, but as humidity increases above 55% (especially as it exceeds 70%) the likelihood of infection by mites and entomopathogenic fungi also increases. Under very high humidity levels it is only a matter of time before catastrophic infections wipe out much of a colony. Indeed, mites are everywhere in the environment as are fungal spores. Under lower humidity levels these pests usually never become a problem, but higher humidity is one of the most important environmental factors that trigger reproduction or sporulation. The scientist studying T. molitor isn't really that concerned about maximizing reproductive rates and their mealworms will develop and reproduce just fine at 55%. Consider the dreaded grain mite-- it is unable to survive at humidities lower than 55% but reproduces at explosive rates as humidity approaches 90% (http://ento.psu.edu/extension/factsheets/flour-and-grain-mites). As hobbyists we have to trade off an increased reproductive rate with almost certain calamity as we increase the humidity. We can do things to limit grain mite exposure to our colonies (e.g. freezing, baking, microwaving), but we can't easily eliminate them entirely from the environment.
I live in one of the driest places on the planet, our humidity is low and measured in single digits for much of the year. I don't add any moisture to the colony beyond that contained in the vegetables I feed them. It's more important to me to have a constant production rather than a slightly higher rate of production punctuated with periodic disasters. I've raised them long enough to have experienced all the disasters that can befall a colony. The vegetables alone will increase the humidity at the level of the substrate. If your ambient humidity is 70%, adding vegetables will further increase the RH at level of the substrate. This effect can be exacerbated as air flow in and out of the colony is limited (e.g. with a lid or drawer system). For this reason it may be safer to keep ambient humidity down but occasionally add moistened cotton balls from which the mealworms will obtain moisture. If you're still worried about them getting enough moisture, consider the special talent our mealworms possess. They have a strange ability to pull water molecules out of thin air directly through their rectum.
Strange, but true.
Thanks for the additional insights. The link was informative. I would like to see a research link on mealworms, too.
This seems like a good point in the thread to discuss humidity. It's not that they prefer 55% humidity, but that most studies use 55% to reduce problems unrelated to what the scientist is studying. The mealworms will perform somewhat better at higher humidities, but as humidity increases above 55% (especially as it exceeds 70%) the likelihood of infection by mites and entomopathogenic fungi also increases. Under very high humidity levels it is only a matter of time before catastrophic infections wipe out much of a colony. Indeed, mites are everywhere in the environment as are fungal spores. Under lower humidity levels these pests usually never become a problem, but higher humidity is one of the most important environmental factors that trigger reproduction or sporulation. The scientist studying T. molitor isn't really that concerned about maximizing reproductive rates and their mealworms will develop and reproduce just fine at 55%. Consider the dreaded grain mite-- it is unable to survive at humidities lower than 55% but reproduces at explosive rates as humidity approaches 90% (http://ento.psu.edu/extension/factsheets/flour-and-grain-mites). As hobbyists we have to trade off an increased reproductive rate with almost certain calamity as we increase the humidity. We can do things to limit grain mite exposure to our colonies (e.g. freezing, baking, microwaving), but we can't easily eliminate them entirely from the environment.
I live in one of the driest places on the planet, our humidity is low and measured in single digits for much of the year. I don't add any moisture to the colony beyond that contained in the vegetables I feed them. It's more important to me to have a constant production rather than a slightly higher rate of production punctuated with periodic disasters. I've raised them long enough to have experienced all the disasters that can befall a colony. The vegetables alone will increase the humidity at the level of the substrate. If your ambient humidity is 70%, adding vegetables will further increase the RH at level of the substrate. This effect can be exacerbated as air flow in and out of the colony is limited (e.g. with a lid or drawer system). For this reason it may be safer to keep ambient humidity down but occasionally add moistened cotton balls from which the mealworms will obtain moisture. If you're still worried about them getting enough moisture, consider the special talent our mealworms possess. They have a strange ability to pull water molecules out of thin air directly through their rectum.
Strange, but true.
Thanks for the additional insights. The link was informative. I would like to see a research link on mealworms, too.
