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Mealworms bedding

I'm just starting out... I have rye, can that be use for bedding ? Thank you


  • Yes & you can also mix rye with other grains.

  • In fact, recent research states that mixing grains is more beneficial that not.. Feeding of ordinary mealworm largely consists of residual products in the form of bran from various cereals. Over the past few years research has examined the importance of the feed composition for the larvae’s growth - and the results are that a varied feed with several different components (including pea, wheat, oats and rye flour) gives a higher yield because the larvae grow faster and get bigger before pupating.

    Mass of Worm Related to Number of Components in Substrate

    Chicken feed has been among the most effective but also most expensive compound foodstuffs for larval breeding. These mixtures are also used in breeding other insects. However, feed mixes are now being developed specifically for mealworm, and will in all likelihood yield a higher yield at the same or lower price after further adjustments. The same feed is often used for larvae and adult beetles, but at present there is a focus on developing lifestyle-specific compound feed. The larvae have a high feed conversion rate (2:1), while adult beetles eat only a fraction of the feed that the larvae consume. At the same time both larvae and adults need a wet feed like water source to optimize both the yield of larva biomass and the number of eggs.

  • edited March 2018

    Thanks a lot for information about how to care of these worms. You are really great consultant on this issue

  • Hi Moofisilla, - An ideally blended mealworm larvae diet would be interesting to know that is more cost effective than wheat bran. Meanwhile, here are some thoughts on your linked ideas. Because larvae go through different stages (instars) I will be refering to late stage (larger, rather than young) larvae; but not those that are pre-pupation [{ ie: some generalization may ( ? ) be described that does not always carry over into all larval stages }].

    Just to get this out of the way I will say that the moisture content of brewery waste may not be as significant in boosting mealworm larval weight as presumed. The product has residual yeast with their flavenoids, flavenols, anti-oxidants & amino acids; early laboratory insect artificial diets often included yeast extract [{ I think ( ? ) I have posted elsewhere in Forum how to make yeast extract }].

    Another observation about mewlworm larvae & water concerns their temperature. What follows may also explain why at different ages the colony density of larvae seems relevant; namely how temperature measured next to colony may be less than temperature being generated inside the mass of larvae [{ to which I would add the friction contact when moving to feed among others }].

    The fat content in the larval feed being metabolized generates 1.17 grams of metabolic water from ever 1 gr. fat. While the carbohydrate content in larval feed being metabolized generates 0.56 grams of metabolic water from every 1 gr. of carbohydrate. As for protein content in karval feed being metabolized generates 0.5 grams of metabolic water from every 1 gr. of crude protein.

    If the larval core temperature is 37°C their metabolic rate goes up (enzymes working at greater rate) & they are generating lots of metabolic water. In fact, so much internal water they need to disperse some water & living in conditions that are both hot & moist (humid) they do not do so well - being water-logged" so to speak, as if had dropsy. This is one reason places like Thailand do not rear mealworms & instead herd crickets.

    Even at 30°C larval core tempetature mealworm larvae can not slow their metabolism very well in order to hold steady their tissue ratio of internal water to live dry matter; which entails being able to somehow regulating metabolic water from food assimilation.

    88% relative humidity is a reference point for where larvae have limits on getting rid of water. When larvae are not fed & relying on metabolizing their reserves there is a dual paradigm.

    Un-fed larvae in greater than 88% relative humidity will gain weight in water, while un-fed larvae in lower than 88% relative humidity will lose weight in water. There is a temperature gradient too, since from 23°C - 30°C larvae not eating can gain weight even without eating at 90°C relative humidity [{ reportedly up to 18% more weight just from water, without eating}].

    A (nice) core mealworm larval temperature of 23°C gives their enzymes adaptability to adapt internal metabolic water proportion to live dry matter when the air is very overly humid; they can slow metabolism to limit metabolic water. Yet at the same 23°C if the air is dry the larvae can ramp up their metabolism (enzymatic rate) to increase internal metabolic water.

    The un-fed mealworm larvae does not lose total weight, because burning fat reserves generates more grams of water than gr. fat used up & burning carbohydrate reserves generates less gr. water than gr. carbohydrate used. That metabolic water production balances out so that un-fed larvae do not lose weight in that context - they only lose weight when their bodies evaporate water due to low relative humudity.

    My point being that when we read about "wet" food for larval growth it is not a linear trend to more is better. The question arises about experimental weights being greater for larvae given "wet" feed takes into account whether the larval live weight is reflecting a skewed dry weight to water weight ratio.

    Fed on bran & turnips a 88 gr. larvae can average 30.5% dry weight, a 118 gr. larvae can average 42.4% dry weight, a 125 gr. larvae can average 41.2% dry weight & when 175 gr. larvae can average 42.2% dry weight. Most people find age mate mealworm larvae are not constantly uniform in weight & I propose this is, in part, from how individuals' core temperature during feeding [{ & general relative humidity inside }] in the herd can vary.

    Continues ....

  • Continuation ....

    One (1) gr. protein consumed by mealworm larvae also devolves about 0.5 gr. metabolic water, plus about 0.5 gr. uric acid. A live fed larvae has between 0.25 - 0.5% uric acid inside it.

    If it excretes 0.5 gr. uric acid that means it's live dry weight [{specifically}] is reduced by 1 gr. (dry weight). Considering mealworm larvae feces (frass) can be up to 50% uric acid any larval diet overloaded with protein has to look at whether it is fostering a desired ratio of live dry matter to water weight.

    At this point I want to get into some exclusively wheat bran larval [{ late instar only as above }] diet aspects; maybe it will provide insight for those considering diet formulas. Crude protein in decent quality wheat bran is about 156.6 mg per 1,000 mg (1 gr.), of which 59% is used by large larvae.

    Bran protein breaks down to gliadin (21.6 mg/1,000 mg dry bran; of which 82% hydrolized by larvae), K2SO4 soluble protein (70 mg/1000mg of dry bran; of which 88% hydrolized by larvae), & other protein (49.2 mg/1,000mg of dry bran; of which 55% hydrolized by larvae). If we generalize that an average of 75% crude protein in bran is hydrolized still less than 60% of that is utilized once we take into account adjusting for the uric acid being excreted [{1.99 gram protein devolves 1 gram uric acid }]. And to be precise, although not here dealt with, there is some nitrogen in bran that does not actually come from bran protein that is also in the frass excreted.

    Large mealworm larvae use about 59% of the ingested crude protein, 60% of carbohydrates & 73% of crude fat contained in the bran ingested. Although bran has about 6.45 parts carbohydrate to 1 part fatty acid ratio the larvae will convert so much ingested carbohydrates into fat that larval tissue is only 0.67 parts carbohydrate to 1 part fatty acid ratio. This way they can conveniently "burn" (oxidize) a little fat to maintain internal metabolic water ratio to live dry mass (see preceeding comment) when conditions are dry (ex. in stored grain) without losing development trajectory of gaining weight.

    Wheat bran, besides it's crude protein content % utilized (3rd paragraph above), also contains the following - with the specific different % used by larvae broken down. Numerical values are for mg per 1,000mg (1 gr) & then the % of that nutrient used by large larvae when consumed is enumerated.

    Wheat bran, depending on quality, contains 266.9 mg/1,000 mg hemi-cellulose, with 36% being used; 195.3 mg/1,000 mg starch, with 59% being used; di-saccharide 94.2mg/1,000 mg, with 96% being used; 2.4 mg/1,000mg fructose, with 46% being used; 1.2 mg/1,000mg glucose, with 67% being used; 54.6 mg/1,000mg fatty acids, with 83% being used, 64 mg/1,000 mg ash, with 17% being used; 18.9mg/1,000mg non-saponifieds, with 46% being used; & 156.6mg/1,000 mg crude protein with 59% of that ingested being used by large larvae. For a reference, in context to what was elaborated in the preceeding comment, figure that 1,000mg (1 gram) wheat bran (with this stated composition) consumed by a large late instar mealworm larvae devolves 60 mg of metabolic water inside it.

    Regarding this & the immediately preceeding post see K.Mellanby (1932) "The effect of Atmospheric Humidity on the metabolism of the fasting mealworm ...."; & also Evans w/Goodliffe's (1939) "The Utilization of food by the larvae of the mealworm ...." Any errors interpreting their data are mine; being pressed for time potential comment errors have not been checked for & texts as written not edited.

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