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Frequently Asked Questions




When will my order arrive?

We ship the same day you order Monday - Friday before noon (except crickets and silkworms), this chart gives your arrival date:




I need my order tomorrow on Saturday, what can I do?

Give us a call at (800) 777-WORM or (310) 635-1494, if it's before noon Pacific time on Friday we can send your order overnight for Saturday delivery for a $15 to $20 special delivery fee by either FedEx or UPS.   


Do you ship to Canada?

Yes, just choose Canada as your country at checkout.  We will ship the same day we receive your order before noon Pacific time via FedEx Priority or Express.  To find ship times, calculate ship times select zip code 90220 in the 'from' section on this page: FedEx Transit Times, put in any weight and box size and choose 'office equipment' as the commodity description (we already have clearance to ship insects).


I want to break my order up into smaller bags or boxes, can you do that?

We sure can!  There is a per bag cost of $0.75 each for worms and a per box charge of $1.00 a piece for crickets.  


I'm trying to raise my own mealworms, why are they turning black?

 When pupae die and turn black, it's usually because the worms weren't given enough moisture with carrots or potatoes at the end of the larval stage. They need to store the moisture to last through pupation and will dehydrate and die if they didn't get enough.
They are also very heat sensitive.  They mustn't get any warmer than 80-85 degrees.  When they are kept at a depth more than several inches or with lots of their castings, the mealworms on the bottom will rapidly overheat (even though the room may be somewhat cool).  Sift them often to remove the castings and keep them at 2" or less.
If you are storing them in your refrigerator; you might have a spot that is too cold.  The bottom of your refrigerator is the coldest near the crisper drawers; you may have warmer and more desirable temperatures on higher shelves near the top.  A thermometer placed in your fridge is really the most accurate way to tell.


My worms smell bad, what am I doing wrong?

It's likely your substrate is too deep.  When your bedding is deeper than 2" heat and moisture will accumulate in the lower levels of the bedding and mix with the worm's droppings causing bacteria and fungus to readily grow.  Try changing your bedding material and then making your bin more shallow.  

Why don't you include bedding?

We have found that during warmer months, the mealworms will eat the bedding and increase their activity which generates more heat.  The extra heat and the castings they produce will result in a percentage of your worms dying, as well as leading to mold growing on the bran.  This isn't healthy for your worms or for your animals being fed.

If the mealworms get very hungry they will often nibble on the newspapers we pack them in (we only use newspapers with soy based inks).  We offer our custom milled bran sold with shipping included and will glady ship some with your worms in a separate container.

A great benefit of not purchasing your worms in pre-packed cups from stores with bran (besides paying retail for worms that have been shelved) is that your worms can easily be shaken into a tupperware container and refrigerated.  You won't need to pick them out of the bran individually to feed them to your animals, rather grab just your worms and pop them right in the food dish.

Why don't you include a packing slip?

We want to reduce our paper use and waste; we ship out over 1500 orders per week and that would use a LOT of paper!  Instead, we send you an electronic confirmation of your order.  

If you prefer to have a slip, please leave us a note at checkout and we will be very happy to include one.

Are your giant mealworms GMO?

While this popular misconception is very flattering, unfortunately we didn't harness the ability to geneticaly modify insects in the 1950s (which is too bad, we would be rich!).

There are lots of rumors about giant mealworms, and hopefully this FAQ will put them to rest.

There are two kinds of insects, those who go through a complete metamorphosis and pupate (beetles, flies, butterflies, waxworms) and those who don't (crickets, grasshoppers, roaches, and all true bugs).  The difference is that those who pupate have a rapid decline in growth hormone which forces them to pupate, while those that don't keep a constant level of growth hormone throughout their life time.  

We found a way to keep mealworms from having that sharp decline in hormone as it is in insects who don't pupate (crickets and roaches for example), so they won't go through metamorphosis.  The energy that they would have spent forming a pupa is now spent into growing longer and thicker.  There is no hormone, chemical, or vitamin present in a giant mealworm that isn't present in a regular growing mealworm or in insects that do not metamorphose.  

While the thought of being percieved as scientific geniuses was a lot of fun, our giants are just not genetically modified.  

What's the difference between worms for wild birds and bulk mealworms?

There is no difference at all.   We have ads placed through Google and they ask us to make separate pages to target the audience so that when you click on an ad, you land at the page designed for your interests.  But otherwise our mealworms are all the same, raised on human grade grain and vegetables with no chemicals used whatsoever in the process. 
Although most of our customers purchase for reptiles & exotic animals, backyard birding is something we really support at Rainbow and wish more people would be involved.  Herbicidal spraying has vastly reduced the return of birds in the spring because the grubs that normally emerge this time of year just aren't there anymore, and the more people that have food for wild birds the more likely we will have their beauty to enjoy.

Do you have a price list?


What are these fuzzy caterpillars in my worms?


These are the larvae of the Dermestid beetle.  They are a harmless tag-along that come with raising mealworms. They beetles can fly and come into our rooms with the mealworms to eat their grain. We are strongly against the use of chemicals with our mealworms and so we have them hand picked daily to control them. Because we are all organic, we have the occasional larvae and/or beetle come with your shipment.

We assure you they are harmless and your animals can safely eat them!

Many growers sell them calling them "clean up crew" beetles because they will also eat any dead insects that are in your bins for you.


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