Doyle's Dart Den


(Tribolium confusum)
by David Doyle

Tribolium confusum (i.e..,  flour beetle, confused flour beetle, or rice flour beetle) grows to a size of 3-4mm (1/8 inch) and will live up to 2 years.  The female will lay between 300 - 400 eggs with the greatest production within the first week of adulthood.  The eggs hatch in 3 - 5 days and the larva emerge.  The larva are approximately 6mm (1/4 inch) long and appear to be very similar to mealworms, but much smaller.  The larva are the preferred food for the small frogs such as dendrobates and mantellas, fish, and small lizards.  The adults are often spit out by the frogs; this may because of a gas emitted by the adults which contains a compound called quinones.  Also, the adults have a hard exoskeleton which results in a high chitin content.  On average, the larva will develop into adults in 26 days.  It should be noted that care should be taken to prevent the colony from becoming over-populated with adults as they will become cannibalistic. Also, overpopulation can encourage the transmission of the protozoan parasite, Adelina tribolii.

Plastic shoe box
Kitchen strainer
Media mixture

2 parts (i.e., 2 cups) whole wheat flour (strain flour to remove the bran)
2 parts (i.e., 2 cups) regular flour
1 part (i.e., 1 cups) yeast (I use regular baking yeast and some people use brewer's yeast)
        Using the "cups" as the "parts" the cost is approx. $0.70 per culture

First make up some media.  Strain 2 parts (i.e., 2 cups) of whole wheat flour into one of the shoe boxes.  To this, add 2 parts (i.e., 2 cups) of regular flour and 1 part (i.e.,1 cup) of yeast.  Stir the mixture until it is homogenous. At the end you want about 2 inches of media in the 2 shoe boxes.  Add  a good number of beetles (say about 100) to one of the shoe boxes and let it set for about 2 to 3 weeks.  As noted above "The female will lay between 300 - 400 eggs with the greatest production within the first week of adulthood" so it is best to start the culture with young adults or use larva that are tuning into adults.  Don't worry about this at first.    Keep the cultures at normal room temperature and humidity.  Do not add any moisture sources as it will often cause mold.  After the 2 to 3 weeks strain the 1st culture and add the beetles and any larva you get to the 2nd culture.  This will leave only eggs and small larva in the culture and you will have about a month or two to feed out of this culture before the number of adults become large.  In about a week or two you will be able to strain the 1st culture and get mostly larva.  You should be able to feed out of this culture for about a month before the percentage of beetles starts to get high.  At this point, you will have strained the 2nd culture about 2 weeks ago and will be able to feed out of it.  The 3rd shoe box is for when you need to strain the entire culture.
So here would be the schedule for setting everything up:
Day 1 Make up the media and introduce beetles into culture #1
Day 1-20 Let them set (This is when the adults lay eggs)
Day 21 Strain the beetles and larva from culture #1 and put them in culture #2  (This removes the      adults and  leaves eggs and small larva.)
Day 22-34 Let them set  (This is when the eggs hatch and develop into larva)
Day 35 Start feeding out of culture #1
Day 42 Strain culture #2 and put larva into another container with some media to keep the adults to setup new cultures.
Day 63  The number of larva will be reduced in culture #1 so start feeding out of culture #2 and place the adults back into culture #1 and start over.

You can normally get two cycles out of each container of media.  Like most insects, the flour beetle life cycle is influenced by temperature and moisture so you may find that you will need to adjust the above times.

  For places to order supplies and starter cultures click here.

To feed, dip the strainer into the culture you are feeding out of and tap it until the flour is gone and you only have larva and maybe some adults.  Like flies, place the larva and adults into a ziplock bag with calcium powder and cover them with the powder.  You may find that the larva do not pick up as much powder as flies do.  Then, place the larva into the tank.  You can sprinkle them along the floor or place them into some kind of container (I use a soda cap or plastic jar top).

An alternate method is to establish the culture and strain some of the media to remove the larva and adults.  Then the larva and adults are placed into a shallow container such as a film canister that has been cut down to about 1/3 of the original height.  Place the container right side up back into the culture and allow the adults to crawl out of the container and back into the media.  After about 5 minutes, most of the adults should have crawled out of the container.  I have also seen people place the larva and adults into a container with a piece of cloth or fiberglass window screen leading from the inside to the outside back to the media.  This allows the adults a way out of the container and back to the media.  These alternative methods do not require allowing the adult to stay in the culture for that first 2 - 3 weeks to lay eggs then straining the media to remove the larva.

How many to feed??  One advantage of flour beetle larva is that they normally do not move much once introduced into the enclosure and will not normally cause stress to the animals being fed (ie., crawl all over the animals).  For froglets feed approx. 5 -7 larva per frog each day.  If they are all gone the next day increase the amount.  Also watch the froglets and make sure they are feeding.  Sometimes it takes them a while to figure out why the larva are there. 

I personally have 10 adult frogs and 7 that are about 1/2 grown that I'm feeding.  I keep 3 cultures that I feed out of and have more than enough.  It should be noted that I do not only feed flour beetles, I also feed fruit flies, spring tales, and in the summer yard sweepings.  I personally don't like to eat only one thing all of the time and I donít think my frogs do either.  Just keep in mind that you can never have too much food.  The worst problem most people (beginners and long time keepers alike) have is crashes in their food supplies.  Also, having extra food will make you VERY popular with friends when they have food problems.  Times like that are great times to do some trading.

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