Tribolium castaneum rearing, Ximena Gutierrez & Patricia Graham
Important notes
- We preferred Bob’s Red Mill 100% stone-ground whole-wheat flour that we buy in organic supermarkets. In some cases, we used the Bob’s Red Mill 100% stone-ground white whole-wheat flour to keep the beetles but have different sizes of the grain that makes difficult to collect embryos and larvae. Further note - we recently decided that the beetles also don’t grow as well on white whole wheat flour.
- We preferred Bob’s Red Mill unbleached white all-purpose organic flour and Solgar brewer’s yeast powder.
- For at least an ON we keep at -20C the flour that we are going to use, to prevent fungi contaminations of our stocks. All the flour that we used are at -20C until is going to be used, we keep at RT.
- Too dense populations will become desynchronized and can lead to fungi infestations.
- To have more details check The Beetle Book, edited by Gregor Bucher 2009.
Collect the beetles
To add the adult beetles to the flour we have different options: 1. Put a piece of paper to the beetles’ crawl, remove the adults of the piece of paper and put them in the new flour jar. 2. Sift (485 um) the flour with the beetles and collect the adults, pupae and big larvae. 3. Put the flour in a pan and collect each adult or pupae with a piece of paper. 4. Sift () the flour to collect embryos and small larvae.
Working (medium size) stock
In a clean mason jar of 800 mL with wide entrance, remove the mobile part of the lid and change it with Whatman paper circle to have the air supply; add 200 g of Bob’s Red Mill 100% stone-ground whole wheat flour and 7 g of yeast, mix well and let the flour be at RT. Add the beetles, approximately 5 mL to have happy beetles at 30C with 40% humidity and 12/12 h light/dark cycle. With these rearing conditions we have in 6-7 weeks the next generation of adult beetles.
Medium size stock
In a clean mason jar of 800 mL with wide entrance, remove the mobile part of the lid and change it with Whatman paper circle to have the air supply; add 200 g of whole wheat flour and 7 g of yeast, mix well and let the flour be at RT. Add the beetles, approximately 5 mL of beetles at 23C. With these rearing conditions we have in 3 months the next generation of adult beetles.
Fly vial
In fly vials (20 mL) we add 5 cm of whole wheat flour and yeast to have less than 50 beetles, if we have more beetles they aren’t happy. We use these types of rearing for special lines or to have crosses.
Embryo collections
In a clean mason jar of 400 mL with wide entrance, remove the mobile part of the lid and change it with Whatman paper circle to have the air supply; add 100 g of Bob’s Red Mill white wheat flour and 5 g of ground yeast, mix well and let the flour be at RT. Add the adult beetles (2 or 3 weeks old), approximately 5 mL of beetles at 25 or 30C, let them laid eggs for a couple of hours but to more than 8 hours (they decrease the quantity of the laid eggs). Sift () the white flour to collect the embryos.
Important notes
- We preferred Bob’s Red Mill 100% stone-ground whole-wheat flour that we buy in organic supermarkets. In some cases, we used the Bob’s Red Mill 100% stone-ground white whole-wheat flour to keep the beetles but have different sizes of the grain that makes difficult to collect embryos and larvae. Further note - we recently decided that the beetles also don’t grow as well on white whole wheat flour.
- We preferred Bob’s Red Mill unbleached white all-purpose organic flour and Solgar brewer’s yeast powder.
- For at least an ON we keep at -20C the flour that we are going to use, to prevent fungi contaminations of our stocks. All the flour that we used are at -20C until is going to be used, we keep at RT.
- Too dense populations will become desynchronized and can lead to fungi infestations.
- To have more details check The Beetle Book, edited by Gregor Bucher 2009.
Collect the beetles
To add the adult beetles to the flour we have different options: 1. Put a piece of paper to the beetles’ crawl, remove the adults of the piece of paper and put them in the new flour jar. 2. Sift (485 um) the flour with the beetles and collect the adults, pupae and big larvae. 3. Put the flour in a pan and collect each adult or pupae with a piece of paper. 4. Sift () the flour to collect embryos and small larvae.
Working (medium size) stock
In a clean mason jar of 800 mL with wide entrance, remove the mobile part of the lid and change it with Whatman paper circle to have the air supply; add 200 g of Bob’s Red Mill 100% stone-ground whole wheat flour and 7 g of yeast, mix well and let the flour be at RT. Add the beetles, approximately 5 mL to have happy beetles at 30C with 40% humidity and 12/12 h light/dark cycle. With these rearing conditions we have in 6-7 weeks the next generation of adult beetles.
Medium size stock
In a clean mason jar of 800 mL with wide entrance, remove the mobile part of the lid and change it with Whatman paper circle to have the air supply; add 200 g of whole wheat flour and 7 g of yeast, mix well and let the flour be at RT. Add the beetles, approximately 5 mL of beetles at 23C. With these rearing conditions we have in 3 months the next generation of adult beetles.
Fly vial
In fly vials (20 mL) we add 5 cm of whole wheat flour and yeast to have less than 50 beetles, if we have more beetles they aren’t happy. We use these types of rearing for special lines or to have crosses.
Embryo collections
In a clean mason jar of 400 mL with wide entrance, remove the mobile part of the lid and change it with Whatman paper circle to have the air supply; add 100 g of Bob’s Red Mill white wheat flour and 5 g of ground yeast, mix well and let the flour be at RT. Add the adult beetles (2 or 3 weeks old), approximately 5 mL of beetles at 25 or 30C, let them laid eggs for a couple of hours but to more than 8 hours (they decrease the quantity of the laid eggs). Sift () the white flour to collect the embryos.