Trevor and others interested to know single reps vs 4 reps. In addition to Jerry's comments, regarding statistics designs, variability and experimental errors. I would like to add: There was a significant correlation at the end between the two methods. However, we found that there were lots of variability when we used one single replication and compare results to another replicate done few days ion the same hives. There were several factors identifies as sources of variability; not enough Liquid N2 applied, Lost counts when you count over 100, bee behaviour, and pupal age. It also takes longer time to count " oops let me start again,,,," and it requires to take counts after 48 h sometimes 72 h. To increase precision, Spivak recommended that this test has to be repeated 2 times to get better results. In our program, we needed to improve the system to do the job in one day and have more accurate results without the need to go back to the field to run another test. We found that 4 small replicates of area of circle 1.5" diameter (think of stainless steel butter cup with bottom removed) provided the following: 1. you can easily find areas with pupae of the same age to be used with a small circle 2. It takes the bees 24 h to do the job. 3. easy to count 4. Better statistical design with less experimental errors 5. You don't have to repeat in few days as recommended by Spivak 6. saved time to travel back in 48 h to those fields. Thus we were able to do many operations in one location in a day. Next day go back and count and move on to another location. I like also to mention that I found that beekeepers are using different kind of circle size 3 - 7 " diameter. Still they expect the bees to do the job in 24 or 48 h. I always recommend that a beekeeper needs to first find the average time for his bees to remove 50% of the cells, specially when you use large diameters. You need to establish this first as a reference point. Then, you determine, when you should go 24, 48, 72 h to count removed cells. Medhat Medhat Nasr, Ph. D. Provincial Apiculturist Crop Diversification Centre North 17507 Fort Road Edmonton, AB, Canada T5Y 6H3 Tel: (780) 415-2314 Fax: (780) 422-6096 Mailto:[log in to unmask] *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html