## 2 Materials and Methods  
### Worker Rearing  
The experiment was conducted in the apiary of the University of Life Sciences in Lublin (Poland; 51.224039 N-22.634649 E). Six drawn honeycombs in which no brood was reared were selected. Two of the combs were drawn out on a small-cell foundation (smComb) (cell width 4.90 mm) and four were drawn on a standard-cell foundation (STComb) (cell width 5.50 mm).  
The length of the horizontal segments (one in each quarter of the comb) was measured on each side of each comb. In the central part of the comb, the widths of 10 adjacent cells in contact with the vertical side walls were measured. Each of the 10 cells was measured separately [11]. The measurements were made on photographs with the use of the Multi Scan digital image analysis system v. 14.02 (segment measurement option) supplied by Computer Scanning System II, Warsaw [15].  
In spring, more specifically in the last ten days of April, four honeybee colonies with similar strength and structure were selected. Two colonies were kept on small-cell combs (smColony) and the other two were kept on standard-cell combs (STColony). The colonies were kept in Ostrowska-type vertical hives and were headed by naturally mated Buckfast sister-queens. Buckfast bee colonies were selected for the study, as they had adapted successfully to living on small-cell combs in the apiary of the University of Life Sciences in Lublin [15]. In each colony, the workers populated one brood chamber and one honey super, each with 10 frames (360 \(\times\) 230 mm). Two brood combs from the center of the brood chamber of each smColony (colony kept on small-cell combs) were transferred to the honey super. A queen-excluder frame cage divided into two parts containing one comb each was placed in this space. The smComb (small-cell comb) was placed in one part and the STComb (standard-cell comb) was placed in the other. Next, the queen was kept on each comb for 24 h. After this time, the frame cage was removed from each colony, and the removed brood combs were placed in the center of the brood chamber.  
One brood comb was transferred from the center of the brood chamber to the honey super from the nest of each STColony (colony kept on standard-cell combs). The queen-excluder frame cage containing one comb was placed in this space. A STComb on which the queen was kept for 24 h was placed in the frame cage. After this time, the frame cage was removed from each colony and the removed brood comb was placed in the center of the brood chamber. After 19 days, each brood comb was placed in a separate mesh frame cage and transferred into an incubator (34.5 \({}^{\circ}\)C and 60% RH), where it was kept until the emergence of workers. Approximately 100 workers from each comb were transferred into a separate cage and left in the incubator (26 \({}^{\circ}\)C and 60% RH) for 7 days to allow their chitin cuticle to harden. Bees in the cage were fed sugar syrup with sugar to water in a 1:1 ratio. Three groups of workers corresponding to the combinations of the comb type and the foster colony type were obtained: bees reared in small-cell combs in colonies kept on small-cell combs (smComb + smColony), bees reared in standard-cell combs in colonies kept on small-cell combs (STComb + smColony), and bees reared in standard-cell combs in colonies kept on standard-cell combs (STComb + STColony).  
The scheme for obtaining worker bees is shown in Figure 1.