Detection and removal of brood infested with eggs and larvae of small hive beetles (Aethina tumida Murray) by Russian honey bees

Abstract

SummaryThe response of Russian honey bees to brood infested with small hive beetle (SHB) eggs and larvae was compared to that of a commercial stock (predominantly of A. m. ligustica). Test brood was grouped as follows: a) NoP = no perforation either of capping or cell wall; b) PWall = perforation of cell wall only; c) PCap = perforation of capping only; and d) PBoth = capping and cell wall perforations. All perforations were made by SHB. Our results showed that brood cells with perforations of the cell wall (PWall and PBoth) had the highest infestation (76.53 ± 2.10%) and number of eggs (58.46 ± 2.85 eggs). Because PCap showed low levels of infestation (29.17 ± 3.31% and 15.60 ± 1.31 eggs per infested cell), we calculated brood removal based on data from PWall and PBoth groups. Within 6 h, both stocks removed the contents of 39.24 ± 4.94% of PWall cells. A higher removal rate of 50.51 ± 5.80% was observed in PBoth cells. These two groups of brood had the highest numbers of eggs per infested cell (50–70 eggs). Eggs hatched after the 6 h observation and subsequent hygienic removal was of brood infested with larvae. At 20 h, additional 56.41 ± 4.62% (PWall) and 42.04 ± 4.91% (PBoth) removal rates were observed. Overall, the cumulative removal rates for both stocks were similar with means of 85.11 ± 2.98% and 84.32 ± 4.29% for the commercial and Russian honey bees, respectively. In conclusion, we observed that both honey bee stocks were able to detect eggs inside the sealed brood cells and remove them with the infested brood.