Svilen Lazarov and Ivanka ZhelyazkovaTrakia University, Faculty of Agriculture, Department of Animal husbandry – Non-ruminants and other animals, 6000 Stara Zagora, Bulgaria
Lazarov, S. & Zhelyazkova, I. (2020) Hygienic behaviour and dimensions of the chitin body parts in worker bees (Apis mellifera L.) Bulg. J. Agric. Sci., 26 (Suppl. 1), 141-149
In the present study a total of 28 bee colonies from the local honey bee (Apis mellifera L.) have been tested for level of expression of hygienic behaviour. On the basis of the test, two groups of bee colonies have been identified - hygienic (these clean over 95% of the cells with dead brood up to the 48th hour after piercing) and non-hygienic (these clean less than 95% of the cells with dead brood up to the 48th hour). Morphometric measurements of the chitin body parts of the worker bees have been carried out on 12 features. Three of the studied morphological features (forelegs, upper mandibles, and proboscis) relate to the cleaning and polishing of the beecomb cells and maintaining hygiene in the bee nest. The upper mandible and the foreleg parts are new features not included in the measuring methods used in beekeeping. High degree of reliability (p≤0.001) between hygienic and non-hygienic bee colonies has been determined for 7 morphological features - length of the fore wing and the first part of the cubital cell, length of femur and width of first tarsus of the foreleg, length of proboscis and length and width of the upper mandible. For the feature number of hooks on the hind wing a low degree of reliability (p≤0.05) has been established. The results obtained in the present study concerning differences between morphometric signs of bee workers from hygienic and non-hygienic bee colonies complement the information available so far on the factors influencing the expression of hygienic behaviour in bees.