Heritability of grooming behaviour in grey honey bees (Apis mellifera Carnica)

Abstract

Grooming behavior is considered an important defensive mechanism of honey bees against Varroa mites. The aim of this study was to reveal whether grooming behavior is a useful criterion in breeding of Varroa-tolerant bees. To obtain a reliable evaluation the environmental influences were excluded. The degree of grooming potential was estimated by the percentage of damaged mites in the total number of fallen mites. The heritability of grooming behavior throughout the three consecutive generations of queens was assessed by mother-daughter regression method. Among unselected queens, expressed grooming behavior was recorded only in colonies with F1 queens (36.27%), but not in colonies with P queens and F2 queens (33.69%, 31.66%, respectively). Significant differences in grooming behavior were found between colonies of P and F1 queens (p lt 0.001), and between colonies of P and F2 queens (p lt 0.05). However, all of the three generations of selected queens showed expressed grooming behavior (37.99%, 39.42% and 38.58% in Ps, F1s and F2s, respectively) without significant (p>0.05) difference among them. Nevertheless, the relatively low heritability of grooming behavior in the three generations of queens examined (h2yx=0.49±0.02; h2zx=0.18±0.01; h2zy=0.16±0.01) indicate that breeding colonies for grooming behavior only cannot be advised to beekeepers whose aim is to breed bees highly tolerant to Varroa mites.

Negovateljsko ponašanje se smatra značajnim mehanizmom odbrane pčela od Varroa krpelja. Cilj ovog rada je bilo ispitivanje negovateljskog ponašanja, procena njegove heritabilnosti i mogućnosti povećanja ekspresije te osobine putem selekcije. Radi dobijanja pouzdanih rezultata korišćenja je metodologija kojom se uticaj spoljašnjih faktora isključuje. Ispoljenost negovateljskog ponašanja procenjivana je na osnovu procenta oštećenih u ukupnom broju otpalih krpelja. Heritabilnost negovateljskog ponašanja praćena na kroz generacije matica i procenjivana metodom regresije majka-ćerka. Među neselekcionisanim maticama, negovateljsko ponašanje bilo je izraženo samo kod matica F1 generacije (36,27%), ali ne i kod P (33,69%) i F2 generacije (31,66%). Statistički značajne razlike u negovateljskom ponašanju zabeležene su između društava P i F1 matica (p lt 0,001) i između društava P i F2 matica (p lt 0,05). Međutim, selekcionisane matice sve tri generacije (Ps, F1s, F2s) su imale izraženo negovateljsko ponašanje (37,99%, 39,42% i 38,58%) bez statistički značajnih (p>0,05) razlika među njima. Ipak, nizak koeficijent heritabilnosti praćene osobine (h2yx=0,49±0,02; h2zx=0,18±0,01; h2zy=0,16±0,01) ukazuje da se pčelarima ne može preporučiti selekcija pčela samo na negovateljsko ponašanje ako je njihov cilj uzgoj pčelinjih zajednica povećane otpornosti na Varroa krpelje.