Effect of Acaricide treatment on body weight and reproductive characteristics of drones of the Prioksky breed type of central Russian honeybees (Apis mellifera linnaeus, 1758)

In modern beekeeping, there is a mass death of bee colonies, one of the causes of which is varroosis. To reduce the negative impact of varroosis on the life of a bee colony, acaricides are widely used. However, the acaricidal preparations negatively affect the reproductive performance of drones. Various reports note their ambiguous effect on some the development of individuals in a bee family, including drones, and, consequently, economically useful traits (honey and wax productivity, queen egg production, resistance to diseases). In this work, for the first time, we obtained data that acaricidal preparations of amitraz, fluvalinate and thymol + oxalic acid negatively affect the reproductive performance of honeybee drones of the Central Russian breed and cause a deterioration in sperm quality. The aim of the work was to study the effect of acaricidal preparations on the fertility, deformation and concentration of spermatozoa of honey bee drones of the Prioksky breed type of the Central Russian breed, as well as on their body weight. The work was carried out at the experimental apiary of the Federal Beekeeping Research Centre (Rybnoye, Ryazan Province, spring-summer 2021). Colonies of Central Russian bees ( Apis mellifera Linnaeus, 1758) of the Prioksky breed type were assigned to four groups, three bee colonies each: group I was not subjected to treatments (control), groups II-IV were treated. The degree of Varroa destructor infestation was 1-2 % in all groups. After the appearance of one-day-old drone brood, each test group was treated with one of three acaricidal drugs to combat varroosis. An amitraz-based drug («Sichuan Wangshi Animal Health Co., Ltd.», China; hazard class 3, SanPiN 1.2.25.84-10) was used in group II, a fluvalinate-based drug («Shanxi Zhenxing Fish & Bees Medicine Industry Co., Ltd.», China; hazard class 3, SanPin 1.2.25.84-10) in group III, and a drug containing oxalic acid («Shandong Deshang Chemical Co., Ltd.», China) and thymol («Hunan Insen Biotech Co., Ltd.», China) (hazard class 4, SanPin 1.2.25.84-10) in group IV. Preparations containing the active ingredients amitraz and thymol + oxalic acid were sprayed onto drone brood in 2 repetitions with 7-day interval. The fluvalinate-containing strips were placed on both sides of the drone brood frame. The impact of antivarroal drugs was assessed based on sperm quality parameters and body weight of drones at the age of 26-30 days. Sperm was collected by artificially stimulating endophallus eversion in mature drones aged 26-30 days. The concentration of spermatozoa, motility, viability, morphology (defects and abnormalities) were assessed. When assessing the viability of spermatozoa by fluorescent microscopy, fluorochromes Hoechst 33258 (Pan-Eco, Russia) and PI (Khimmed, Russia) were used with a biological luminescent light-emitting diode microscope MICROMED 3LYUM LED (OOO Observational Instruments, Russia) with 400½ magnification. To determine the deformation of the heads of spermatozoa, rapid differentiated staining with a set of reagents Diahim-Diff-Quick (OOO "ABRIS + NPF", Russia) was used. Our results show that the treatment of bee colonies with acaricides affects the weight of drones. The decrease in body weight was significant when using fluvalinate and oxalic acids + thymol preparations, where the maximum weight of drones was 10-20 mg less (p function show_eabstract() { $('#eabstract1').hide(); $('#eabstract2').show(); $('#eabstract_expand').hide(); }