Comparative assessment of motility and concentration of spermatozoa of honey bee drones by traditional microscopy and CASA methods

The study of sperm quality in honey bee drones is a complex analysis that requires evaluating multiple sperm characteristics. Such analysis is currently performed via traditional ocular microscopy. There is also a computer-aided sperm analyses (CASA) method for assessing sperm quality. The CASA method is most widely used in the livestock industry. The aim of our study was to determine the differences in the assessment of motility and sperm concentration of honey bee drones by ocular microscopy and CASA. Sperm was collected by artificial stimulation of endophallus eversion in sexually mature 22-30-day-old honey bee drones using SCHLEY-System model 1.04 artificial insemination equipment. By the CASA method, the qualitative characteristics of the sperm were evaluated using Sperm Class Analyzer (SCA) MICROPTIC S.L. Spermatozoa were evaluated for motility and concentration. Differences between study groups were compared using Student’s t-test for independent samples. The results of the study demonstrate the possibility of assessing the motility and concentration of spermatozoa of honey bee drones by the CASA method in combination with phase-contrast microscopy (Ph+). In CASA evaluation, sperm concentration averaged 4.6 million/μl, which was 0.4 million less than the figure obtained via conventional ocular microscopy and was not a significant difference. Total sperm motility assessed by the CASA method was significantly different (t = 2.8) from visual assessment by an average of 16.7%. In particular, the determination of total sperm motility of honey bee drone spermatozoa via ocular microscopy was affected by the subjective evaluation of the operator