The Influence of Body Weight on Semen Parameters in Apis mellifera Drones

Abstract

The quantity and quality of the honey bee drone semen have a significant determination on the performance of bee colonies. The existence of a smaller number of mature drones to participate in the mating of queens, as well as a sufficient number of drones but with poor quality semen can have serious implications for the productivity of bee colonies. Our study aimed to investigate the correlation between two body weight ranges of drones and semen parameters in the Buckfast honey bee, data that could be integrated into the optimization of instrumental insemination in been queens. Semen was collected from two groups of drones with different body weights (200–240 mg and 240–280 mg). Semen volume, semen concentration, motility, morphology and membrane integrity of spermatozoa were analyzed. The phenotype indicator related to body weight in correlation with the main semen parameters studied gives a weak influence or causality ratio. In drones with 240–280 mg body weight, a higher percentage of spermatozoa with abnormal morphology (>9.60%) was recorded, compared to drones with 200–240 mg body weight. The study reveals that a higher weight of honey bee drones is correlated with higher sperm concentration and total number of spermatozoa/ejaculate, with an increase in the percentage of spermatozoa with abnormal morphology.

Amwaprin is a honeybee sperm-binding protein that inhibits sperm motility and enhances sperm viability

“…Sperm lacking Amwaprin binding exhibited an altered sperm morphology, taking on a circular form. Considering the morphological changes in sperm under abnormal conditions, such as in hypoosmotic environments [29], this result indicates that the levels of Amwaprin on the sperm surface may in uence sperm morphology and lead to these changes. In this case, the levels of Amwaprin on the sperm surface are associated with sperm viability.…”

“…Sperm motility, an essential component of reproduction in honeybees [8, 29,34] and mammals [35], relies on ATP production by mitochondria located in the tail of sperm. In mammals, EPPIN exhibits inhibitory activity on sperm motility [16,36,37].…”

“…For the sperm viability assays, a suitable amount (approximately 4.6 × 10 6 sperms/ml of insect cell culture medium) of ejaculated sperm, determined using the hemocytometric method [29], was immediately placed in each well of a 96-well plate and treated with or without recombinant Amwaprin (300 ng) at 27°C for 1, 3, or 5 days. After the treatment, sperm staining was performed using SYBR 14 and propidium iodide and a LIVE/DEAD Sperm Viability Kit (Invitrogen).…”

“…Seminal uid from the drones (n = 9) was obtained following ejaculation, as described in a previous study [29]. Spermathecal uid from the mated queens (n = 6) was harvested by puncturing the spermathecae and centrifuged at 500 × g for 10 min to separate the sperm and spermathecal uid [6].…”