Sperm Quality Assessment in Honey Bee Drones

Abstract

The quality of honey bee drone semen is relevant in different contexts, ranging from colony productivity to pathology, toxicology and biodiversity preservation. Despite its importance, considerably less knowledge is available on this subject for the honey bee when compared to other domestic animal species. A proper assessment of sperm quality requires a multiple testing approach which discriminates between the different aspects of sperm integrity and functionality. Most studies on drone semen quality have only assessed a few parameters, such as sperm volume, sperm concentration and/or sperm plasma membrane integrity. Although more recent studies have focused on a broader variety of aspects of semen quality, some techniques currently used in vertebrates, such as computer-assisted sperm analysis (CASA) or multiparametric sperm quality testing, still remain to be developed in the honey bee. This may be attributed to the particular sperm morphology and physiology in this species, requiring the development of technologies specifically adapted to it. This article reviews the present knowledge of sperm quality in honey bee drones, highlighting its peculiarities and proposing future lines of research.

Pesticide risk assessment in honeybees: Toward the use of behavioral and reproductive performances as assessment endpoints

“…Thus, the next step would be to simplify measurement methods. The recent development of cytometry flux methods to determine spermatozoa number and viability in either queen spermatheca or drones has led to more accurate and robust quantification (Pettis et al, 2016;Tofilski et al, 2012;Yániz et al, 2020). Such endpoints notably have the advantage of communicating actual or future queen quality.…”

Factors Influencing the Reproductive Ability of Male Bees: Current Knowledge and Further Directions

“…Most studies related to the cryopreservation of frozen semen regard acrosomal integrity as an indicator of digestion of the zona pellucida and the fusion ability of sperm [35,36]. Yaniz and colleagues summarized most of the parameters and several kinds of methods for the analysis of semen quality in honeybees [37]. Poor male reproductive ability may affect health and productivity by influencing queen fecundity, which determines subsequent worker behavioral or physiological traits and is influenced by semen fluid and viable sperm [38].…”

Prospects in Connecting Genetic Variation to Variation in Fertility in Male Bees

“…Other proxies could provide a more precise measurement of sperm quality. For example, mitochondrial activity, acrosome reaction, DNA fragmentation, and sperm motility could be used [143]. Mitochondrial activity measures sperm metabolism and energetics.…”

“…The sperm may be viable but has a reduced capacity to fertilize eggs [144]. DNA fragmentation detects damaged DNA in the sperm [143]. DNA damage in sperm can occur for several reasons, such as environmental variation.…”