Relationship between semen quality and performance of instrumentally inseminated honey bee queens

Abstract

ing: assessing semen quality based on spermatozoal motility [12,21], counting the number of spermatozoa in the spermatheca (semen storage organ) of an instrumentally inseminated queen [2,6,9,11,12], and comparing the proportion of worker pupae (from fertilized eggs) to drone pupae (unfertilized eggs) produced by an inseminated queen [6,9,18,23]. Harbo [7] also measured egg hatching rate. INTRODUCTIONThe development of a practical means to store honey bee (Apis mellifera L.) semen would enhance our ability to select and maintain superior honey bee stocks. A number of storage techniques have been tried with some success, using both ultra-cold freezing and non-frozen approaches (reviewed in [22] Abstract -Techniques to effectively store honey bee semen must meet some minimally acceptable level of spermatozoa survival. To determine this level, honey bee queens were inseminated using various mixes of fresh and freeze-killed semen, and were allowed to lay eggs in small colonies for three weeks. The queens receiving all freeze-killed spermatozoa (0% fresh) had no spermatozoa in their spermathecae, and produced only drone pupae (unfertilized eggs). The proportions of live and dead spermatozoa (determined by dual fluorescent staining) in the spermathecae of queens receiving 25 to 100% fresh semen were not significantly different at 27 days post-insemination. Queens receiving 50% fresh semen or more produced only worker pupae (all eggs were fertilized). Therefore, a program to improve storage of semen should only have to reach survival levels of 50% of the spermatozoa to have functional semen.Apis mellifera / spermatheca / brood pattern / spermatozoa viability / sperm storage

Comparison studies of instrumentally inseminated and naturally mated honey bee queens and factors affecting their performance

“…Oertel (1940) and Jhajj et al (1992) reported that the age queens generally take mating flights is between 4 and 13 days post-emergence. Virgin queens can be instrumentally inseminated when they are a few days to several months old (Tarpy and Fletcher, 1998;Collins, 2000a). However, the age at which queens are mated affects their performance.…”

“…The spermathecal fluid contains proteins, sugars and antioxidants, and the surrounding tracheal net provides oxygen (Koeniger, 1986;Phiancharoen et al, 2004). The physical and chemical properties of diluents; pH, osmolarity and nutrients, and the handling methods can enhance or reduce sperm cell survival (Verma, 1978;Moritz, 1984;Harbo, 1986b;Collins, 2000a).…”

“…Collins (2000a) and Lodesani et al (2004) showed that sperm cells are selected for quality during migration into the spermatheca. Queens inseminated with 50% live and 50% dead sperm cells produced viable laying queens (Collins, 2000a). Motility, previously assumed as a characteristic to measure semen quality, is not an accurate indicator (Collins, 2006).…”

Standard methods for instrumental insemination of Apis mellifera queens

“…Current techniques using centrifugation result in a high percentage of damaged spermatozoa, although 50% viability of spermatozoa is sufficient to produce normal brood patterns (Collins, 2000). Semen is very dense, tends to clump, and the long, fragile tails of spermatozoa are subject to damage during processing and some components of the seminal fluid are removed.…”

A scientific note on amoeboid movement of honey bee semen

“…The semen does not inflate the spermatheca but replaces the fluid present there (Dade 1994). Several mechanisms of the transfer have been suggested including semen pump (Bresslau 1905), contraction of oviducts (Ruttner & Koeniger 1971) and active spermatozoa movement (Collins 2000). Amoeboid movement of semen could be critical to the transfer of sperm from oviducts to the spermatheca because it would allow the semen to spread into any air pocket formed at the entrance to the spermathecal duct.…”