3.2. Semen collection
Semen is collected directly from the endophallus of many drones into a syringe and stored in glass capillary tubes. The amount and consistency of semen obtained from each drone varies and depends on skill and experience. Generally, each drone will yield approximately 1µl of semen. The standard volume of semen to inseminate one queen is ~8 to 12 µl.
Maintain sanitary conditions, as drones often defecate during eversion. It is recommended to have a paper towel readily available to wipe drone faeces. Although less common, queens may also defecate. Discard the queen if this happens during the procedure.
Procedure for collecting semen:
- After assembly of the syringe, collect an air space (~5 µl) to separate the saline and semen column in the syringe. Then collect a small drop of saline into the glass tip (~2 µl). This will be the last fluid to be injected into the last queen inseminated, which will help wash any remaining semen adhering to the capillary walls out of the tip and into the queen.
- Collect another small air space and collect a small drop ( 0.5 µl) of saline in the syringe tip (Fig. 9). Use the drop of saline to make contact with the semen on the endophallus of the first drone.
- Skim the semen off the mucus layer and draw it into the syringe (Fig.
a. Avoid collecting the viscous mucus layer at all costs. If resistance is felt, back off or expel any mucus in the tip. Excess mucus in the tip can leave it clogged (Fig. 11).
- Repeat Step 3 until the total desired amount of semen is collected.
a. Expel a small drop of semen from the syringe tip on to the semen load of the next drone and draw semen into the syringe (Fig. 12)
b. Avoid collection of air bubbles and additional saline in the semen column. The column of semen should be uniform in colour and density.
c. Between semen loads, keep the tip moist with saline to prevent drying, taking care not to excessively dilute the semen. Drone semen quickly dries and the sperm die when exposed to air.
Fig. 9. Collecting semen into the syringe. Collect an air space to separate the saline and semen column in the syringe. After the air space, collect a small drop of saline in the syringe tip to make contact with the semen on the endophallus of the first drone.
Fig. 10. Collecting semen. Skim the semen, a marbled tan colour, off the underlying layer of viscous white mucus and draw this into the syringe.
Fig. 11. Accidental collection of mucus into the syringe. Avoid collecting the viscous mucus layer as pictured here. If resistance is felt, back off or expel any mucus in the tip to avoid clogging the tip.
Fig. 12. Collecting semen from subsequent drones. To repeat the process of semen collection from the next drone, expel a small drop of semen from the syringe tip onto the semen load of the next drone and draw this into the syringe.