Factors influencing the egg laying of workers in a captive Bombus terrestris colony

Summary

• 1. The egg-laying behaviour of Bombus terrestris workers was studied in a captive colony by means of video recordings, in order to determine factors that make workers become egg-laying workers.

• 2. The size of a worker as a factor determining her to become a laying worker is only important for the workers that are born from the first batch of eggs. The sequence in which workers are born determines which workers are to become egg-laying workers and which are not.

• 3. Prospective egg-laying workers seek the proximity of the queen for a long period preceding their oviposition and tend not to participate in foraging activities. Workers who are pre-eminent in having interactions with the queen are the first to lay eggs. These workers compete with the queen for opportunities to lay eggs and finally push the queen off the comb.

• 4. There is strong competition between workers with regard to the acquisition of opportunities to lay eggs. As the ovaries of the workers develop, the interactions between workers and between workers and the queen become more openly agonistic. Egg-laying workers inhibit oogenesis in younger workers.