Figure 1. Effects of CO₂ on ovary activation of worker honeybees A).

In Experiment 1 Apis mellifera workers were narcotized on days 2 and 3 of adult life, and their ovaries examined after 4 hrs, 24 hrs, 48 hrs, and 96 hrs. The mean ovary score of narcotized bees was significantly lower than controls at 48 hrs (t-test, P = 0.005) and 96 hrs (t-test, P = 0.003). B) In Experiment 2 workers were narcotized on days 4 and 5 of adult life, and their ovaries examined after 4 hrs and 48 hrs. The mean ovary score of narcotized bees was significantly lower than controls at 48 hrs (t-test, P < 0.001).