Fig. 1.

Percentage (+SE) of individuals having demonstrated active flight (a) and average delay (+SE) in seconds before active flight (b) at 12, 15, and 18°C after a 10-min observation period for the American hoverfly, Eupeodes americanus (n = 69 at 18°C, n = 71 at 15°C, n = 62 at 12°C) and the silverfly, Leucopis glyphinivora (n = 53 at 18°C, n = 54 at 15°C, n = 51 at 12°C). Treatments with a different letter and an asterisk are significantly different (ANOVA, P < 0.05). Uppercase letters are for the American hoverfly, and lowercase letters are for the silverfly.