The Relation between Temperature and Flashing Intervals in Adult Male Fireflies, Photinus pyralis

Field observations were made on the firefly Photinus pyralis (L.) to understand better the relation between temperature and the interval between successive flashes of flying adult males. A total of 1,334 measurements was made at 37 temperatures between 16.4° and 32.8° C.; the limits of the flash intervals were 3.3 and 13.2 seconds. The frequency distribution of intervals between successive flashes was skewed toward the longer flash intervals, with most of the means being greater than their respective medians within a temperature interval. The skewness increased as the temperature increased. Consequently a bias is introduced when simple means are used to summarize such data. In general the rate of flashing increased in a nonlinear manner with increasing temperature. The temperature coefficient (Q10) ranged from 1.6 to 2.1.