Seasonal synchronization of emergence in Dolania americana (Ephemeroptera: Behningiidae)

Abstract

This paper summarizes factors regulating seasonal emergence of Dolania americana in the Blackwater River, Florida, U.S.A. Emergence is temperature-dependent, and emergence on a given day can be predicted from the period of nymphal maturation and the pattern of temperature on previous mornings. Development of the last two nymphal instars follows a pattern that can be interpreted linearly or by day-degree summations. Increases in water temperature at time of emergence (dawn) on the previous day provide the best correlation with emergence. Different responses to temperature events that cue emergence probably result from the effects of different temperature regimes in which the different populations develop. In experiments, males emerged equally 1 and 2 days after increases in the daily low water temperature, while females emerged more frequently after 2 days of increasing temperatures.