The Effects of Temperature on Egg Development African Mayfly Povilla adusta (Ephemeroptera: Polymitarcidae)

Abstract

Egg masses were prepared from a packet of eggs of Povilla adusta Navas and incubated in the laboratory at constant temperatures and hatching success expressed by the logarithmic equation log Y = 0.14T + 1.42 (r2 = 0.028, P > 0.1). Hatching success was highest (84.85%) in eggs kept outside the incubator at laboratory temperature (33.2oC) followed by those incubated at 35oC (76.52%) and 30oC (65.46%) in that order. No hatching occurred in eggs incubated at 15oC, 20oC and 25oC. Minimum and mean incubated periods were the same at temperature at which eggs hatched. Hatching duration was short (1 - 2 days), which indicates synchronous hatching. A comparison of these results with previous findings suggests that Povilla adusta is warm adapted and as such, is confined to the tropical region in Africa where water temperatures are higher. Journal of Aquatic Sciences Volume 14, April 1999, pp. 47-50 KEY WORDS: Mayflies, temperature, egg development, distribution, Africa.