The Life Histories of Two Temporarily Coexisting, Pond Dwelling Cladocerans

✍ Scribed by Gerhard Maier

• Book ID: 102871070
• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 642 KB
• Volume: 78
• Category: Article
• ISSN: 1434-2944
• DOI: 10.1002/iroh.19930780109

✦ Synopsis

Abstract

Investigations on the life histories of two cladocerans, Moina brachiata and Daphnia obtusa, in a small, nearly temporary pond in South Germany revealed that M. brachiata is better adapted to fluctuating environmental conditions; the species dominated from May to October. D. obtusa was present in spring and autumn/winter but disappeared completely during the summer months. Both species coexisted for extended periods in spring and autumn; abundance of D. obtusa was generally by an order of magnitute lower. Four periods of low water level were slightly preceded by or coincided with a decrease of clutch size, a decrease of the proportion of egg bearing females indicating that both species suffered from food shortage.

Laboratory investigations on life history parameters showed that the two species have different temperature tolerances and preferences. M. brachiata showed its highest reproductive success at 25 and 30°C but died at temperatures <15°C and ≥ 35°C. D. obtusa experienced a broader temperature range (2 to 25°C) but could not withstand temperatures ≥ 30°C. Short term starvation periods (3d) caused the death of M. brachiata females, while D. obtusa soon recovered and reproduced when being refed.

M. brachiata is a typical r‐species with early reproduction, rapid development, high population growth rates and a high tendency to produce resting eggs; D. obtusa pursues more the concept of k‐selection.