Egg size and clutch size in Pyrrhosoma nymphula (Sulzer) (Zygoptera: Coenagrionidae)

No significant relationships were found between either mean egg weight or clutch size and measures of female'skeletal size, when controlling for the effects of sample date. However, for particularly large clutches, abdomen size may have had a limiting effect on clutch size. Mean egg weight and clutch size were both significantly negatively correlated with sample date. Body size declined through the season, but females that visited the study ponds late in the season laid smaller clutches of smaller eggs than those that arrived early in the season, irrespective of size. Possible explanations for this are discussed. In particular, climatological factors may exert a strong influence on egg production and deposition in damselflies and dragonflies. Clutch size is likely to be closely related to the inter-clutch interval, and therefore to the pattern of sunny and cloudy days during a female’s reproductive lifespan, since reproductive activity occurs only on warm, sunny days.