The relationship between maternal body size and clutch size, development time and egg mortality in Euchaeta norvegica (Copepoda: Calanoida) from Loch Etive, Scotland

Abstract

The relationship between maternal body size and egg clutch size in the marine calanoid copepod E. norvegica was quantified. Generally, larger females produced a greater volume and number of eggs than smaller ones, but some evidence suggested that smaller females produced a greater volume and number of eggs/unit body volume than larger ones. Possible causes of these variations are discussed. Egg mortality within the sac averaged 4%, with a range of 0-17%. The time taken by the eggs to hatch after egg laying was on average 18.7 days at 10.degree. C. A clutch of eggs was about 6% of wet body wt. The dry weight transferred to the eggs sometimes exceeded 25% of that remaining in the female body. Females kept in the laboratory were able to lay viable eggs after 3 wk isolation from males. This indicates a long storage life of the sperm after transfer to the females'' seminal receptacles.