Influence of Nutritional Stress on Female Allocation and Somatic Growth in the Simultaneously Hermaphroditic Polychaete Worm <i>Ophryotrocha diadema</i>

Abstract

Hermaphrodites are characterized by plastic sex allocation, by which they adjust their allocation of reproductive resources according to mating opportunities. However, since the plasticity of sex allocation is influenced by environmental conditions, it may also be affected by species-specific life–history traits. In this study, we explored the trade-off between nutritional stress due to food deficiency and the investment of resources in female allocation and somatic growth in the simultaneously hermaphroditic polychaete worm, Ophryotrocha diadema. To achieve this, we exposed adult individuals to three food supply levels: (1) ad libitum—100% food supply, (2) intense food deficiency—25% food resources, and (3) extreme food deficiency—0% food resources. Our findings show a progressive decrease in female allocation in the numbers of cocoons and eggs and in body growth rate of O. diadema individuals as the level of nutritional stress increased.

Keywords

• egg cocoons
• marine polychaetes
• food deprivation
• female investment
• life–history traits