Maternal Trophic Status and Offpsring Phenotype in a Marine Invertebrate

Abstract

Offspring size variation in relation to maternal size and season is characteristic of a range of species living in seasonal environments. Little is known about the proximate mechanisms explaining the links between maternally driven variation in offspring phenotypes, for instance when mothers have different diets depending on their size or the season. Here, we use stable isotopes techniques to quantify size dependent and seasonal variations in diet in mothers of shrimp Palaemon serratus and explore possible links between maternal diet and phenotype of embryos and freshly hatched larvae. We found that larger females, which occur more frequently in winter, produce larvae with higher carbon and nitrogen content as well as higher percent carbon, than smaller mothers collected in winter. In addition, isotopic composition suggest that larger mothers collected in winter, were feeding at a higher trophic level, or on an enriched prey pool compared with smaller mothers collected in summer. Overall, there seems to be a strong association between offspring size and maternal diet, mediated by maternal size and/or season.

Figure 1

Mean and standard deviation of the carbon and nitrogen content for eggs, larvae and female muscles sampled over 2 seasons (winter vs. summer).

Figure 2

Relationships between female body size and the carbon and nitrogen percentage and the C/N ratio for the links females and eggs (a) and eggs and larvae (b) in summer and winter. Data of the link eggs-larvae (b) correspond to the second batch of females.

Figure 3

Relationships between female body size and the total carbon and nitrogen content for eggs and larvae per individual from the samples female-eggs (a) and eggs-larvae (b) in summer and winter. Data of the link eggs-larvae (b) correspond to the second batch of females.

Figure 4

Mean and standard deviation of the carbon and nitrogen isotopic signal (‰) of the eggs, freshly hatched larvae and female muscles sampled over 2 seasons (winter vs. summer).

Figure 5

Relationships between female body size and the carbon and nitrogen isotopic signal (‰) for the links between females and eggs (a) and eggs and larvae (b) in summer and winter. Data of the link between eggs-larvae (b) correspond to the second batch of females. Note that in the lower panels the scale is reversed so that δ¹³C increases downward.