Maternal investment in the offspring of Pseudodiaptomus annandalei under nitrogen deficiency

Allocation of resources to reproduction varies with food condition experienced by an organism and potentially influences the future growth of the offspring. In this study, adult females of the copepod Pseudodiaptomus annandalei were fed diets with different carbon: nitrogen ratios (atomic C:N ratio=4.8, 20.1, and 28.7 for HN, MN and LN, respectively), and the allocation of elements and fatty acids (FAs) in the offspring, as well as naupliar development of the offspring were measured.Egg production rate remained constant under the different dietary N conditions (3.2–3.4eggsd−1). Mother copepod reduced both offspring size and investment of nutrients per progeny under N-deficiency. In NI offspring under N-deficiency, body size and DHA content declined significantly by 11–39% and 52–55%, respectively. There was also a decreasing trend in their N content. Naupliar development was delayed in small-sized offspring originating from maternal MN and LN dietary treatments, with prolonged naupliar duration and shorter body length at Stage CI. Growth recovery occurred only in offspring originating from maternal MN treatment when fed HN food. Generally, DHA content of NI nauplii correlated negatively with the naupliar duration. On the other hand, N content of NI nauplii correlated moderately with the naupliar duration and body length at Stage CI depending on postnatal N condition. These results suggest that performance of offspring was affected by maternal investment of DHA and N. The finding that adult female P. annandalei traded offspring quality for fecundity under N-deficiency points to the rule of selfish maternal effect. This is an adaptation to the N-deficiency in respect to maternal fitness, but not offspring fitness. It is implied that the influence of N-deficiency may carry over to the successive generation and impair population development in this species.