Effects of paternal phenotype on offspring fitness in rohu (Labeo rohita)

Abstract

In many species, males influence phenotypic traits in their offspring through non-genetic paternal effects. Such effects can represent a form of paternal investment to maximize offspring fitness. Here, I have conducted an experiment to explore whether bigger males have better reproductive performance and thereby, produce the best quality offspring. In the experiment, I have three male size groups, such as 1) bigger males (3-5 kg), 2) medium males (1-2 kg), and 3) smaller males (less than 1 kg). There were 20 males in each group, and some common females were taken to conduct this study. The experiment was designed in such a way that enabled to measure the variation of some selected reproductive traits and then to assess offspring fitness traits after rearing them up to two weeks under controlled laboratory conditions. The results have revealed that both bigger and medium size males produced significantly higher amount of sperm than smaller ones. In case of hatching rate, bigger males produced significantly higher number of hatchlings than smaller ones, while no variations have been found between big and medium, and also medium and small male groups. No significant difference was observed in hatchlings deformation rate among the experimental male groups. Finally, the study has revealed that bigger fathers' offspring had significantly higher survival rate, obtained larger standard length and body area than medium and smaller father groups. These results suggest that parents can be selected to maximize the offspring fitness traits which would be an important message to the associated aquaculture stakeholders.