Effects of ageing and inbreeding on the reproductive traits in a cichlid fish II: the female perspective

Inbreeding and ageing have substantial impact on an individual’s fitness. Both can lead to an accumulation of deleterious alleles resulting in an addition of effects when inbreeding and age interact. The aim of this study was to investigate the separate and simultaneous effects of both factors on primary reproductive traits in females of the West African cichlid Pelvicachromis taeniatus, a socially monogamous cave breeder with biparental brood care that prefers kin as mating partner. We compared 1-year-old and 4-year-old lab-bred inbred and outbred females to reveal potential effects of inbreeding and age on ovary and egg traits. Inbreeding and degree of microsatellite heterozygosity had no significant effects on primary reproductive traits (ovary mass, gonadosomatic index, egg number, egg size, and egg color). However, inbred females were larger than outbred ones and individual heterozygosity correlated positively with female body size. The lack of inbreeding depression was expected considering the inbreeding preference of P. taeniatus, suggesting that the genetic load is purged from the examined population. Older females were larger than younger females and larger females had heavier ovaries containing a higher number and more intensively yellow colored eggs. The results indicate that age does not negatively affect reproductive traits in females of P. taeniatus. We discuss the results in comparison with male P. taeniatus in which negative ageing effects were found.