Sex discriminatory effect of the acanthocephalan Acanthocephaloides propinquus on a gobiid fish Gobius bucchichii

Most studies which aim of detecting effects of parasites on fish show that intermediate stages of parasites affect their host while adult parasites ar e usually less virulent in the final host. We studied the effect of the aca nthocephalan Acanthocephaloides propinquus on one of its final hosts, the f ish Gobius bucchichii. This study showed that the adult parasites affect ho st fitness, Moreover, our results showed that at the some level of infectio n in male and female gobiids, the female's reproductive success was negativ ely correlated to parasite abundance while the male's reproductive success was not, The negative effects on females includes reductions in gonado-soma tic index and egg production, We hypothesized that it might be more difficu lt for females to compensate the cost of parasitism because of the very hig h cost of egg production, We discussed these results in terms of host popul ation regulation.