Lack of trade-offs in host offspring produced during fecundity compensation

Host-parasite coevolution may result in life-history changes in hosts that can limit the detrimental effects of parasitism. Fecundity compensation is one such life-history response, occurring when hosts increase their current reproductive output to make up for expected losses in future reproduction due to parasitic infection. However, the potential trade-offs between this increase in quantity and the quality of offspring have been relatively unexplored. This study uses the trematode, Schistosoma mansoni, and its snail intermediate host, Biomphalaria glabrata, to better understand how this host life-history response, fecundity compensation, impacts host reproduction. Measures of host reproductive output as well as offspring hatching success and survival were collected to assess the reproductive consequences of infection. Infected snails exhibited fecundity compensation by increasing the number of eggs laid and the overall probability of laying eggs compared to uninfected snails. Parental infection status did not play a significant role in hatching or offspring survival to maturity. Offspring from a later reproductive bout demonstrated a higher hatching success rate. Overall, the lack of an apparent trade-off between quantity and quality of offspring suggests that infected parental snails invest more resources towards reproduction not only to increase reproductive output, but also to maintain the fitness of their offspring, possibly at the expense of their own longevity.