Is a starving host tastier? Reproduction in fleas parasitizing food-limited rodents

1. We hypothesized that food availability, and therefore body condition, of a rodent host, Meriones crassus, affects egg production and survival, and development time of preimago and adults of the first generation of the flea Xenopsylla ramesis. 2. Egg production was significantly higher in fleas parasitizing underfed than control animals. 3. Food availability for hosts affected survival of eggs and larvae produced by fleas on these rodents, but did not affect survival of pupae. More than twice the number of eggs from fleas on food-limited hosts survived than those from fleas on control rodents. Highest larval survival was recorded in fleas on rodents with 30% of maintenance energy intake. 4. Survival of new generation imagos was lowest in fleas from parents on hosts with the highest food limitation. By contrast, survival of parent fleas was highest on hosts offered 30% of maintenance energy intake. 5. Time of egg and larval development was longest on hosts consuming 30% of energy requirements for maintenance. By contrast, there was no difference in time to emergence in pupae from flea females on rodents from different treatments. Survival time under starvation of imago of the first generation was shortest in offspring of fleas that parasitized M. crassus offered the minimal amount of food. The opposite was true for parent fleas. 6. The results suggest nutritional and/or energetic cost of host resistance, measured as host-mediated parasite fitness loss, as well as possible adaptive stress-induced immunosuppression.