Abstract : Nutritional quality during early life can affect learning ability and memory retention of animals. Here we studied the effect of resource
quality gained during larval development on the learning ability and memory retention of 2 sympatric strains of similar genetic background
of the parasitoid Trichogramma brassicae: one uninfected and one infected by Wolbachia. Wolbachia is a common arthropod
parasite/mutualistic symbiont with a range of known effects on host fitness. Here we studied, for the first time, the interaction between
resource quality and Wolbachia infection on memory retention and resource acquisition. Memory retention of uninfected wasps was
significantly longer when reared on high quality hosts when compared to low quality hosts. Furthermore, uninfected wasps emerging
from high quality hosts showed higher values of protein and triglyceride than those emerging from low quality hosts. In contrast, the
memory retention for infected wasps was the same irrespective of host quality, although retention was significantly lower than uninfected
wasps. No significant effect of host quality on capital resource amount of infected wasps was observed, and infected wasps
displayed a lower amount of protein and triglyceride than uninfected wasps when reared on high quality hosts. This study suggests
that the nutritional quality of the embryonic period can affect memory retention of adult wasps not infected by Wolbachia. However, by
manipulating the host’s obtained capital resource amount, Wolbachia could enable exploitation of the maximum available resources
from a range of hosts to acquire suitable performance in complex environments.