Rst(2)Lb^S animals cannot encapsulate the eggs of the avirulent (Av) or the virulent (V) strain of the parasitic wasp L.boulardi. The total haemocyte counts per mm³ (THC) and numbers of lamellocytes in unparasitised Rst(2)Lb^S and Rst(2)Lb^R larvae are not significantly different. The THC 6 hours after parasitisation with L.boulardi (either Av or V strains) is significantly higher than in unparasitised controls in both Rst(2)Lb^S and Rst(2)Lb^R larvae. The maximum THC is reached earlier (15 hours after parasitisation) in Rst(2)Lb^R larvae than in Rst(2)Lb^S larvae (24 hours after parasitisation). THC has decreased by 48 hours after parasitisation in all host-parasitoid strain combinations, but is still significantly higher than in controls. The number of lamellocytes per mm³ is significantly higher in both Rst(2)Lb^S and Rst(2)Lb^R larvae after parasitisation with L.boulardi (either Av or V strains) compared to unparasitised controls. The maximum number of lamellocytes is reached at 24 hours after infection in all host-parasitoid strain combinations. The V strain results in the formation of a high percentage of lamellocytes with altered morphology in both Rst(2)Lb^S and Rst(2)Lb^R larvae.

Animals homozygous for Rst(2)Lb^S are susceptible to infection by the hymenopteran parasite L.boulardi.

Rst(2)Lb^S larvae are susceptible to eggs of the parasitoid L.boulardi; an average of 2.9% of L.boulardi eggs deposited are encapsulated by larvae from the Rst(2)Lb^S strain. The resistant Rst(2)Lb^R allele is dominant over the susceptible Rst(2)Lb^S allele.