Parental Legacy in Insects: Variation of Transgenerational Immune Priming during Offspring Development
Figure 2
Transgenerational immune priming effects on the increase of immune activity of Manduca sexta offspring larvae and pupae one day after offspring immune challenge by PGN.
A) Increase of phenoloxidase (PO) activity and B) increase of antibacterial (AMP) activity (lysozyme activity equivalent, Micrococcus luteus) were measured in 4th instar larvae and 22-day-old pupae one day after offspring immune treatment. Female and male parents received a priming treatment in their pupal stage: Naive) untreated, PBS) control-injected with phosphate buffered saline, PGN) injected with peptidoglycan. If the symbol for offspring of naive parents is not visible, it is overlaid by another symbol. Increase of immune activity was measured as increase = (Activity after PGN treatment of the offspring)/(Mean activity of unchallenged offspring); value 1 is labelled by a line that indicates no change in immune activity after offspring challenge. Please note the comparable scales for increases which show the immunity and visualise the strong priming effects on offspring AMP activity, but the lack of effects on PO activity in the offspring. Mean values ± SE are given. N = 9 individuals of each developmental stage from each parental group. Means of absolute data of PGN- and PBS-treated offspring are shown in Table S5 in File S1. Differences between the parental priming treatments and the offspring developmental stages were compared by 2-way-ANOVA (Table 2). Statistical evaluation of priming effects on the increase of immunity after offspring immune challenge by PBS is shown in Table S6 in File S1.