Fig 1.
The experimental design of choice tests and performance assays.
The host environment that the G0 insects experienced and the host environments they were offered in choice tests and that G1 insects were reared on in performance assays. In choice tests, adult G0 insects were transferred to an olfactometer connected to two host environments (see Fig 2). In performance assays, adult G0 insects were transferred to the same or alternative host environment immediately before nymph deposition or oviposition of G1. By transferring reproductive G0 adults, G1 nymphs had no prior exposure to their maternal environment.
Fig 2.
The olfactometer set up for choice tests.
(A) A diagram of the experimental set-up for the choice experiments and (B) Annotated photograph of an olfactometer displaying size measurements.
Fig 3.
Insect host environment preferences.
The percentage (%) of time spent in each half of the olfactometer chamber, exhibited by (A) pea aphids for bean (filled bars) or pea (open bars) plants, (B) parasitoid wasps for pea aphids on bean (dark grey bars) or on pea plants (light grey bars) in the plant comparison, and (C) parasitoid wasps for pea aphids on bean (dark grey bars) or potato aphids on tomato plants (light grey hatched bars) in the plant-aphid comparison. Values are means (± SEM) of n = 10 for all choice tests, except for G0 wasps reared on potato aphids on tomato plants when n = 8. *signifies bars are significantly different. For statistical summary see S1 Table.
Fig 4.
Performance of pea aphid offspring (G1).
(A) G1 intrinsic rate of population increase (Rm), (B) G2 nymph dry weight and (C) G1 survival. For (A) and (B), values are means (± SEM). Bars that share the same letter are not significantly different from each other. For (A), (B) and (C) the number of G1 aphid assays was n = 11 for G0 reared on bean and G1 reared on bean, n = 10 for G0 reared on bean and G1 reared on pea and G0 reared on pea and G1 reared on bean, and n = 9 for G0 reared on pea and G1 reared on pea.
Fig 5.
Leaf tissue nitrogen concentration of plants used in pea aphid performance assays.
Bean (shaded bars) and pea (hatched bars). Values are means (± SEM) of n = 12. Bars that share the same letter are not significantly different from each other.
Fig 6.
Performance of offspring (G1) parasitoid wasps in relation to G0 and G1 host environment.
Percentage of G1 wasps that emerged from their mummy and survived to adulthood in (A) the Plant Comparison (p>0.05) and (D) the Plant-Aphid Comparison; the sex of G1 wasps in (B) the Plant Comparison and (E) the Plant-Aphid Comparison; and the weight of G1 wasps in (C) the Plant Comparison and (F) the Plant-Aphid Comparison. Values are means (± SEM) of n = 10 for G0 wasps. nf and nm represent the number of females and males, respectively. For statistical summaries see S5 Table.
Fig 7.
Performance of mother (G0) parasitoid wasps in relation to the G0 and G1 host environment.
Quantified as the time (mins) taken for G0 wasps to oviposit into 30 aphids in (A) the Plant Comparison and (C) the Plant-Aphid Comparison and the number of G1 mummies formed by G0 wasps successfully ovipositing into aphids in (B) the Plant Comparison and (D) the Plant-Aphid Comparison. Values are means (± SEM) of n = 10. Bars that share the same letter are not significantly different from each other.