Fig 1.
Hind tibia length as a function of host developmental stage.
Black: female A. certus; gray: male. S1: 1st stadium aphid, S2: 2nd stadium, S3: 3rd stadium, S4: 4th stadium, A: adult. Mean ± SE; shared letters indicate no significant difference.
Table 1.
Development time for Aphelinus certus on the various stages of soybean aphid separated by parasitoid sex with two-factor comparisons.
Fig 2.
Daily reproduction of parasitized and unparasitized soybean aphids.
(a) 3rd stadium, (b) 4th stadium, and (c) adult. Points plot least square means ± SE. Solid lines: unparasitized (control) aphids; dashed lines: parasitized aphids. Asterisks indicate significant differences between control and parasitized aphid reproduction on each day following parasitoid exposure (adjusted for multiple comparisons).
Table 2.
Values and sources of parameters used in the matrix model.
Fig 3.
Population dynamics predicted by the matrix model.
(a) Population dynamics of soybean aphid and A. certus. Black lines represent median densities with the interquartile (Q1–Q3) range shaded in gray. Solid line: soybean aphid (all living aphids); Dashed line: Aphelinus certus (all stages). Dotted horizontal line: economic threshold. (b) Histogram of peak aphid densities simulated from the model.
Fig 4.
Comparing measures of parasitism in model simulations.
Solid line: parasitism rate (d−1); dashed line: parasitism fraction (×100 = percent parasitism [%]); dotted line: mummy fraction.
Fig 5.
The effect of the parasitoid is shown as a percent reduction in peak host densities (solid line) as a function of (a) adult parasitoid lifespan, (b) the date of parasitoid colonization, (c) host-stage preference, and (d) mean daily temperature.