Variation in performance and resistance to parasitism of Plutella xylostella populations

Authors: GOLS, RIETA - Wageningen University; DESURMONT, GAYLORD - European Biological Control Laboratory (EBCL); HARVEY, JEFFREY - Wageningen University

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2019
Publication Date: 9/11/2019
Citation: Gols, R., Desurmont, G.A., Harvey, J.A. 2019. Variation in performance and resistance to parasitism of Plutella xylostella populations. Insects. 10:293. https://doi.org/10.3390%2Finsects10090293.
DOI: https://doi.org/10.3390%2Finsects10090293

Interpretive Summary: Insect herbivores can adapt to local conditions, which can lead to subtle differences in the biology, ecology, and behavior of certain populations. Here we looked at an insect pest, Plutella xylostella, that is widespread worldwide, and we look how different populations of the pest originating from different geographic areas vary in the performance on a plant, Brassica rapa, and how they vary in resistance to a natural enemy, the parasitoid Diadegma semiclausum. Results revealed some population-specific differences in performance on the host plant and resistance to the natural enemy, showing the local adaptations of pests on plants can have consequences on their interactions with natural enemies.

Technical Abstract: Two major ecological factors determine the fitness of an insect herbivore. First, the ability to overcome plant resistance strategies (bottom-up effects) is vital because these will affect growth, development, survival and thus reproduction. Second, it is important to avoid or resist attack by natural enemies such as predators and parasitoids (top-down effects). Because of differences in selection pressure, variation may exist in host-plant adaptation and immunity against parasitism among populations of an insect herbivore. Here, we investigated variation in larval performance of different diamondback moth (Plutella xylostella) populations originating from Europe, Asia, Africa and the US, when feeding on a native Dutch plant species, Brassica rapa, as well as a P. xylostella population that has successfully switched host plant and is now adapted to feed on pea. In addition, we determined resistance to attack by the endoparasitoid Diadegma semiclausum originating from the Netherlands (where it is also native) and measured parasitoid performance as a proxy for variation in host suitability. Pupal mortality, immature development times and adult biomass of P. xylostella differed significantly across populations when feeding on the same host plant. In addition, parasitism success differed in terms of parasitoid adult emergence and their biomass, but not their development times.