Host plant variation plastically impacts different traits of the immune system of a phytophagous insect

Abstract

Summary1. Host plant quality affects herbivorous insect performance and consequently their susceptibility to natural enemies. Recently, it has been hypothesized that the immune function of herbivorous insects can be altered by their host plant, thus generating variation in their susceptibility to entomopathogens. Previous studies testing this hypothesis provided contradictory outcomes, mainly as a result of the differences in methodology such as measuring a single-immune parameter rather than considering trade-off-mediated interactions between immune defence systems of the insect. Here, we hypothesized that plant-mediated changes in insect immunity could result from the alteration of physiological immune effectors of the herbivore evident as trade-offs. 2. Larvae of an inbred strain of the European grape berry moth Eupoecilia ambiguella were reared on five artificial diets each based on a different grape variety (Chardonnay, Chasselas, Gewurztraminer, Merlot, Riesling) and tested for changes in the baseline concentration of haemocytes, activities of the prophenoloxidase (PPO) system and of antimicrobial peptides of their haemolymph. Immune responsiveness of larvae across diets was also assessed by measuring changes in haemocyte concentration and activity of the PPO system after a bacterial immune challenge. 3. We found that variation among diets significantly affected immune defences of larvae. The alteration of the E. ambiguella immune system appears plastic and partly mediated by existing physiological trade-offs between immune pathways, at least between induced antibacterial defences and the PPO system. 4. These results clearly show that host plant quality can affect immune defences and potentially disease resistance of E. ambiguella and that these changes in immunity may also result from intrinsic trade-offs between immune defence systems in insects.

Thermal tolerance breadths among groundwater crustaceans living in a thermally constant environment

“…Readings were obtained every 30s at 490nm. Enzyme activity was measured as the slope of the reaction curve during the linear phase of the reaction (linear regression with R 2 >0.8) and reported as the increase in optical density (ΔOD) per minute and per microliter of haemolymph (Vogelweith et al, 2011).…”

Reduced plant nutrition under elevated CO2 depresses the immunocompetence of cotton bollworm against its endoparasite

“…The results of this study could have implications for the evolution of plant–herbivore–parasitoid interactions and emphasize the important role of the immune system and its variation based on host plant variation in bottom-up processes involving plants26. All in all, the role of elevated atmosphere CO 2 in the herbivore insect immune function is poorly known, definitely requiring further investigation.…”

Cloning and Functional Characterization of c-Jun NH2-Terminal Kinase from the Mediterranean Species of the Whitefly Bemisia tabaci Complex

“…Host plant can significantly influence the growth and condition of insects [19,35]. Previous experiments have examined the fecundity and longevity of adult whiteflies that were reared on cotton from egg to adult and transferred onto tobacco plants [36,37].…”

“…ERKs are involved in the regulation of meiosis, mitosis and post mitotic functions in differentiated cells, while JNK and p38 are critical for the stress-related signal transduction pathways conveying signals from the cell surface into the nucleus to initiate gene expression [15,16]. Previous studies found that JNK may be involved in cellular response to environmental stresses [17–19] and immune defense to virus and bacteria [16,20,21]. …”