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We sought to explain patterns in parasitism frequency of two specialist herbivores (Geometridae) by investigating the influence of plant diet as a source of variation in immune response variables important for defense against parasitism. Field collected caterpillars (Eois apyraria and Eois nympha) were assigned to one of two species in the plant genus Piper (Piperaceae): 1) a host species with high diversity of defensive chemistry, P. cenocladum C.DC., or 2) a host species with lower investment in chemical defense, P. imperiale C.DC. Hemolymph was extracted from fifth instar larvae, and immune strength measured unidimensionally using a phenoloxidase (PO) enzyme assay. Parasitism data came from 19 yr of accumulated host plant-caterpillar-parasitoid associations from a long-term rearing project at La Selva Biological Station in Costa Rica, where the experiment took place. We found that immunity was significantly weakened when caterpillars were reared on the host plant with higher phytochemical diversity (P. cenocladum). Moreover, host plants inducing a weak immune response hosted caterpillars with higher parasitism rates. We conclude that patterns in parasitism frequency can be partially explained by cascading effects of host plant traits. [ABSTRACT FROM AUTHOR]

Human IgA is comprised of two subclasses, IgA1 and IgA2. Monomeric IgA (mIgA), polymeric IgA (pIgA), and secretory IgA (SIgA) are the main molecular forms of IgA. The production of IgA rivals all other immunoglobulin isotypes. The large quantities of IgA reflect the fundamental roles it plays in immune defense, protecting vulnerable mucosal surfaces against invading pathogens. SIgA dominates mucosal surfaces, whereas IgA in circulation is predominately monomeric. All forms of IgA are glycosylated, and the glycans significantly influence its various roles, including antigen binding and the antibody effector functions, mediated by the Fab and Fc portions, respectively. In contrast to its protective role, the aberrant glycosylation of IgA1 has been implicated in the pathogenesis of autoimmune diseases, such as IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAVN). Furthermore, detailed characterization of IgA glycosylation, including its diverse range of heterogeneity, is of emerging interest. We provide an overview of the glycosylation observed for each subclass and molecular form of IgA as well as the range of heterogeneity for each site of glycosylation. In many ways, the role of IgA glycosylation is in its early stages of being elucidated. This chapter provides an overview of the current knowledge and research directions., (© 2021. The Author(s), under exclusive license to Springer Nature Switzerland AG.)