Cellular and humoral immune interactions between Drosophila and its parasitoids

Authors: YANG, LEI - Zhejiang University; QIU, LI-MING - Zhejiang University; FANG, QI - Zhejiang University; Stanley, David; YE, GONG-YIN - Zhejiang University

Submitted to: Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2020
Publication Date: 8/10/2020
Citation: Yang, L., Qiu, L., Fang, Q., Stanley, D.W., Ye, G. 2020. Cellular and humoral immune interactions between Drosophila and its parasitoids. Insect Science. 28(5):1208-1227. https://doi.org/10.1111/1744-7917.12863.
DOI: https://doi.org/10.1111/1744-7917.12863

Interpretive Summary: Pest insects exert tremendous damage to human food crops on a global scale by spreading plant diseases and consuming crops. Invasive insect species costs a minimum of US$70 billion per year globally, although this may be a gross underestimate of total costs. Most insect pest control measures rely on insecticide treatments. These are responsible for a wide range of environmental issues, such as non-target killing of beneficial insects, such as pollinators, other invertebrates and vertebrate animals. Hence, insecticide treatments can lead to replacing one problem (pest insects) with another (environmental damage). Biological control of pest insect populations is a potential alternative pest management technology. This entails mass rearing and release of natural enemies, such as predatory or parasitic insect species that attack pest insects. Successful deployment of parasitic insect species can be curtailed by the effective immune responses of pest insects to parasite invasion, which creates a need to understand and manipulate insect immune responses to parasites. In this paper, we assemble current knowledge of immune response of the model insect, Drosophila melanogaster to its parasites. We detail insect immune responses to parasites and parasite mechanisms that disable such responses. This work will be used by scientists working around the globe on insect immune responses to parasite invasions and ultimately lead to new pest management technologies. Consumers will benefit from improve nutritional and food security.

Technical Abstract: The immune interactions occurring between parasitoids and their host insects, especially in Drosophila-wasp models, have long been the research focus of insect immunology and parasitology. Parasitoid infestation in Drosophila is counteracted by its multiple natural immune defense systems, which include cellular and humoral immunity. Occurring in the hemocoel, cellular immune responses involve the proliferation, differentiation, migration and spreading of host hemocytes and parasitoid encapsulation by them. Contrastingly, humoral immune responses rely more heavily on melanization and on the Toll, Imd and Jak/Stat immune pathways associated with antimicrobial peptides along with stress factors. On the wasps’ side, successful development is achieved by introducing various virulence factors to counteract immune responses of Drosophila. Some or all of these factors manipulate the host’s immunity for successful parasitism. Here we review current knowledge of the cellular and humoral immune interactions between Drosophila and its parasitoids, focusing on the defense mechanisms used by Drosophila and the strategies evolved by parasitic wasps to outwit it.