Hotter days, stronger immunity? Exploring the impact of rising temperatures on insect gut health and microbial relationships

Authors: SHIKANO, IKKEI - University Of Hawaii; Mason, Charles

Submitted to: Current Opinion in Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2023
Publication Date: 8/27/2023
Citation: Shikano, I., Mason, C.J. 2023. Hotter days, stronger immunity? Exploring the impact of rising temperatures on insect gut health and microbial relationships. Current Opinion in Insect Science. 59. Article 101096. https://doi.org/10.1016/j.cois.2023.101096.
DOI: https://doi.org/10.1016/j.cois.2023.101096

Interpretive Summary: Climate change has been implicated in the decline of insect populations worldwide. While there may be multiple aspects of climate change that can impact insects, temperature is among the most threatening. Extreme thermal shock in the form of heat waves can have cascading effects on individual insects. In this study, we addressed the impact of thermal shock in mediating immune-responses of insects and how that impacts relationships with entomopathogens and the gut microbiome. We summarized current literature, and discuss patterns and impacts. We also provide areas where knowledge is lacking and provide suggestions for future areas of research emphasis on temperature-pathogen-host interactions.

Technical Abstract: Climate change can generate cascading effects on animals through compounding stressors. As ectotherms, insects are particularly susceptible to variation in temperature and extreme events. How insects respond to temperature often occurs with respect to their environment, and a pertinent question involves how thermal stress integrates with insect capabilities to resolve interactions with gut microorganisms (microbiome and gut pathogens). We explore the impact of elevated temperatures and the impact of the host physiological response influencing immune system regulation and the gut microbiome. We summarize the literature involving how elevated temperature extremes impact insect gut immune systems, and how in turn that alters potential interactions with the gut microbiome and potential pathogens. Temperature effects on immunity are complex, and ultimate effects on microbial components can vary by system. Moreover, there are multiple questions yet to explore in how insects contend with simultaneous abiotic stressors and potential trade-offs in their response to opportunistic microbiota.