Modulation of immune priming across developmental stages and sexes in Tenebrio molitor
Year: 2026
Type: article
Abstract: Insects deploy both constitutive and inducible immune defences to cope with pathogen exposure. In some invertebrates, inducible “immune priming” can enhance survival upon secondary infection, but its modulation across life-history contexts remains poorly understood. We investigated how developmental stage, sex, and reproductive status affect immune priming in the mealworm beetle Tenebrio molitor. Larvae and adults, males and females, and adults of differing reproductive status were subjected to bacterial priming or sham treatments, followed by a secondary infection. Survival was recorded, and haemocyte counts, phenoloxidase activity, and antibacterial capacity were quantified before and after priming to assess immune responses. Larvae exhibited higher survival than adults, despite lower baseline haemocyte counts and phenoloxidase activity. Priming improved survival in infected individuals, with effects more pronounced in adults. Physiologically, priming increased plasmatocyte counts, phenoloxidase activity, and antibacterial activity in adults, whereas larvae showed limited immune modulation. Neither sex nor reproductive status significantly influenced priming efficacy, although infected females had slightly higher mortality than males. Our results indicate that immune priming in T. molitor is developmentally constrained: larvae rely on strong constitutive defences, while adults benefit from inducible immune responses. These findings highlight the importance of life-history stage in shaping the expression and functional outcomes of insect immunity, and suggest that the efficacy of immune priming depends on immune regulation and functional quality rather than absolute investment.
Source: Entomologia Generalis
Language: English
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7204969869