%0 Journal Article
%T Insect Host Defense Depends on the Balance Between Limiting Pathogen Burden and Tolerating the Physiological Cost of Infection
%A Mikko Lahtinen
%A Elina Salo
%A Juhani Virtanen
%J Entomological Research Letters
%@ 3108-639X
%D 2025
%V 5
%N 2
%R 10.51847/0ME8eIvWSO
%P 32-41
%X Insect infection outcomes are often interpreted through pathogen clearance, survival, or immune activation considered separately. This separation can obscure whether a host survives because it restricts pathogen burden, limits the damage associated with a given burden, or preserves function despite the physiological expense of defense. This article develops a proposed immunophysiological framework in which resistance, damage tolerance, immunopathology, and metabolic cost are treated as distinct but interacting dimensions of host defense. Evidence from Drosophila, mosquitoes, silkworms, and honey bees shows that pathogen control can depend on immune-cell metabolic reprogramming, systemic resource mobilization, mitochondrial state, and taxon-specific immune pathways, whereas survival can also improve without lower pathogen burden through tissue protection, damage repair, or metabolic support. Immune activity can itself generate tissue injury and energetic opportunity costs, preventing stronger activation from being interpreted automatically as better defense. The framework therefore treats pathogen burden, host damage, and physiological cost as jointly necessary observables rather than interchangeable proxies. It is proposed as a qualitative architecture for organizing experiments and predictions, not as a validated universal optimum across insects.
%U https://esvpub.com/article/insect-host-defense-depends-on-the-balance-between-limiting-pathogen-burden-and-tolerating-the-physi-867et9e1tplcvcy