Integrated effects of thermal acclimation and challenge temperature on cellular immunity in the plusiine moth larvaeChrysodeixis eriosoma(Lepidoptera: Noctuidae)

Abstract

Temperature is one of the most influential factors for animals. The acclimation (rearing) and challenge temperatures are often more important than the given temperature per se. These effects on physiological responses have been known, but not well understood on immune responses. Here, we investigated the integrated effects of rearing and challenge temperatures on haemocyte populations in larvae of a plusiine moth, Chrysodeixis eriosoma. We hypothesize that the haemocyte concentration is decreased (increased) at higher (lower) temperatures from rearing temperatures and that the proportions of haemocyte types exhibit directional changes at higher (lower) temperatures to compensate for immune reactions. We expect that increasing (decreasing) the challenge temperature from the rearing temperature enhances (reduces) phagocytic activity. We found that higher temperatures slightly decreased the haemocyte concentration. We detected small changes in the proportions of haemocyte types among rearing temperatures, but the changes were non‐directional and most of them were statistically insignificant. We also found the integrated effects only with increases in the challenge temperatures, which resulted in increased phagocytosis, whereas no apparent reactions were detected with decreases in the challenge temperatures. Our results show that the haemocyte concentration is significantly affected by the rearing temperature, which implies that haematopoiesis depends on the ambient temperature. We discuss some adaptive and non‐adaptive components for the positive integrated effects of increases in the challenge temperatures. We also discussed the obtained non‐responsiveness in the integrated effects with decreases in the challenge temperatures.

The Development of New Methods to Stimulate the Production of Antimicrobial Peptides in the Larvae of the Black Soldier Fly Hermetia illucens

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