Document Type

Article

Publication Title

Journal of Animal Ecology

Publication Date

Spring 4-26-2022

Keywords

disease resistance, ecological immunity, immune assay, insect, pathogen, sexual dimorphism

Abstract

  1. Insects are important models for studying immunity in an ecological and evolutionary context. Yet, most empirical work on the insect immune system has come from phenotypic studies meaning we have a limited understanding of the genetic architecture of immune function in the sexes.
  2. We use nine highly inbred lines to thoroughly examine the genetic relationships between a suite of commonly used immune assays (haemocyte count, implant encapsulation, total phenoloxidase activity, antibacterial zone of inhibition and pathogen clearance) and resistance to infection by three generalist insect pathogens (the gram-negative bacterium Serratia marcescens, the gram-positive bacterium Bacillus cereus and the fungus Metarhizium robertsii) in male and female Gryllodes sigillatus.
  3. There were consistent positive genetic correlations between haemocyte count, antibacterial and phenoloxidase activity and resistance to S. marcescens in both sexes, but these relationships were less consistent for resistance to B. cereus and M. robertsii. In addition, the clearance of S. marcescens was genetically correlated with the resistance to all three pathogens in both sexes. Genetic correlations between resistances to the different pathogen species were inconsistent, indicating that resistance to one pathogen does not necessarily mean resistance to another. Finally, while there is ample genetic (co)variance in immune assays and pathogen resistance, these genetic estimates differed across the sexes and many of these measures were not genetically correlated across the sexes, suggesting that these measures could evolve independently in the sexes.
  4. Our finding that the genetic architecture of immune function is sex and pathogen specific suggests that the evolution of immune function in male and female G. sigillatus is likely to be complex. Similar quantitative genetic studies that measure a large number of assays and resistance to multiple pathogens in both sexes are needed to ascertain if this complexity extends to other species.

Funding Source

This research was funded by grants from the Australian Research Council (DP180101708) to J.H., and the National Science Foundation (IOS 16–54028) to S.K.S., B.M.S. and J.H.; C.L. was supported by Higher Degree Research Funds allocated by WSU School of Science and was the recipient of a PhD Scholarship granted by the Fonds de recherche du Québec—Nature et technologies. This research was supported in part by the U.S. Department of Agriculture, Agricultural Research Service. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.

Comments

First published in Journal of Animal Ecology (2022): https://doi.org/10.1111/1365-2656.13709

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction
in any medium, provided the original work is properly cited and is not used for commercial purposes.

Data are available from the Dryad Digital Repository https://doi.org/10.5061/dryad.79cnp5hxp (Hunt et al., 2022).

DOI

10.1111/1365-2656.13709

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