School of Science, Western Sydney University, Richmond, NSW, Australia.
School of Biological Sciences, Illinois State University, Normal, IL, USA.
J Anim Ecol. 2022 Jul;91(7):1471-1488. doi: 10.1111/1365-2656.13709. Epub 2022 May 3.
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. 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. 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. 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.
昆虫是研究生态和进化背景下免疫的重要模型。然而，大多数关于昆虫免疫系统的经验研究来自表型研究，这意味着我们对免疫功能的遗传结构在性别上的了解有限。我们使用九条高度近交系，彻底研究了一套常用免疫测定（血细胞计数、植入物包封、总酚氧化酶活性、抑菌区和病原体清除）与雄性和雌性 Gryllodes sigillatus 对三种普通昆虫病原体（革兰氏阴性菌 Serratia marcescens、革兰氏阳性菌 Bacillus cereus 和真菌 Metarhizium robertsii）感染的抵抗力之间的遗传关系。在两性中，血细胞计数、抗菌和酚氧化酶活性与对 S. marcescens 的抵抗力之间存在一致的正遗传相关性，但对 B. cereus 和 M. robertsii 的抵抗力的相关性则不太一致。此外，S. marcescens 的清除与两性对所有三种病原体的抵抗力具有遗传相关性。不同病原体物种之间的抗性遗传相关性不一致，表明对一种病原体的抗性不一定意味着对另一种病原体的抗性。最后，虽然免疫测定和病原体抗性有足够的遗传（协）方差，但这些遗传估计在性别之间存在差异，许多这些措施在性别之间没有遗传相关性，表明这些措施在性别之间可能独立进化。我们发现免疫功能的遗传结构具有性别和病原体特异性，这表明雄性和雌性 G. sigillatus 中免疫功能的进化可能很复杂。需要进行类似的定量遗传研究，在两性中测量大量的测定和对多种病原体的抗性，以确定这种复杂性是否扩展到其他物种。
