Age, pathogen exposure, but not maternal care shape offspring immunity in an insect with facultative family life

BMC Evolutionary Biology

Research Article

Maximilian Körner¹  Fanny Vogelweith¹  Susanne Foitzik¹  Joël Meunier² 

[1] Zoological Institute, Evolutionary Biology, Johannes-Gutenberg University of Mainz, Mainz, Germany;Zoological Institute, Evolutionary Biology, Johannes-Gutenberg University of Mainz, Mainz, Germany;Institut de Recherche sur la Biologie de l’Insecte, UMR CNRS 7261, François-Rabelais University of Tours, Tours, France;

关键词: Developmental stage;    Instar;    Family life;    Forficula auricularia;    Insect immunity;    Metarhizium;    Trade-off;   

DOI  :  10.1186/s12862-017-0926-y

 received in 2016-12-12, accepted in 2017-02-23,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundTo optimize their resistance against pathogen infection, individuals are expected to find the right balance between investing into the immune system and other life history traits. In vertebrates, several factors were shown to critically affect the direction of this balance, such as the developmental stage of an individual, its current risk of infection and/or its access to external help such as parental care. However, the independent and/or interactive effects of these factors on immunity remain poorly studied in insects.ResultsHere, we manipulated maternal presence and pathogen exposure in families of the European earwig Forficula auricularia to measure whether and how the survival rate and investment into two key immune parameters changed during offspring development. The pathogen was the entomopathogenic fungus Metarhiziumbrunneum and the immune parameters were hemocyte concentration and phenol/pro-phenoloxidase enzyme activity (total-PO). Our results surprisingly showed that maternal presence had no effect on offspring immunity, but reduced offspring survival. Pathogen exposure also lowered the survival of offspring during their early development. The concentration of hemocytes and the total-PO activity increased during development, to be eventually higher in adult females compared to adult males. Finally, pathogen exposure overall increased the concentration of hemocytes—but not the total-PO activity—in adults, while it had no effect on these measures in offspring.ConclusionsOur results show that, independent of their infection risk and developmental stage, maternal presence does not shape immune defense in young earwigs. This reveals that pathogen pressure is not a universal evolutionary driver of the emergence and maintenance of post-hatching maternal care in insects.

【 授权许可】

CC BY   
© The Author(s). 2017