Common biomarkers of vertebrate senescence respond to age variation in the invertebrate Armadillidium vulgare

Senescence, the decline of physiological parameters with increasing age, is a quasi-ubiquitous phenomenon in the living world. However, the observed patterns of senescence can markedly differ between across species and populations, between sexes and even among individuals. To identify the drivers of this variation in senescence, experimental approaches are essential and involve the development of tools and new study models. In this context, we tested whether biomarkers of vertebrate ageing could be used to study senescence in a very promising invertebrate model of ageing: the common woodlouse Armadillidium vulgare. More specifically, we looked for the effect of age in woodlouse on three well established physiological biomarkers of ageing in vertebrates: immune cells (cell size, density and viability), β-galactosidase activity, and Telomerase Reverse Transcriptase (TERT) (essential subunit of the telomerase protein) gene expression. We found that the size of immune cells was higher in older individuals, whereas their density and viability decreased, and that the β-galactosidase activity increased with age, whereas the Telomerase Reverse Transcriptase (TERT) gene expression decreased. These findings demonstrate that woodlouse display age-related changes in biomarkers of vertebrate senescence, with different patterns depending on gender. Thus, the tools used in studies of vertebrate senescence can be successfully used in studies of senescence of invertebrates such as the woodlouse. The application of commonly used tools to new biological models offers a promising approach to assess the diversity of senescence patterns across the tree of life.