Patterns of senescence in an insect: interactions between survival, reproduction and immunity

Started in october 2016

Defended the 9 june 2020

Funding: ANR Mater-Immunity

Supervisor: Yannick Moret ; cosupervisor: Thierry Rigaud

Abstract

Senescence is an almost universal process in multi-cellular organisms corresponding to an age-dependent decline of reproductive, immune and survival performance. Among the theories explaining such a phenomenon, the disposable soma theory of ageing proposes that senescence is caused by a resource allocation trade-off between reproduction and somatic maintenance. Hence, high early-life allocation to reproduction should be achieved at the expense somatic defences, including immunity, which would increase reproductive and actuarial senescence.

This thesis studied the relationships between reproduction, immunity and senescence in the mealworm beetle, Tenebrio molitor (Coleoptera, Tenebrionidae) by particularly focusing on the consequences of age-specific allocation in reproduction and immunity on senescence.

My results demonstrated clear evidence of patterns of intrinsic actuarial, reproductive and immune senescence in this insect. In addition, I have shown that early-life allocation to reproduction or to immunity always reduces late-life reproduction in females, while longevity is sometimes affected, thus, suggesting that T. molitor females favour longevity at the expense of reproduction. Furthermore, early-life allocation to reproduction or the immune function had contrasting consequences on immune effector systems, suggesting the occurrence of an immunosenescence revealed by both, the decline of some immune effectors and the deregulation of the activity of others. Together, these results are in agreement with the disposable soma theory of ageing.

Keywords

ageing, cost of reproduction, immuno-senescence, evolutionary biology

Jury

Christine Coustau, Institut Sophia Agrobiotech – reviewer
Jean-François Lemaitre, université Claude Bernard Lyon 1 – reviewer
Sophie Beltran-Bech, université de Poitiers – examiner
Bruno Faivre, université Bourgogne Franche-Comté – examiner
Yannick Moret, université Bourgogne Franche-Comté – supervisor
Thierry Rigaud, université Bourgogne Franche-Comté – cosupervisor

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Patterns of senescence in an insect: interactions between survival, reproduction and immunity

Started in october 2016

Defended the 9 june 2020

Funding: ANR Mater-Immunity

Supervisor: Yannick Moret ; cosupervisor: Thierry Rigaud

 

Abstract

Senescence is an almost universal process in multi-cellular organisms corresponding to an age-dependent decline of reproductive, immune and survival performance. Among the theories explaining such a phenomenon, the disposable soma theory of ageing proposes that senescence is caused by a resource allocation trade-off between reproduction and somatic maintenance. Hence, high early-life allocation to reproduction should be achieved at the expense somatic defences, including immunity, which would increase reproductive and actuarial senescence.

This thesis studied the relationships between reproduction, immunity and senescence in the mealworm beetle, Tenebrio molitor (Coleoptera, Tenebrionidae) by particularly focusing on the consequences of age-specific allocation in reproduction and immunity on senescence.

My results demonstrated clear evidence of patterns of intrinsic actuarial, reproductive and immune senescence in this insect. In addition, I have shown that early-life allocation to reproduction or to immunity always reduces late-life reproduction in females, while longevity is sometimes affected, thus, suggesting that T. molitor females favour longevity at the expense of reproduction. Furthermore, early-life allocation to reproduction or the immune function had contrasting consequences on immune effector systems, suggesting the occurrence of an immunosenescence revealed by both, the decline of some immune effectors and the deregulation of the activity of others. Together, these results are in agreement with the disposable soma theory of ageing.

 

Keywords

ageing, cost of reproduction, immuno-senescence, evolutionary biology

 

Jury

Christine Coustau, Institut Sophia Agrobiotech – reviewer
Jean-François Lemaitre, université Claude Bernard Lyon 1 – reviewer
Sophie Beltran-Bech, université de Poitiers – examiner
Bruno Faivre, université Bourgogne Franche-Comté – examiner
Yannick Moret, université Bourgogne Franche-Comté – supervisor
Thierry Rigaud, université Bourgogne Franche-Comté – cosupervisor

extrait:

lien_externe:

titre_these:

Patrons de sénescence : interactions entre survie, reproduction et immunité chez un insecte

date_de_debut_these:

octobre 2016