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Maternal dopamine exposure provides offspring starvation resistance in Daphnia
  • +2
  • Semona Issa,
  • Safa Chaabani,
  • Alexandros Asimakopoulos,
  • Veerle Jaspers,
  • Sigurd Einum
Semona Issa
Norwegian University of Science and Technology

Corresponding Author:semona.issa@landbruksdirektoratet.no

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Safa Chaabani
Norwegian University of Science and Technology
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Alexandros Asimakopoulos
Norwegian University of Science and Technology
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Veerle Jaspers
Norwegian University of Science and Technology
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Sigurd Einum
Norwegian University of Science and Technology
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Abstract

The neurotransmitter dopamine has been shown to play an important role in modulating behavioural, morphological and life-history responses to food abundance. However, costs of expressing high dopamine levels remain poorly studied and are essential for understanding the evolution of the dopamine system. Negative maternal effects on offspring size from enhanced maternal dopamine levels have previously been documented in Daphnia. Here, we tested whether this translates into fitness costs in terms of lower starvation resistance in offspring. We exposed Daphnia magna mothers to aqueous dopamine (2.3 mg/L or 0 mg/L for the control) at two food levels (ad libitum versus 30% ad libitum) and recorded a range of maternal life history traits. The longevity of their offspring was then quantified in the absence of food. In both control and dopamine treatments, mothers that experienced restricted food ration had lower somatic growth rates and higher age at maturation. Maternal food restriction also resulted in production of larger offspring that had a superior starvation resistance, compared to ad libitum groups. However, although dopamine exposed mothers produced smaller offspring than controls at restricted food ration, these smaller offspring survived longer under starvation. Hence, maternal dopamine exposure provided an improved offspring starvation resistance. We discuss the relative importance of proximate and ultimate causes for why D. magna may not evolve towards higher endogenous dopamine levels despite the fitness benefits this appears to have.
17 Jan 2022Submitted to Ecology and Evolution
17 Jan 2022Submission Checks Completed
17 Jan 2022Assigned to Editor
20 Jan 2022Reviewer(s) Assigned
14 Feb 2022Review(s) Completed, Editorial Evaluation Pending
22 Feb 2022Editorial Decision: Revise Minor
07 Mar 20221st Revision Received
07 Mar 2022Submission Checks Completed
07 Mar 2022Assigned to Editor
07 Mar 2022Review(s) Completed, Editorial Evaluation Pending
15 Mar 2022Editorial Decision: Accept