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Experimental manipulation of social status in a bat: impact on oxidative stress and sperm quality

Last update: : Wednesday 4 November 2015, by Catherine Berger

Par : Magalie Meniri, University of Neuchatel
Date : Jeudi 3 décembre 2015 à 13h30
Lieu : IPHC, Amphithéâtre Grünewald, bâtiment 25

Oxidative stress has been proposed to be a universal mechanism underlying major life history trade-offs. Indeed, reactive oxygen species represent a major constraint for all organisms. Sperm cells are especially vulnerable to oxidative stress, which will reduce male fertility. Therefore, antioxidant allocation is expected to have a major role in male reproductive tactics.
Short tailed fruit bats (Carollia perspicillata) exhibit two alternative reproductive tactics, with harem males defending a territory, by opposition to males sneaking copulations. According to sperm competition models, sneakers are expected to invest relatively more ressources such as antioxidants in their ejaculate, leading to enhanced sperm quality, to compensate for a lower access to females.

To test the hypothesis that males accord their sperm quality to their social status by adjusting their antioxidant allocation, we experimentally manipulated male social status. We monitored the males’ redox profiles through a set of biomarkers in both blood and sperm. Sperm quality was assessed using Computer Assisted Sperm Analyses (CASA). We examined the expected adjustements in sperm quality at two different time scale: quickly after a change in social status to detect modifications mainly linked to variation in seminal liquid composition, and after a maturation cycle in the epididymis.
I will present the results of this experimental manipulation of social status.