Badge size reflects sperm oxidative status within social groups in the House Sparrow Passer domesticus
Alfonso Luis Rojas Mora, Magali Meniri, Gaëtan Glauser, Armelle Vallat & Fabrice Helfenstein
| Résumé |
The phenotype-linked fertility hypothesis proposes that male
ornaments reflect male fertility. Male ornaments could honestly
signal sperm quality due to the high susceptibility of sperm to
free radicals on the one hand and the negative impact of oxidative
stress on ornament elaboration on the other hand. Thus, only males
with superior antioxidant defenses could bear the cost of more
elaborated sexual ornaments without suffering adverse fitness
costs. Yet, in species where males experience differential access
to fertile females, a trade-off emerges between investing into
traits favoring mating opportunities (e.g., secondary sexual
ornaments, social dominance, mate-guarding behaviors, etc.) or into
traits favoring sperm competitive ability (e.g., sperm numbers and
quality). When male sexual ornaments promote greater access to
fertile females, a negative relationship can then be predicted
between ornamentation and sperm quality. We tested the latter
hypothesis and the phenotype-linked fertility hypothesis in wild
House Sparrows Passer domesticus by exploring the relationships
between sperm quality, melanin-based ornamentation, and redox
status in blood and sperm. We found no correlation between badge
size and sperm swimming performance. However, we found that within
a social group, large-badged males better protect their ejaculates
from oxidative stress, and thus produce less oxidized ejaculates.
Additionally, we found that badge size did not reflect social
dominance, and thus the protection of the ejaculate is independent
of males' ability to monopolize resources. Our results suggest that
badge size might reflect male investment into the antioxidant
protection of their sperm relative to a given social environment,
and thus females may accrue both direct and indirect benefits by
mating with large-badged males producing less oxidized
ejaculates. |
| Mots-clés |
Male ornament, secondary sexual character, melanin-based ornament, sperm quality, sperm velocity, oxidative stress, antioxidative defences |
| Citation | Luis Rojas Mora, A., Meniri, M., Glauser, G., Vallat, A., & Helfenstein, F. (2016). Badge size reflects sperm oxidative status within social groups in the House Sparrow Passer domesticus. Frontiers in Ecology and Evolution, 4, 67-76. |
| Type | Article de périodique (Anglais) |
| Date de publication | 1-6-2016 |
| Nom du périodique | Frontiers in Ecology and Evolution |
| Volume | 4 |
| Pages | 67-76 |
| Liée au projet | Oxidative stress in avian semen: causes and consequences ... |