@article{PAR00002743,
  title = {{L}atitudinal distribution, migration, and testosterone levels in birds},
  author = {{G}aramszegi, {L}.{Z}. and {H}irschenhauser, {K}. and {B}okony, {V}. and {E}ens, {M}. and {H}urtrez {B}ouss{\`e}s, {S}ylvie and {M}oller, {A}.{P}. and {O}liveira, {R}.{F}. and {W}ingfield, {J}.{C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}ropical bird species usually have lower testosterone ({T}) levels during breeding than temperate species. {H}owever, the potential mechanisms behind the positive interspecific correlation between {T} and latitude remain unexplored. {I}n a comparative study of more than 100 bird species, we examined whether social constraints during male-male competition arising from migration and breeding synchrony are responsible for the latitude effects. {S}pecies that breed at higher latitudes are more likely to migrate and experience more intense intrasexual competition upon spring arrival than nonmigrant species from lower latitudes. {A}dditionally, species from higher latitudes cope with shorter breeding seasons and thus with more synchronous breeding, which selects for high {T} titers via increased male-male conflicts. {A}ccordingly, peak {T} levels were associated with migration and the duration of the egg laying period that reflects breeding synchrony. {B}ecause migration and breeding synchrony were related to latitudinal distribution, they appear to be important components of the latitude effects on {T}. {A} multivariate model controlling for covariation of predictor variables revealed that latitude remained the strongest predictor of peak {T}. {T}herefore, selection due to migration and breeding synchrony may partially cause the latitude effect, but other geographically varying factors may also play a role in mediating peak {T} levels at different latitudes.},
  keywords = {{A}ggression ; {A}ndrogens ; {E}volution ; {P}hylogeny ; {S}teroid hormones ; {T}erritorial conflicts},
  booktitle = {},
  journal = {{A}merican {N}aturalist},
  volume = {172},
  numero = {4},
  pages = {533--546},
  ISSN = {0003-0147},
  year = {2008},
  DOI = {10.1086/590955},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00002743},
}