@article{fdi:010058954,
  title = {{P}hysiological correlates of ecological divergence along an urbanization gradient : differential tolerance to ammonia among molecular forms of the malaria mosquito {A}nopheles gambiae},
  author = {{F}ossog, {B}. {T}. and {A}ntonio-{N}kondjio, {C}. and {K}engne, {P}ierre and {N}jiokou, {F}. and {B}esansky, {N}. {J}. and {C}ostantini, {C}arlo},
  editor = {},
  language = {{ENG}},
  abstract = {{B}ackground: {L}imitations in the ability of organisms to tolerate environmental stressors affect their fundamental ecological niche and constrain their distribution to specific habitats. {E}volution of tolerance, therefore, can engender ecological niche dynamics. {F}orest populations of the afro-tropical malaria mosquito {A}nopheles gambiae have been shown to adapt to historically unsuitable larval habitats polluted with decaying organic matter that are found in densely populated urban agglomerates of {C}ameroon. {T}his process has resulted in niche expansion from rural to urban environments that is associated with cryptic speciation and ecological divergence of two evolutionarily significant units within this taxon, the molecular forms {M} and {S}, among which reproductive isolation is significant but still incomplete. {H}abitat segregation between the two forms results in a mosaic distribution of clinally parapatric patches, with the {M} form predominating in the centre of urban agglomerates and the {S} form in the surrounding rural localities. {W}e hypothesized that development of tolerance to nitrogenous pollutants derived from the decomposition of organic matter, among which ammonia is the most toxic to aquatic organisms, may affect this pattern of distribution and process of niche expansion by the {M} form. {R}esults: {A}cute toxicity bioassays indicated that populations of the two molecular forms occurring at the extremes of an urbanization gradient in {Y}aounde, the capital of {C}ameroon, differed in their response to ammonia. {T}he regression lines best describing the dose-mortality profile differed in the scale of the explanatory variable (ammonia concentration log-transformed for the {S} form and linear for the {M} form), and in slope (steeper for the {S} form and shallower for the {M} form). {T}hese features reflected differences in the frequency distribution of individual tolerance thresholds in the two populations as assessed by probit analysis, with the {M} form exhibiting a greater mean and variance compared to the {S} form. {C}onclusions: {I}n agreement with expectations based on the pattern of habitat partitioning and exposure to ammonia in larval habitats in {Y}aounde, the {M} form showed greater tolerance to ammonia compared to the {S} form. {T}his trait may be part of the physiological machinery allowing forest populations of the {M} form to colonize polluted larval habitats, which is at the heart of its niche expansion in densely populated human settlements in {C}ameroon.},
  keywords = {{L}ocal adaptation ; {F}undamental ecological niche ; {E}nvironmental stressor ; {E}volution of tolerance ; {U}rbanization ; {M}alaria ; {M}osquito ; {CAMEROUN}},
  booktitle = {},
  journal = {{B}mc {E}cology},
  volume = {13},
  numero = {},
  pages = {1},
  ISSN = {1472-6785},
  year = {2013},
  DOI = {10.1186/1472-6785-13-1},
  URL = {https://www.documentation.ird.fr/hor/fdi:010058954},
}