title: Anopheles gambiae exploits the treehole ecosystem in western Kenya: a new urban malaria risk?
abstract: At six sites in western Kenya, we explored the presence of Anopheles immature stages in treeholes. An. gambiae larvae were found in 19 species, 13 of which are exotic. The most common exotic species were Delonix regia, Jacaranda mimosipholia, and Eucalyptus citrodora. In Kisumu city, longitudinal assessments of 10 Flamboyant trees showed repeated presence of An. gambiae s.s. in treeholes with water. Production of Anopheles larvae did not correlate with habitat volume but with habitat height, showing a strong but statistically insignificant negative correlation. During a dry season, eggs recovered by rinsing dry treeholes hatched into 2.5 +/- 3.06 An. gambiae and 7.9 +/- 8.2 Aedes larvae. In cage experiments, An. gambiae s.s. laid more eggs in water originating from treeholes than in distilled or lake water, implying preference for ovipositing in this habitat. Our findings indicate that treeholes represent a hitherto unrecognized habitat for malaria vectors, which needs further studies.
authors.affiliation: International Centre of Insect Physiology and Ecology, Kisii, Kenya. fomlin@icipe.org
authors.forename: Francois X
authors.initials: FX
authors.lastname: Omlin
authors.forename: John C
authors.initials: JC
authors.lastname: Carlson
authors.forename: C Brandon
authors.initials: CB
authors.lastname: Ogbunugafor
authors.forename: Ahmed
authors.initials: A
authors.lastname: Hassanali
mesh_terms: D000818:Animals; D000852:Anopheles / Q000254:growth & development* / Q000469:parasitology / Q000502:physiology; D017753:Ecosystem; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000254:growth & development* / Q000469:parasitology; D007630:Kenya; D008288:Malaria / Q000469:parasitology / Q000635:transmission*; D009032:Mosquito Control; D010058:Oviposition / Q000502:physiology; D011157:Population Dynamics; D014197:Trees; D014505:Urban Population; D014867:Water / Q000469:parasitology*
chemical_list: D014867:Water