Biological cost of tolerance to heavy metals in the mosquito Anopheles gambiae
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Date
2011-06-01
Authors
Hassanali, Ahmed
Mireji, P. O.
Keating, J.
Mbogo, C. M.
Muturi, M. N.
Githure, J.I.
Beier, J.C.
Journal Title
Journal ISSN
Volume Title
Publisher
Med Vet Entomol
Abstract
The global rate of heavy metal pollution is rapidly increasing in different habitats. Anopheles
malaria vector species appear to tolerate many aquatic habitats with metal pollutants, despite their
normal proclivity for ‘clean’ water (i.e., generally water free of organic matter). Investigations
were conducted to establish whether there are biological costs for tolerance to heavy metals in
Anopheles gambiae Giles sensu stricto (Diptera: Culicidae), and to assess the potential impact of
heavy metal pollution on mosquito ecology. Anopheles gambiae s.s. were selected for cadmium,
copper or lead tolerance through chronic exposure of immature stages to solutions of the metals
for three successive generations. Biological costs were assessed in the fourth generation by
horizontal life table analysis. Tolerance in larvae to cadmium (as cadmium chloride, CdCl2),
copper (as copper II nitrate hydrate, (Cu (NO3)2. 2·5H2O) and lead (as lead II nitrate, (Pb (NO3)2),
monitored by changes in LC50 concentrations of the metals, changed from, 6.07, 12.42 and 493.32
μg/L to 4.45, 25.02 and 516.69 μg/L, respectively, after 3 generations of exposure. The metalselected
strains had a significantly lower magnitude of egg viability, larval and pupal survivorship,
adult emergence, fecundity and net reproductive rate than the control strain. The population
doubling times were significantly longer and the instantaneous birth rates lower in most metalselected
strains relative to the control strain. Our results suggest that although An. gambiae s.s.
displays the potential to develop tolerance to heavy metals, particularly copper, this may occur at a
significant biological cost, which can adversely affect its ecological fitness.
Description
doi:10.1111/j.1365-2915.2010.00863.x.
Keywords
Anopheles gambiae, biological cost, cadmium, copper, heavy metals, lead, tolerance
Citation
Med Vet Entomol. 2010 June ; 24(2): 101–107. doi:10.1111/j.1365-2915.2010.00863.x.