The costs of mounting an immune response are reflected in the reproductive fitness of the mosquito, Anopheles gambiae
, Ahmed, A. M., Baggott, S.; Maingon, R. and Hurd, H. . 2002
We have used Anopheles gambiae, a major vector of malaria in Africa, to test the
hypothesis that the operation of a surveillance or immune system against microorganisms
and parasites can be costly to the reproductive success of the host. Blood-fed
mosquitoes were challenged with an immune elicitor, lipopolysaccharide (LPS), and
their resultant antimicrobial activity, accumulation of yolk protein in the ovary and
egg production was monitored. Humoral activity against the Gram-positive bacterium
Micrococcus luteus was induced by LPS injection in a dose-responsive manner.
LPS treatment also caused a concomitant significant reduction in the accumulation of
protein in ovaries 24 h after injection and in the production of eggs during the same
gonotrophic cycle. Unlike immune stimulation, reduction in reproductive fitness was
not dose responsive. Oral administration of LPS also significantly reduced ovarian
protein content although we could not detect the presence of anti-M. luteus activity
in the gut tissue by using an inhibition zone assay. These findings indicate that
immune stimulation imposed reproductive fitness costs on mosquitoes.
