Research on the mosquitoes of Angola - Systematic Catalog of ...

RIBIglRO, H. & RAMOS, H. Cunha -- <strong>Research</strong> o the mosquitoes o[ Agola -- X
water biotopes, while 8 (5.3 per cent) were artificial containers, and 6 (4
per cent) were rock-pools. Ground water biotopes consisted of margins of
rivers and streams (38), ground pools from rains or floods (35), ponds
(16), earth drains (15), shallow earth-wells and water holes (13), pools
in river beds (13), borrow-pits (4), and coastal salt-water pools (2). As
artificial containers, were recorded cement tanks (3), barrels with water
for domestic uses (2), old rubber tyres (2) and the bottom of a boat.
The breending conditions of C. univittatus in all these sites were quite
varied, as it was to be expected of a mosquito occurring from the semidesert
in the South-western Angola to the gallery forest in the North of
the country. The breeding water was either limpid or turbid, high organic
matter contents being presumed in 34 of the biotopes. Exposition to sun
light and accompanying aquatic vegetation were also extremely variable.
Temperatures of 31øC were recorded in semiarid country. The chloridecontent
of the breeding water was usually quite low, though in a few
instances sal-water breeding was recorded, including what was thought
to be a sea-water ground pool (salinity not measured). In the 35 biotopes
in which the salt content was determined a mean of 1.I g/1 (NaCl)
was found, with a range 0.1-15.8. The pH of the water, examined in
74 larval biotopes, ranged from 4.9 to 8.0 (mean 6.0). The marked preference
of C. univitlatus for acid waters was put into evidence, as this was
the case in 63 of the breeding places examined (85 per cent), while the
water was neutral in 9 of them and had pHs of 7.5 and 8.0 in the
other two.
In 10 out of the 150 univittatus breeding places no associated mosquitoes
were found. As to the remainder 140 biotopes, larvae of other
species of Culex were present in 103 of them, while Anopheles spp.
occurred in 84 and A edes spp. were present only in 6. On the whole, 56
species of mosquitoes were found in association with C. univittatus in
its breeding sites: 24 species of Culex, 23 Anopheles, 4 Ficalbia, 3 Aedes,
1 A edeomyia and 1 Uranotaenia. The species most often recorded as
associates of larval univittatus were, by decreasing order of frequency:
Anopheles gambiae (29 times), Culex tigripes (28), An. squamosus (24),
C. antennatus (23), C. poicilipes (22), An. coustani s.s. and C. simpsoni
form A (15 times each), An. pharoensis and C. annulioris (13 times each),
An. listeri (12), C. p. pipiens (11), An. pretoriensis and An. ziemanni (9
each), An. rhodesiensis and An. rufipes (7 each), An. [unestus s.s. and
C. duttoni (6 each), Aedeomyia furlurea and Ficalbia mimomyiaformis
120 Estud., Etzs. e Doc.- 134