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

RIBIgIRO, H. & RAMOS, H. Cunha -- <strong>Research</strong> on the mosquitoes o[ Angola -- X
content of the breeding water was determined in 10 biotopes, ranging
from 0.4 to 4.15 (mean 2.3) g/1 (NaCl). The FH of the breeding water,
measured in 10 biotopes, ranged from 5.4 to 8.0 (mean 6.6).
In 18 out of the 36 quinque/asciatus breeding places here concerned
no larvae of other mosquitoes were found, while in the remaining
half of the biotopes larvae of 13 Culex spp., 2 Anopheles spp. and 2
A edes spp. were recorded as associates. These were as follows, by
decreasing order of frequency: C. p. pipiens (in 7 instances, confirmed
by the terminalia of reared males), C. dttttoni and C. tigripes (4, each),
An. coustani, Ae. aegypti and C. simpsoni form A (2, each) and An.
listeri, Ae. natronitts, C. cinereus, C. kingiants, C. nebulosus, C. thalassius,
C. theileri, C. toroensis, C. tri/ilatus, C. tritaeniorhynchus and
C. univittatus (once). Differently from Luanda where, in 1971, the
invader A e. aegypti was, by far, the main associate of quinque/asciatus
(69), it seems that in stabilized situations this role is played by
pipiens s. sir. in the areas where both forms are sympatric, and by
duttoni and tigripes in other areas. Anyhow, the characteristic low percentage
of quinque/asciatus breeding places with other associated mosquito
larvae seems to be due to the ability of this form to breed in
waters with a high organic matter content of animal origin, not
suitable for other species. Under favorable conditions, larval associations
become relatively more frequent as other types of waters are
used by quinque/asciatus and, inversely, under stabilized situations of
heavy competition (e.g., as those following the invasion of a town by
A e. aegypti), its larval associations decrease with the confinement of
quinque/asciatus to its more characteristic breeding area of foul
waters.
Beyond the data already published on adult quinquefasciatus from
Lobito and Luanda (op. cit.), the following observations are based on
358 adults of this form caught throughout the country. From these,
115 were males while 243 were females, these ones being identified
as quinque/asciatus on the basis of the ratio of the length of the upper
fork-cell to its stem (see above). Only 2 males and 6 unfed females
were caught in the outside: the males and 2 of the females resting near
their breeding places and 4 females when biting man in the open, at
dusk. All the remaining 350 adults were caught in human habitation,
though many catches of other mosquito species were carried out in
cow-houses and pigsties. Te ratio of the number of males to that of
98 Estud., Ens. e Doc.- 134