The most important
vectors of human Plasmodium in the neotropics belong to the subgenus
Nyssorhynchus
.
These species are generally sympatric in terms of their geographical distributions.
Some are difficult to identify based solely on examination of adult females using
the available morphological keys, in these cases examination of immature stages
and male genitalia is required to make correct determinations. However, in epidemiological
studies it is necessary to identify the species of adult females which are found
near humans, i.e. in studies of malaria transmission or evaluation of control
measures. The purpose of the present study was to evaluate the discrimination
of adult females of different species of
Nyssorhynchus isolated mainly
from Southern Colombia (department of Putumayo), using morphometric analysis.
Adult females were obtained after rearing larvae collected in natural breeding
places and from the progeny of females collected on humans. The morphological
characteristics of the immature stages allowed the identification of four species
of the subgroup Oswaldoi from Southern Colombia:
Anopheles rangeli
Gabaldon, Cova Garcia & Lopez,
An. oswaldoi (Peryassu),
An. benarrochi
Gabaldon, Cova Garcia & Lopez and
An. triannulatus (Neiva & Pinto).
The species
An. nuneztovari (Gabaldon) from the Northwest of Colombia was
included for comparison. Morphometric analysis allowed differentiation of the
females of all species to a confidence level approaching 90% using principal components
analysis of 10 wing and leg variables, followed by canonical variate analysis
of the first four principal components. We conclude that morphometrics may represent
a useful taxonomic tool for this group and that its use should be further studied.
