In order to determine if habitat similarity is correlated
with a similarity of sensilla pattern, we analyzed six species of Triatominae
present in two biogeographic regions of Brazil: the "caatinga" and the
"cerrado". In broad terms
Triatoma infestans
(cerrado)
and T.
brasiliensis
(caatinga)
are found in human domiciles, T.
sordida
(cerrado) and T.
pseudomaculata
(caatinga) colonize peridomestic habitats, and
Rhodnius neglectus
(cerrado) and R.
nasutus
(caatinga)
inhabit palm tree crowns. The number and distribution of four sensilla types (bristles,
thin and thick walled trichoidea, and basiconica) were compared in these species.
Sexual dimorphism of sensilla patterns was noted in
T. sordida,
T. brasiliensis
and
T. pseudomaculata. A principal component analysis showed three main
groups: (i) species that live in the palms, (ii) domiciliated species and (iii)
those living in the peridomestic habitat.
T. infestans almost exclusively
domestic, was placed at the centre of the canonical map and some individuals of
other species overlapped there. These results support the idea that the patterns
of antennal sensilla are sensitive indicators of adaptive process in Triatominae.
We propose that those species that inhabit less stable habitats possess more types
of sensilla on the pedicel, and higher number of antennal sensilla.
