Origin and phylogeography of the Chagas disease main vector Triatoma infestans based on nuclear rDNA sequences and genome size.

For about half of all Chagas disease cases T. infestans has been the responsible vector. Contributing to its genetic knowledge will increase our understanding of the capacity of geographic expansion and domiciliation of triatomines. Populations of all infestans subcomplex species, T. infestans, T. delpontei, T. platensis and T. melanosoma and the so-called T. infestans "dark morph", from many South American countries were studied. A total of 10 and 7 different ITS-2 and ITS-1 haplotypes, respectively, were found. The total intraspecific ITS-2 nucleotide variability detected in T. infestans is the highest hitherto known in triatomines. ITS-1 minisatellites, detected for the first time in triatomines, proved to be homologous and thus become useful markers. Calculations show that ITS-1 evolves 1.12-2.60 times faster than ITS-2. Despite all species analyzed presenting the same n=22 chromosome number, a large variation of the haploid DNA content was found, including a strikingly high DNA content difference between Andean and non-Andean specimens of T. infestans (mean reduction of 30%, with a maximum of up to 40%) and a correlation between presence/absence of minisatellites and larger/smaller genome size. Population genetics analysis of the eight composite haplotypes of T. infestans and net differences corroborate that there are clear differences between western and eastern populations (60%), and little genetic variation among populations (1.3%) and within populations (40%) within these two groups with migration rates larger than one individual per generation corresponding only to pairs of populations one from each of these groups. These values are indicative either of a large enough gene flow to prevent population differentiation by drift within each geographic area or a very recent spread, the latter hypothesis fitting available data better. Phylogenetic trees support a common ancestor for T. infestans and T. platensis, an origin of T. infestans in Bolivian highlands and two different dispersal lines, one throughout Andean regions of Bolivia and Peru and another in non-Andean lowlands of Chile, Paraguay, Argentina, Uruguay and Brazil.

Comparative ultrastructural analysis of the antennae of Triatoma guazu and Triatoma jurbergi (Hemiptera: Reduviidae) during the nymphal stage development.

The specific concept of two triatominae species of epidemiological importance in the Mato Grosso Region (Brasil), Triatoma guazu Lent & Wygodzinsky, 1979 and Triatoma jurbergi Carcavallo, Galvão & Lent, 1998, the antenniferous tubercle and the four antennal segments of nymphs from the first to fifth instar were morphologically compared by scanning electron microscopy. The main differences observed were that the antenniferous tubercle in T. guazu did not present a smaller tubercle in the base of the larger tubercle. The first antennal segment in the fifth instar had sensilla distributed with an alternating array and the trichobothria in the first instar had half of its length reaching the third antennal segment. However, in T. jurbergi the antenniferous tubercle had two smaller tubercles in the base of the two larger tubercles. The first antennal segment in the fifth instar presents sensilla distributed in pairs, and the trichobothria in the first instar has only a small portion of the structure reaching the third antennal segment. These structures differentiated the nymphs of T. guazu and T. jurbergi.

Nuclear rDNA ITS-2 sequences reveal polyphyly of Panstrongylus species (Hemiptera: Reduviidae: Triatominae), vectors of Trypanosoma cruzi.

Panstrongylus species are widely distributed throughout the Americas, where they act as vectors of Trypanosoma cruzi, agent of Chagas disease. Their intraspecific relationships, taxonomic position and phylogeny in relation to other Triatomini were explored using ribosomal DNA (rDNA) internal transcribed spacer 2 (ITS-2) sequence polymorphisms and maximum parsimony, distance and maximum likelihood analyses of 10 populations representing six species of the genus (P. megistus, P. geniculatus, P. rufotuberculatus, P. lignarius, P. herreri and P. chinai). At the subspecific level, P. megistus appeared more homogeneous than P. rufotuberculatus and P. geniculatus (both with broader distribution). Several dinucleotide microsatellites were detected in the sequences of given species. Many of these microsatellites (GC, TA, GT and AT) showed different number of repeats in different populations and thus, may be very useful for population differentiation and dynamics analyses in future studies. The sequences of P. lignarius (considered sylvatic) and P. herreri (a major disease vector in Peru) were identical, suggesting that these species should be synonymised. Intrageneric analysis showed a clear separation of P. rufotuberculatus, with closest relationships between P. geniculatus and P. chinai, and P. megistus occupying a separate branch. Genetic distances between Panstrongylus species (0.11585-0.22131) were higher than those between Panstrongylus and other Triatomini (16 species from central and North America and South America) (0.08617-0.11039). The distance between P. megistus and P. lignarius/herreri (0.22131) was the largest so far recorded in the tribe. The pronounced differences in length and nucleotide composition suggest a relatively old divergence of Panstrongylus species. P. rufotuberculatus was closer to Mesoamerican Triatoma, Meccus and Dipetalogaster species than to other Panstrongylus. All Panstrongylus clustered with the Mesoamerican clade; P. rufotuberculatus clustered with the phyllosoma complex and T. dimidiata, with D. maxima and T. barberi in a basal position. The rest of Panstrongylus appeared paraphyletically in the tree. This is evidence suggesting polyphyly within the genus Panstrongylus, whose species may be related to the ancestors giving rise to central and North American Triatomini.

[Influence of temperature and humidity on the nymphal development of Rhodnius robustus]. / Influência da temperatura e umidade no desenvolvimento ninfal de Rhodnius robustus.

OBJECTIVE: To assess the significant differences in the nymphal development of the Rhodnius robustus Larrousse, 1927 under different temperatures and humidity conditions. This is a species found in the northern region of Brazil (states of Acre, Amazonas, and Pará), Colombia, Equator, Peru and Venezuela. METHODS: Three groups of triatominae were kept under the following laboratory conditions: 33/40 (33+1 degree C and 40+/-5% of relative humidity - RH), 33/70 (33+/-1 degree C and 70+/-5% RH), and 28/70 (28+/-1 degree C and 70+/-5% RH). The incubation period of the eggs, developmental time of each stage, mortality percentage, number of bloodmeals, and the total amount of time from the egg hatching to adult ecdysis were observed. RESULTS: The shortest average time of nymphal development was observed in the 28/70 group, with following averages: 14.4, 17.3, 20.3, 22.8, and 40. Significant differences were observed in the embryonic development between the groups (p<0.01). For all groups, the number of bloodmeals had a gradual increase near the adult phase, except for the 3rd instar of the 33/70 group. The smallest mortality percentages were seen in the 28/70 group. CONCLUSIONS: High temperatures, regardless of the humidity, can accelerate the biological development cycle of R. robustus. However, these temperatures can impair the colonies' survival, preventing their maintenance in the laboratory.

[Influence of the temperature and humidity on the biology of Rhodnius neglectus Lent, 1954, in laboratory conditions (Hemiptera, Reduviidae, Triatominae)]. / Influência da temperatura e umidade na biologia de Rhodnius neglectus Lent, 1954 em laboratório (Hemiptera, Reduviidae,Triatominae).

The objective of the present paper was to study the development of R. neglectus in the laboratory under different conditions of temperature and humidity. Three groups were prepared: 33/40 (33+/- 1 degree C and 40% +/-5% UR), 33/70 (33+/- 1 degree C and 70% +/-5% UR), and 28/70 (28+/- 1 degree C and 70% +/-5% UR). All these groups were observed daily to evaluate the eggs' incubation period, the development period of each instar nymph, the mortality rate of each stage, the frequency of feeding and the hatching - adult ecdysis period. The embryonic development showed significant differences between the treatment given, the group 33/40 presented the lowest incubation period. The lowest bloodmeals number was observed in the group 33/40 except for the first instar (group 28/70). The period of nymphal development was significantly reduced in the group 33/40, however, the mortality was high and the specimens did not reach the adult phase.

Influência da temperatura e umidade na biologia de Rhodnius neglectus Lent, 1954 em laboratório (Hemiptera, Reduviidae,Triatominae) / Influence of the temperature and humidity on the biology of Rhodnius neglectus Lent, 1954, in laboratory conditions (Hemiptera, Reduviidae, Triatominae)

O objetivo do presente trabalho foi observar o desenvolvimento de R. neglectus em diferentes condições de temperatura e umidade. Três grupos foram formados:33/40 (33+/- 1ºC e 40% +/-5% UR), 33/70 (33+/- 1ºC e 70% +/-5% UR), e 28/70 (28+/- 1ºC e 70% +/-5% UR). Todos os grupos foram observados diariamente para avaliação do período de incubação dos ovos, período de desenvolvimento dos estádios ninfais, percentual de mortalidade por estádio, número de repastos realizados, e período de desenvolvimento da eclosão a muda imaginal. O desenvolvimento embrionário apresentou diferenças significativas em todos os tratamentos, o grupo 33/40 apresentou o menor período de incubação. O menor número de repastos foi observado no grupo 33/40 exceto para o primeiro estádio (grupo 28/70). O período de desenvolvimento ninfal foi significativamente reduzido no grupo 33/40; entretanto, o percentual de mortalidade deste grupo foi alto, e os insetos não conseguiram realizar a muda imaginal.

The objective of the present paper was to study the development of R. neglectus in the laboratory under different conditions of temperature and humidity. Three groups were prepared: 33/40 (33+/- 1 degree C and 40% +/-5% UR), 33/70 (33+/- 1 degree C and 70% +/-5% UR), and 28/70 (28+/- 1 degree C and 70% +/-5% UR). All these groups were observed daily to evaluate the eggs' incubation period, the development period of each instar nymph, the mortality rate of each stage, the frequency of feeding and the hatching - adult ecdysis period. The embryonic development showed significant differences between the treatment given, the group 33/40 presented the lowest incubation period. The lowest bloodmeals number was observed in the group 33/40 except for the first instar (group 28/70). The period of nymphal development was significantly reduced in the group 33/40, however, the mortality was high and the specimens did not reach the adult phase.

[A new species of the oliveirai complex (new designation for matogrossensis complex) from the State of Rio Grande do Sul, Brazil]. / Nova espécie do complexo oliveirai (nova denominação para o complexo matogrossensis) (Hemiptera, Reduviidae, Triatominae) do estado do Rio Grande do Sul, Brasil.

The authors describe a new species of Triatominae (Hemiptera, Reduviidae) from the State of Rio Grande do Sul, Brazil. The study was made with specimens captured in basaltic formations, at an average altitude of 750 m.o.s.l. The new species is included in the oliveirai complex together with other four species T. williami, T. matogrossensis, T. guazu and T. jurbergi). The new species was compared with the most similar one, T. oliveirai, from which the main differences are on the proportions of head, ante and postocular regions, the general color pattern and the male genitalia, specially on the median process of the pygophore, the support of phallosome, the vesica and the process of the endosome.

[New geographical distribution of Triatoma deaneorum Galvão, Souza & Lima 1967, new designation for Triatoma deanei (Hemiptera, Reduviidae)]. / Ampliação da distribuição geográfica de Triatoma deaneorum Galvão, Souza & Lima 1967, nova denominação para Triatoma deanei (Hemiptera, Reduviidae).

Authors extend the geographical distribution of Triatoma deaneorum Galvão, Souza & Lima, 1967, new designation for Triatoma deanei, based on a specimen recently found in Chapada dos Guimarães, near to Cuiabá, Mato Grosso, Brazil. The new designation is based on the International Code of Zoological Nomenclature.

Presence of Panstrongylus rufotuberculatus (Champion, 1899) (Hemiptera: Reduviidae: Triatominae) in Argentina.

Panstrongylus rufotuberculatus is reported for the first time in Argentina. Four adults were attracted by the light of human dwellings in Calilegua National Park, Jujuy, at 1150 masl within the subtropical humid forest. The individuals were similar to those described in the literature. The epidemiological significance of this species is very low in the area, although deforestation might increase its role in the transmission of Trypanosoma cruzi.

[Geographical distribution and alti-latitudinal dispersion of some genera and species of the tribe Triatomini Jeannel, 1919 (Hemiptera, Reduviidae, Triatominae)]. / Distribuição geográfica e dispersão alti-latitudinal de alguns gêneros e espécies da tribo Triatomini Jeannel, 1919 (Hemiptera, Reduviidae, Triatominae).

With the currently known distribution of genera and species of the tribe Triatomini Jeannel, 1919, maps and diagrams were prepared, showing the geographical area occupied by the species and their respective dispersion in grades of latitude and altitude. Two genera are not treated: Panstrongylus Berg, 1879, already published and Triatoma Laporte, 1832, that is being published partially in several articles. Genus Eratyrus Stal, 1859, has two species, while Dipetalogaster Usinger, 1939, Mepraia Mazza, Gajardo & Joerg, 1940, Paratriatoma Barber, 1938 and recently created genus Hermanlentia Jurberg & Galvão, 1997, have only one each. The study of these maps and diagrams permits a better knowledge about some ecological requirements of Chagas' disease vectors and detects gaps in the geographical distribution, where the species were not found but probably they could be prevalent.

[Triatoma jurbergi sp. n. from the State of Mato Grosso, Brazil (Hemiptera, Reduviidae, Triatominae) with an updated list of synonyms and other taxa]. / Triatoma jurbergi sp. n. do norte do estado do Mato Grosso, Brasil (Hemiptera, Reduviidae, Triatominae) com uma atualização das sinonímias e outros Táxons.

Triatoma jurbergi n. sp. is described based on nine specimens of both sexes deposited in the Rodolfo Carcavallo Collection in the Oswaldo Cruz Institute Entomological Collection. The new species can be separated from the closely related Triatoma guazu Lent & Wygodzinsky, 1979 by several characters. The most important are longer anteocular region; thin and pointed juga: the shape of the eyes without concavity in the posterior edge; much longer second rostral segment, passing the posterior edge of eye; the absence of a ventral longitudinal depression on the abdomen; the general color redish, brown and orange and the male genitalia, mainly in the vesical lightly chitinized and smaller, the phallosome with apical projection and the pointed apex of the endosome process.

Atlas of Chagas disease vectors in the Americas

Habitats of Triatominae bugs are important from an epidemiological point of view. Each species is related to certain environmental conditions, and its significance as a vector for Trypanosoma cruzi is often linked to its proximity to human dwellings or the infestation of houses, corrals, pigeon or chicken coops, woodpiles, and/or other peridomiciliary sites. The authors of this chapter have agreed to provide a general list of references, mostly devoted either to those publications compiling the scattered bibliography or to some specific papers where a single species was studied, giving compiled bibliography added to the original research. Despite this bibliographical condensation, the list is long enough to provide a general idea about some basic references to each species

Atlas of Chagas disease vectors in the Americas

Authors have studied most of the known species of Triatominae with Scanning Electron Microscopy (SEM) JEOL and HITACHI S-500. They were able to photograph structures in these bugs belonging to the 5 known tribes. 12 of the 14 genera existing on the American Continent and Caribbean Islands, and 98 of the 111 recognized species of the subfamily. It was not possible to study either Bolbodera or Parabelminus with SEM

[External morphology of Triatoma rickmani Zeledón & Ponce, 1972 seen under scanning electron microscopy]. / Morfologia externa de Triatoma ryckmani Zeledón & Ponce, 1972 vista através da microscopia electrônica de varredura.

A male of Triatoma ryckmani Zeledón & Ponce, 1972, was studied by scanning electron microscopy. Only few specimens of this species are known. In this paper, some structures from the head, thorax, abdomen and distal region of the second leg are shown. Some of them could have taxonomic importance, as the oculo-ocellar region, the buccula, the anterolateral angle of the collar, the scutellum with the process longer than the main body, the stridulatory sulcus with an unusual backward vermiform area, and the tibia-tarsal articulation, with a spongy fossula. The last structure was absent in specimens previously studied (Lent & Wygodzinsky 1979). Differences between this specimen and others previously described by several authors are discussed.

[Alberprosenia malheiroi Serra, Atzingen & Serra, 1987 (Hemiptera, Reduviidae). Redescription and bionomics]. / Alberprosenia malheiroi Serra, Atzingen & Serra, 1987 (Hemiptera, Reduviidae). Redescrição e bionomia.

Alberprosenia malheiroi n. sp. first became known through an informal publication of a paper submitted a Congress, in 1980. The same diagnosis with a photograph was published in 1987, but no formal description has yet been made. The present authors describe adults and immature instars, establish a sintypical series and introduce bionomic data and data on the rearing of this species in insectary. The most evident differences between A. malheiroi n. sp. and A. goyovargasi, the former generic species, are the general colour pattern which is completely black; the interocular area, wider than an eye in dorsal view; the acute apex in collar tubercules and the significantly larger size, almost double that of the latter specie. The eggs are small attach themselves to the substratum in groups of either 3 or 4, are elipsoid with no lateral flattening, having a convex and prominent operculum, without conspicuous structures. Nymphs have the typical tribal and generic characteristics in each stage, the anteocular region being shorter than the postocular one. Pilosity appears in the second instar and becomes more evident with instar development. A. malheiroi n. sp. was captured in a forest, in wild (palm-tree) ecotopes associated with bats or birds, in the State of Para, Brazil. Trypanosoma cruzi was not found in any specimens. These triatomines were reared in +/- 25 degrees C and +/- 60% RH, the insects are quick and fly without difficulty. They fed well on pigeons and bats but not on rats, mice or hamsters. The eggs incubation period was thirteen days on average, and the evolution time of the nymphal period was a hundred and thirty two days on average.