Simulium (Psaroniocompsa) tergospinosum new species (Diptera: Simuliidae) in siolii group from the southern part of the State of Amazonas, Brazil

The larva, pupa, male and female of Simulium tergospinosum n. sp. are described and illustrated. The adults of this new species share many characters with species in the subgenus Psaroniocompsa, where it is placed. The larva of this species bears dorsal and lateral triangular tubercles on the abdomen and multiply branched scale-like setae on the body, suggesting that it belongs to the S. siolii species group. S. tergospinosum n.sp. was collected along the Juma River, Apuí county, in the southern part of the State of Amazonas, Brazil. The Juma, a black-water river, is a tributary of the Aripuanã River in the Madeira River hydrographic basin, on the southern part of Amazonas. Females were collected biting humans along the water courses during the sampling period (in the dry season).

Chromosomal comparisons among and within populations of Simulium (Chirostilbia) pertinax (Diptera, Simuliidae)

Chromosomal studies were carried on six larval populations of Simulium (Chirostilbia) pertinax from different locations in Brazil. Larvae were collected in the states of Paraná, Rio Grande do Sul, Rio de Janeiro and São Paulo. Polytene chromosome map comparisons within and among populations showed no differences in banding pattern, except for some limited polymorphism (secondary NOR and four band polymorphisms). There were no chromosomal variations associated with the resistance or susceptibility of the larvae to temephos. The chromosomal homosequentiality found among the six populations suggests that S. pertinax may be a monomorphic species.

Simuliid blackflies (Diptera: Simuliidae) and ceratopogonid midges (Diptera: Ceratopogonidae) as vectors of Mansonella ozzardi (Nematoda: Onchocercidae) in northern Argentina

Mansonella ozzardi, a relatively non pathogenic filarial parasite of man in Latin America, is transmitted by either ceratopogonid midges or simuliid blackflies. In the only known focus of the disease in north-western Argentina the vectors have never been incriminated. This study investigated the potential vectors of M. ozzardi in this area. The only anthropophilic species of these Diptera families biting man at the time of the investigation were Simulium exiguum, S. dinellii, Culicoides lahillei and C. paraensis. Using experimentally infected flies S. exiguum and both species of Culicoides allowed full development of microfilariae to the infective stage, with C. lahillei being a more competent host than S. exiguum. Based on these data, biting rates and natural infectivity rates it is probable that at the begininning of the wet season C. lahillei is the main vector of M. ozzardi and both C. paraensis and S. exiguum secondary vectors. Additionally, it was found that a single dose of ivermectin was ineffectual in eradicating M. ozzardi from infected individuals in this area.

Simulium cuasiexiguum, a new blackfly species (Diptera: Simuliidae) from the Minaçu area in the State of Goiás, Central Brazil

During studies of Simuliidae at a suspected new focus of human onchocerciasis in central Brazil a new species of Simulium was found. Full descriptions of the adults and pupae of this species, S. cuasiexiguum, are described here, its affinities to closely related species in the subgenus Notolepria are discussed and its distribution in Brazil recorded.

Stomach content analyses of Simulium perflavum Roubaud 1906 (Diptera: Simuliidae) larvae from streams in Central Amazônia, Brazil

Stomach contents of Simulium perflavum Roubaud larvae were analyzed and compared with plankton and periphyton collected in five streams, in Central Amazonia (Manaus and Presidente Figueiredo counties), in Sep./Oct.1996 (dry season) and Feb./Mar. 1997 (rainy season). A total of 1,400 last-instar larvae were dissected; the stomach contents were analyzed using different methods: fresh and after oxidation. A total of 87 taxa (algae, diatoms and rotifers) were found in the stomach contents. In each stream, qualitative samples of plankton and periphyton were collected; these were mounted between slides and cover slips. A total of 94 taxa of plankton and 54 taxa of periphyton were collected. One species of Rotifera was present in the stomach contents, plankton and periphyton. Cluster analysis based on species composition of the organisms present in the stomach contents grouped the streams into two major groups, each belonging to a different drainage area. Correlations based on presence/absence of species of microalgae in the stomach contents, plankton and periphyton indicated significant associations (p<0.05) between stomach contents and plankton and between plankton and periphyton (z test); the Sorensen coefficient and cluster analysis corroborate the same associations.

Morphometric comparison of Simulium perflavum larvae (Diptera: Simuliidae) in relation to season and gender in Central Amazônia, Brazil

Number of larval instars, age structure and environmental effects on these parameters represent basic information in the study of insect population biology. When species have economic importance, this information is essential in order to choose the best period to apply different control methods and to determine the stages of the life cycle of the insect that are most susceptible to each treatment. The family Simuliidae has many species of medical/veterinary importance in the world, and some studies in the temperate region have suggested that the number of larval instars and the larval size can vary according to the season, gender and some environmental factors, such as temperature and diet. This study, with the zoophilic species Simulium perflavum Roubaud, is the first in the Neotropics observing some of these factors and will serve as a template for other species of medical importance in the region. S. perflavum larvae were collected in five streams in Central Amazônia (Manaus and Presidente Figueiredo counties, State of Amazonas), in Sept./Oct. 1996 (dry season) and Feb./Mar. 1997 (rainy season). These larvae were measured (lateral length of head capsule and width of cephalic apodema) to determine the number of larval instars (n=3985), to compare the larval size between seasons and genders (last and penultimate larval instars, n=200). Seven larval instars were determined for this species using frequency distributions, t-tests and Crosby´s growth rule. Significant differences were not detected (t-test, p>0.05) in larval size between seasons and genders. Our results differ from some found in temperate regions suggesting that in the Neotropical region the larval size in different seasons and different genders remains constant, although some environmental parameters, such as diet, change depending on the season.

Black flies (Diptera: Simuliidae) of French Guiana: cytotaxonomy and a preliminary list of species

The objectives of the present study were to broaden the survey of simuliid species in French Guiana and to cytologically analyze the species in the Simulium perflavum species group. Twelve species of Simulium were collected from which S. goeldii, S. quadrifidum, S. trombetense, S. near incrustatum, S. metallicum (s.l.) sp1, S. metallicum (s.l.) sp2 and S. ochraceum (s.l.) are reported for the first time for this region. The only species collected in the S. perflavum group was S. rorotaense; 34 larvae of this species were cytologically analyzed, all of which had the standard sequence. S. metallicum (s.l.), S. ochraceum (s.l.), S. guianense (s.l.) and S. oyapockense (s.l.) are involved with transmission of onchocerciasis in Central and South America, however, in French Guiana these species were not found biting humans during the sampling period. With the few collections made during this study, we increase the number of simulid species known in French Guiana from 6 to 13. It is clear that more simuliid species can be expected to be found when more sampling is done, including collections in other ecoregions in French Guiana.

Identification of entomopathogenic Bacillus isolated from Simulium (Diptera, Simuliidae) larvae and adults

Entomopathogenic bacteria isolated from Simulium larvae and adults from breeding sites in the states of São Paulo and Rio de Janeiro, Brazil, were identified as 18 strains of Bacillus thuringiensis and one of B. sphaericus. Most of these strains were serotyped according to their flagellar antigens. However, nine of the B. thuringiensis samples, could not be serotyped and were designated as "autoagglutinating"; they were also shown to be toxic in preliminary tests against Aedes aegypti larvae. Additionally, B. sphaericus was also shown to be toxic towards Culex quinquefasciatus larvae.

A Cladistic Analysis of Inaequalium (Coscarón & Wygodzinsky, 1984), with Information on Geographical Distribution (Diptera: Simuliidae)

The black flies of the genus Inaequalium present a Neotropical distribution, with Panama at the northern limit, and the Argentinian pampas at the southern, but do not occur in the Central Amazon. This study offers a cladistic analysis establishing a hypothesis of relationships between the species of Inaequalium. A total of 37 characters have been considered in order to establish the hypothetic phylogenetic relationships. Cerqueirellum (Py-Daniel, 1983) was considered as outgroup. Data were analyzed using Henning 86 version 1.5. Wich the ie* command and implicit enumeration a unique possible cladogram was obtained in Inaequalium with 52 steps, and a CI of 0.76 and RI of 0.81. Two well-defined clades was obtained in the resulting cladogram, the "botulibranchium" species-group, includes I. travassosi, I. souzalopesi, I. botulibranchium and I. petropoliense, and the "inaequale" species-group, includes I. rappae, I. nahimi, I. inaequale, I. leopoldense, I. subnigrum, I. diversibranchium, I. mariavulcanoae, I. nogueirai, I. beaupertuyi, I. clavibranchium and I. subclavibranchium.

Araucnephia iberaensis n. sp., a Neotropical Black Fly with a Peculiar Distribution (Diptera-Simuliidae)

Araucnephia Wygodzinsky & Coscarón is a Neotropical black fly genus in which only one species from Central Chile is known. Another species has now been found in Corrientes province on the eastern side of the Iberá tropical swamps of Argentina, on the western border of the mountainous region of southern Brazil. This new species, A. iberaensis, is herein described and illustrated and information on its bionomics is recorded. It is an interesting species because previous to its discovery no black fly genus or subgenus from Central Chile region has been found in tropical areas, because these two regions are separated by the Monte and Pampas realms. Similarly, no Brazilian genus or subgenus has crossed the Andes mountains to Chile. A comparison with other Neotropical, Nearctic, Ethiopian (Afrotropical) and Australian Prosimuliini (sensu Crosskey & Howard) showed Araucnephia to be a valid taxon most closely related to Araucnephioides (sympatric in Chile). Araucnephia also shows great affinities with Lutzsimulium from Southeast Brazil and Argentina and Paracnephia from South Africa.

Trichomycete Fungi (Zygomycota) Associated with the Digestive Tract of Simulium goeldii Cerqueira & Nunes de Mello and Simulium ulyssesi (Py-Daniel & Coscarón) (Diptera: Simuliidae) Larvae, in Central Amazônia, Brazil

Trichomycete fungi are associated with digestive tract of black fly larvae. These fungi have not been studied in Brazil, knowing them and their relationship with black flies could be an alternative to control vector populations. The objectives of this study were to survey the Trichomycete fungi associated with larvae of Simulium goeldii and S. ulyssesi, and to determine if there is specificity and/or difference in the infection rates in these species. Black flies were collected in Central Amazônia, Brazil. Three genera of Trichomycetes were found: Harpella, Genistellospora and Smittium. All these fungi were common to both black fly species.

Description of Simulium damascenoi (Diptera: Simuliidae) male and the black-fly species from the State of Amapá, Brazil

Five species are included in the Simulium siolii group, which is placed in the subgenus Psaroniocompsa (Diptera: Simuliidae). Of these five species, only two (Simulium siolii Py-Daniel and Simulium tergospinosum Hamada) have been described in all their life stages, except eggs. Knowledge of the taxonomic characters of all life stages of a species is important in order to clarify interspecific and higher-level taxonomic relationships. The objectives of the present study are to describe the male of Simulium damascenoi Py-Daniel, to provide a list of black-fly species their bionomics and distributions in the state of Amapá, Brazil, and to provide an identification key for larvae and pupae for these species.

Larval biometry of Simulium rubrithorax (Diptera: Simuliidae) and size comparison between populations in the states of Minas Gerais and Roraima, Brazil

The number of larval instars of Simulium (Hemicnetha) rubrithorax Lutz (Diptera: Nematocera) was determined using the lateral length of the head capsule. In this study 1,035 larvae, of different sizes, were measured (639 from the state of Roraima and 396 from the state of Minas Gerais). A frequency distribution analysis was carried out on the measurements of the lateral length of the head capsule to determine the number of larval instars. The limits of each instar were defined by the lower frequency of the measurements falling in a range of values, by the presence of the "egg burster" that characterizes the first larval instar, and by the developmental stage of the gill histoblast. The determination of the instar number was tested using a Student's t-test (p < 0.05), the Dyar rule and the Crosby growth rule. The results indicate the existence of 7 larval instars for this species, although this result was not in accordance to the Crosby rule. Last-instar larvae from two widely separated geographical populations (Roraima and Minas Gerais), collected in habitats with different water temperature were compared and no differences (p > 0.05) were observed between them.

Evaluation of the impact of Bacillus thuringiensis serovar israelensis and Temephos, used for the control of Simulium (Chirostilbia) pertinax Kollar, 1832 (Diptera, Simuliidae) on the associated entomofauna, Paraty, state of Rio de Janeiro, Brazil

The study was set up to evaluate the impact of two commercial larvicide formulations, Bacillus thuringiensis serovar israelensis base (Bti) at 15 ppm/1 min and temephos at 0.03 ppm of active ingredient, used to control Simulium pertinax populations, on associated non-target entomofauna occupying the same breeding sites. The experiments were carried out on the Pedra Branca and Muricana rivers, on the slopes of Serra do Mar massif, municipality of Paraty, state of Rio de Janeiro, Brazil. Bti was applied to the river Pedra Branca and temephosto theriver Muricana. On both rivers, treatment and control sections were labeled as such, each one with two observation posts: slow moving water and fast water regions respectively. Artificial substrata was used to evaluate the abundance of associated entomofauna. Attached immature stages of arthropods were removed from both of its surfaces fortnightly. Were collected, from the two rivers, 28 477 specimens of the entomofauna associated with S. pertinax. The families Hydropsychidae, Chironomidae, Bactidae, Simuliidae, Blephariceridae and Megapodagrionidae were represented. These was an impact of temephos on the entomofauna associated with S. pertinax only in Simuliidae and Chironomidae, and to Bti only in Simuliidae. However, the reduction in their numbers was not statistically significant.

Simulium lobatoi, new species of blackfly (Diptera: Simuliidae) from the states of Mato Grosso and Goiás, Central Brazil

During studies on the taxonomy of the Simuliidae of Brazil, a new species of Simulium was found. Full descriptions of the adults and pupae of this species are described here, its affinities with other species are discussed and its distribution, biology, and medical importance in Brazil are recorded.