Biodiversity and times of activity of mosquitoes (Diptera: Culicidae) in the biome of the Atlantic Forest in the State of Rio de Janeiro, Brazil.

A temporal observational study on culicid entomofauna was conducted in a region characterized as a fragment of the Atlantic Forest that forms the Tinguá Biological Reserve in the State of Rio de Janeiro. This investigation was performed with the aim of analyzing the influence of climatic factors (temperature and relative air humidity) on the activity levels at different times of the day among mosquito species within the ecosystems that form the Tinguá Biological Reserve. The abundance index and dominance coefficient were calculated in relation to 61 mosquito species that were caught at four sampling sites, in the mornings, afternoons, and evenings. The results revealed that culicid species were distributed with greater incidence during the two diurnal periods and that their preference for times of the day was directly influenced by the climatic variables analyzed. The latter acted as limiting factors for occurrences of mosquito species.

Disruption of Chrysomya megacephala growth caused by lignan grandisin.

The toxicity of tetrahydrofuran lignan grandisin was evaluated against larvae of Chrysomya megacephala F. (Diptera: Calliphoridae). The bioassay involved topical treatment on larvae, topical treatment on egg masses, and incorporation in the larval diet. Grandisin showed inhibition of postembryonic development by ovicidal (30%) and larvicidal (38%) effects and reduced larval weight (4 mg), when topically applied on egg masses and starving larvae (L1) at a concentration of 100 microg/microl. These findings elucidated the effect of grandisin on the C. megacephala life cycle and its potential to control C. megacephala populations.

Identification of fly eggs using scanning electron microscopy for forensic investigations.

Forensic entomology is the science that studies the role of insects in decomposing corpses and one of the most common uses is to estimate the post-mortem interval (PMI) based on insect activity on a decomposing body. Usually, flies are the first insects to reach a carcass and are able to oviposit on carrion within a few hours after death. Scanning electron microscopy (SEM) gives detailed information about morphological characters helping to identify the immature forms of flies and consequently serves as a tool in crime scene investigations. Sometimes, only eggs and larvae are found in corpses. Some dipteral species are important because their larvae develop in organic matter. The aim of this study is to identify eggs of species of forensic importance, such as Chrysomya megacephala, Chrysomya putoria, Lucilia cuprina, Lucilia eximia and Ophyra aenescens, using scanning electron microscopy (SEM). C. megacephala had no anastomosis or holes at the top of the islands and C. putoria had few anastomoses and no holes, whereas L. eximia and O. aenescens were found to have anastomoses and holes and L. cuprina had only anastomoses. The median area was bifurcated anteriorly in C. megacephala, L. eximia and O. aenescens and rounded in C. putoria and L. cuprina. Also the sculptures observed in the chorionic cells, the length and the way that median area ends up posteriorly are characteristics of great diagnostic value to identify muscoids of forensic importance.

[Mosquito (Diptera, Culicidae) ecology in the Iguaçu National Park, Brazil: 1 Habitat distribution]. / Ecologia de mosquitos (Diptera, Culicidae) em áreas do Parque Nacional do Iguaçu, Brasil: 1 Distribuição por hábitat.

A study of the mosquito fauna in the Iguaçu National Park focused on population behavior in four biotopes with different types of plant cover inside the Park. Systematic bimonthly diurnal and nocturnal human bait and Shannon trap captures were conducted in both forest and domiciliary environments over the course of 24 months. A total of 20,273 adult mosquito specimens belonging to 44 species were collected: Ochlerotatus serratus (10.3%), Haemagogus leucocelaenus (9.7%), Mansonia titillans (9.6%), and Chagasia fajardoi (8.8%) were the most frequently captured mosquitoes. Anopheles cruzii, Runchomyia theobaldi, Wyeomyia aporonoma, and Wy. confusa were captured almost exclusively in well-preserved areas with dense forest cover. Culex nigripalpus, Oc. pennai, Oc. serratus, Sabethes purpureus, and Sa. albiprivus were captured in three essentially sylvatic biotopes. Species captured in the forest areas around a dam were: An. albitarsis s.l., An. galvaoi, An. evansae, An. fluminensis, Coquillettidia venezuelensis, Cq. juxtamansonia, Wy. quasilongirostris, and Onirion personatum, Ch. fajardoi, Cq. fasciolata, Cq nitens, and Ma. titillans were the most frequently captured species in a residential area.

Ecology of Anopheline (Diptera, Culicidae), malaria vectors around the Serra da Mesa Reservoir, State of Goiás, Brazil. 1--Frequency and climatic factors.

The ecology of anopheline species (Diptera, Culicidae) was studied in the vicinity of the Serra da Mesa Reservoir, State of Goiás, Brazil. Climatic factors and frequency of anopheline populations were analyzed. Bimonthly human-bait and Shannon trap captures were conducted for 36 consecutive months (January 1997 through December 1999). A total of 5,205 adult anophelines belonging to five species were collected. Anopheles darlingi was the most frequently collected anopheline (61.4%), followed by An. albitarsis s.l. (35.4%), An. triannulatus. (2.5%), An. oswaldoi (0.4%), and An. evansae (0.2%). The water level and vegetation along the banks of the reservoir were crucial to the frequency of the various anopheline species. Climatic factors had a secondary influence. The reservoir's water-level stability, increased frequency of An. darlingi, and the arrival of gold prospectors were responsible for the increase in malaria cases.

[Microhimenopteran parasitoids of Chrysomya megacephala found in Brazil]. / Microhimenópteros parasitóides de Chrysomya megacephala.

The study was carried out with the purpose of identifying the main parasitoids of Chrysomya megacephala in the city of Rio de Janeiro, Brazil, given the importance of these flies as vectors of pathogenic agents in the urban environment. Samplings were conducted every week from August 1999 to July 2000. The substrate used to grow fly pupae and to trap parasitoids was decomposing meat. It was identified three species of microhimenopterans: Tachinaephagus zealandicus (Encyrtidae), Pachycrepoideus vindemiae (Pteromalidae) and Nasonia vitripennis (Pteromalidae). Further analysis will be performed in order to show the potential of these insects as agents in biological control programs.

[Muscoid dipterans as helminth eggs mechanical vectors at the zoological garden, Brazil]. / Dípteros muscóides como vetores mecânicos de ovos de helmintos em jardim zoológico, Brasil.

OBJECTIVE: To assess muscoid dipterae species who are able to carry helminth eggs and larvae and to evaluate the potential contamination of trapped dipterae. METHODS: The study was conducted in two different sites of the Zoological Garden of Rio de Janeiro from May 1996 to April 1998. Flies were captured weekly using traps containing putrefied fish, left out in the open for an hour at two sites in the zoo: Site 1 was next to the garbage and Site 2 was near the hippopotamus and birds of prey cages. Of the 41,080 flies captured, Chrysomya megacephala was the most representative species (69.34%), followed by Chrysomya albiceps (11.22%), Musca domestica (7.15%), Chrysomya putoria (4.52%), Fannia sp. ( 3.12%), Ophyra sp. ( 2.53%), and Atherigona orientalis (2.08%). Captured flies had their body surface washed out with distilled water and their gut dissected. RESULTS: Among the species studied, C. megacephala and M. domestica presented higher helminth eggs on their body surface and in their intestinal content. Ascaroidea and Trichinelloidea eggs prevailed in the intestinal content of C. megacephala. The helminth eggs found on the body surface and in the intestinal content were identified as Ascaris sp., Toxascaris sp., Toxocara sp., Trichuris sp., Capillaria sp., Oxyuridae, Trichostrongylidae and Acantocephala. Besides eggs it was also found helminth larvae on the body surface of flies. There were significant differences between the two different capture sites related to the number of helminth eggs found on the flies. CONCLUSIONS: Faeces of zoo animals frequently found in their cages and in the zoo garbage contributed to the proliferation of muscoid dipterans who play an important role in spreading helminth eggs, mainly by direct contact of the flies' body with the animals' food.

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.