Light-Emitting Diode (LED) Traps Improve the Light-Trapping of Anopheline Mosquitoes.

Numerous advantages over the standard incandescent lamp favor the use of light-emitting diodes (LEDs) as an alternative and inexpensive light source for sampling medically important insects in surveillance studies. Previously published studies examined the response of mosquitoes to different wavelengths, but data on anopheline mosquito LED attraction are limited. Center for Disease Control and Prevention-type light traps were modified by replacing the standard incandescent lamp with 5-mm LEDs, one emitting at 520 nm (green) and the other at 470 nm (blue). To test the influence of moon luminosity on LED catches, the experiments were conducted during the four lunar phases during each month of the study period. A total of 1,845 specimens representing eight anopheline species were collected. Anopheles (Nyssorhynchus) evansae (35.2%) was the most frequently collected, followed by An. (Nys.) triannulatus (21.9%), An. (Nys.) goeldii (12.9%), and An. (Nys.) argyritarsis (11.5%). The green LED was the most attractive light source, accounting for 43.3% of the individuals collected, followed by the blue (31.8%) and control (24.9%) lights. The LED traps were significantly more attractive than the control, independent of the lunar phase. Light trapping of anopheline mosquitoes was more efficient when the standard incandescent lamp was replaced with LEDs, regardless of the moon phase. The efficiency of LEDs improves light trapping results, and it is suggested that the use of LEDs as an attractant for anopheline mosquitoes should be taken into consideration when sampling anopheline mosquitoes.

Infestation of Brazilian Peridomiciliary Areas by Culicoides (Diptera: Ceratopogonidae) in Humid and Semihumid Climates.

This study investigates Culicoides infestation in peridomestic environments in two villages in Maranhão, one with hot and humid climate and the other with semihumid climate. We evaluated the composition, richness, abundance, and seasonality of species. We captured insects using CDC light traps installed in animal shelters once a month, from 6 pm to 6 am, for 24 mo (May 2012 to April 2014). In this study, 17 species were found. Of these, 10 occurred simultaneously in two areas; six were found only in hot and humid area, while one occurred only in the semihumid area. Species richness was higher in the hot and humid climate (16 species) than in the semihumid (11 species). The rank of abundance was uneven across areas: C. foxi, C. insignis, C. filariferus, C. ignacioi, and C. flavivenula were dominant in the hot and humid area, and C. ignacioi, C. foxi, C. filariferus, C. insignis, and C. boliviensis in the semihumid. Midges were more abundant in the rainy season in both areas. This result reveals a diversified fauna of midges, with variable abundance of rank according to the area, prevailing in the rainy season and in the Amazon area. It also highlights the need for health monitoring in order to contain the infestation by these insects in peridomestic environments, taking into account that some species can be effective vectors of arboviruses in the Amazon and northeastern Maranhão.

An Evaluation of Light-Emitting Diode (LED) Traps at Capturing Phlebotomine Sand Flies (Diptera: Psychodidae) in a Livestock Area in Brazil.

A study to evaluate the use of light-emitting diodes (LEDs) as an attractant for phlebotomine sand flies at two animal pens in a livestock area in Brazil was performed. Light-suction traps were operated overnight with the following light sources: green, blue, and incandescent (control) lights. In total, 22 individual collections were made at each site and 44 with each trap type. In total, 2,542 specimens belonging to 14 phlebotomine species were collected. The most abundant species in the light traps were Nyssomyia whitmani, Evandromyia evandroi, Micropygomyia goiana, Lutzomyia longipalpis, and Bichromomyia flaviscutellata Taking the two sites together, the green-LED light was the most attractive, followed by the blue and incandescent lights, and the difference between the green-LED and the control was statistically significant. Most species were green-biased at both sites, but some species-specific differences were observed. However, even with these differences, the standard incandescent light was outcompeted by LEDs. The green-LED-biased response observed in the present study, together with numerous advantages in favor of LEDs, suggests that the green-LED light source can be used as an effective substitute for the currently used incandescent bulb in monitoring traps for phlebotomine sand flies in Brazil.

Ecology of phlebotomines (Diptera: Psychodidae) in a transitional area between the Amazon and the Cerrado in the State of Maranhão, Brazil.

The Amazon rainforest and the Brazilian Cerrado both possess high phlebotomine diversity. The fragmentation of these habitats has resulted in the appearance of human cases of cutaneous leishmaniasis. In one altered area of mixed primary vegetation (forest and Cerrado) and its adjacent settlement in the northeast state of Maranhão, Brazil, evidence exists for the active transmission of cutaneous leishmaniasis. Accordingly, an entomological investigation was performed in both the forest and the settlement to compare the phlebotomine vector faunain each environment. The study was conducted from September 2009 to August 2010 in the municipality of Itapecuru Mirim in the state of Maranhão, Brazil. The phlebotomine species were captured using 24 light Center for Disease Control and Prevention traps that were placed in the forest and the settlement (peridomicile and intradomicile). The similarity between the phlebotomine compositions in the forest and those in the settlement was determined using a Principal Coordinate Analysis based on a dissimilarity matrix that was calculated using the Bray-Curtis index (relative abundance) and the Jaccard index (presence and absence of species). In total, 29 Lutzomyia species and one Brumptomyia species were collected. The phlebotomines were diverse and abundant in both the forest fragment (27 species, 4,606 specimens) and the settlement (22 species, 753 specimens). The most abundant species were L. infraspinosa (25%), L. davisi (21%), L. antunesi (21%), L. longipalpis (9%), L. saulensis (6%), L. flaviscutellata (5%), and L. wellcomei (4%). Some species were found strictly in the forest, other species were exclusive to the anthropic environment, and some species colonized both of the studied environments. The phlebotomines adaptation to these modified environments explains the autochthonous outbreak of cutaneous leishmaniasis.

Genetic differentiation in natural populations of Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae) with different phenotypic spot patterns on tergites in males.

Entomological surveys in the state of Maranhão have recorded morphologically distinct populations of Lutzomyia longipalpis (Lutz & Neiva). Some populations have one pair of spots (1S) on the fourth tergite, while others have two pairs (2S) on the third and fourth tergites of males. In the present study we investigated the degree of genetic polymorphism among four populations in the municipalities of Caxias, Codó and Raposa, in the state of Maranhão, Brazil, by using RAPD (Random Amplified Polymorphic DNA) markers. A total of 35 loci were identified, of which 30 were polymorphic. The highest polymorphism was observed with primer OPA 4, which produced 11 different profiles. Genetic diversity was assessed using grouping methods that produced a dendrogram in which the genotypes could be clearly separated into two main clades according to the number of spots on the male abdominal tergites. One cluster contained the populations from Caxias and Codó, and the other was formed by the populations from Raposa and Codó. The results of our RAPD analysis showed a clear separation between the populations with one and two pairs of spots. The epidemiologic significance of this genetic differentiation should be investigated in future studies.

The effect of fragmentation on phlebotomine communities (Diptera: Psychodidae) in areas of ombrophilous forest in São Luís, state of Maranhão, Brazil.

The aim of this study was to determine whether an edge effect could be observed in the structure and composition of phlebotomine assemblages in five forest fragments on São Luís Island. The study also investigated whether there were any differences in species along the forest edge-to-interior gradient and in species richness and abundance between the fragments studied. To capture the insects a transect was defined in each fragment, and eight light traps were set up at 15 m intervals from the edge. Phlebotomines were found in all fragments, and a total of 2972 specimens (1188 males and 1784 females) belonging to 24 species were collected. Of these, the most abundant was Lutzomyia antunesi (Coutinho), followed by Brumptomyia avellari (Costa Lima), L. infraspinosa (Mangabeira), L. flaviscutellata (Mangabeira), L. claustrei Abonnenc, Léger & Fauran, L. wellcomei (Fraiha, Shaw & Lainson), L. sordellii (Shannon & Del Ponte) and L. paraensis (Costa Lima). No significant differences were observed in the number of individuals or species along the edge-to-interior gradient. However, a higher distribution of some species in certain regions of the forest could be observed graphically. There was no correlation between fragment size and the number of species or individuals.

Population dynamics of euglossinae bees (Hymenoptera, Apidae) in an early second-growth forest of Cajual Island, in the state of Maranhão, Brazil.

A study was conducted in an early second-growth forest aiming at knowing the richness, relative abundance, seasonal distribution, and hourly frequency of euglossine bees, and their association with scent baits. Male bees were attracted to cineole, vanillin, methyl salicylate, and eugenol. The baits were hooked 1.5 m high and 6 m from one another. The specimens were collected from December 1997 to November 1998, once a month, from 7:00 to 17:00 h. A total of 339 male euglossine bees were caught, accounting for 19 species and four genera. The most common species was E. cordata, making up 69.9% of the individuals, followed by E. truncata (2.3%), E. violaceifrons, and E. smaragdina (2.1%). The most attractive scent was cineole, which baited 87% of the specimens and 73.7% of the species. Vanillin, the second most visited bait, eured 7.6% of the specimens and 26.3% of the species. E. surinamensis was only collected with this bait. Methyl salicylate and eugenol baited combined 2.6% of the specimens. However, by species numbers Methyl salicylate attracted 21% whereas eugenol was attractive for 15.8% of them. In general, the species were more abundantly found in the rainy season (January-June). The hourly activity data showed that the euglossine bees were attracted to the baits all day long, but at a higher frequency in the morning period, peaking between 8:00 and 10:00 h.

Population dynamics of Euglossinae bees (Hymenoptera, Apidae) in an early second-growth forest of Cajual Island, in the State of Maranhäo, Brazil

A study was conducted in an early second-growth forest aiming at knowing the richness, relative abundance, seasonal distribution, and hourly frequency of euglossine bees, and their association with scent baits. Male bees were attracted to cineole, vanillin, methyl salicylate, and eugenol. The baits were hooked 1.5 m high and 6 m from one another. The specimens were collected from December 1997 to November 1998, once a month, from 7:00 to 17:00 h. A total of 339 male euglossine bees were caughts, accounting for 19 species and four genera. The most common species was E. cordata, making up 69.9 percent of the individuals, followed by E. truncata (2.3 percent), E. violaceifrons, and E. smaragdina (2.1 percent). The most attractive scent was cineole, which baited 87 percent of the specimens and 73.7 percent of the species. Vanillin, the second most visited bait, eured 7.6 percent of the specimens and 26.3 percent of the species. E. surinamensis was only collected with this bait. Methyl salicylate and eugenol baited combined 2.6 percent of the specimens. However, by species numbers Methyl salicylate attracted 21 percent whereas eugenol was attractive for 15.8 percent of them. In general, the species were more abundantly found in the rainy season (January-June). The hourly activity data showed that the euglossine bees were attracted to the baits all day long, but at a higher frequency in the morning period, peaking between 8:00 and 10:00 h

Structure refinement of the aldehyde oxidoreductase from Desulfovibrio gigas (MOP) at 1.28 A.

The sulfate-reducing bacterium aldehyde oxidoreductase from Desulfovibrio gigas (MOP) is a member of the xanthine oxidase family of enzymes. It has 907 residues on a single polypeptide chain, a molybdopterin cytosine dinucleotide (MCD) cofactor and two [2Fe-2S] iron-sulfur clusters. Synchrotron data to almost atomic resolution were collected for improved cryo-cooled crystals of this enzyme in the oxidized form. The cell constants of a=b=141.78 A and c=160.87 A are about 2% shorter than those of room temperature data, yielding 233,755 unique reflections in space group P6(1)22, at 1.28 A resolution. Throughout the entire refinement the full gradient least-squares method was used, leading to a final R factor of 14.5 and Rfree factor of 19.3 (4sigma cut-off) with "riding" H-atoms at their calculated positions. The model contains 8146 non-hydrogen atoms described by anisotropic displacement parameters with an observations/parameters ratio of 4.4. It includes alternate conformations for 17 amino acid residues. At 1.28 A resolution, three Cl- and two Mg2+ ions from the crystallization solution were clearly identified. With the exception of one Cl- which is buried and 8 A distant from the Mo atom, the other ions are close to the molecular surface and may contribute to crystal packing. The overall structure has not changed in comparison to the lower resolution model apart from local corrections that included some loop adjustments and alternate side-chain conformations. Based on the estimated errors of bond distances obtained by blocked least-squares matrix inversion, a more detailed analysis of the three redox centres was possible. For the MCD cofactor, the resulting geometric parameters confirmed its reduction state as a tetrahydropterin. At the Mo centre, estimated corrections calculated for the Fourier ripples artefact are very small when compared to the experimental associated errors, supporting the suggestion that the fifth ligand is a water molecule rather than a hydroxide. Concerning the two iron-sulfur centres, asymmetry in the Fe-S distances as well as differences in the pattern of NH.S hydrogen-bonding interactions was observed, which influences the electron distribution upon reduction and causes non-equivalence of the individual Fe atoms in each cluster.

Sandflies (Diptera: Psychodidae) of the Amazônia of Maranhão. V. Seasonal occurrence in ancient colonization area and endemic for cutaneous leishmaniasis.

In this paper, the seasonal abundance of 25 sandfly species (1 of the Brumptomyia genus and 24 of the Lutzomyia genus) found at P1V5, municipal district of Buriticupu, Maranhão State, is discussed. The capture was carried out from 18:00 P.M. to 6:00 A.M., once a month, from January to December 1996. CDC light traps were set up in the forest, in the peri and intradomicile environments. Five species were only found in the rainy season (January to June), being represented by one or two individuals; eight species occurred only in the dry season (July to December) and eleven species appeared in both seasons. The most frequent species in the dry period were: L. whitmani (26.3%), L. serrana (23%), L. choti (22.8%), L. evandroi (7.5%), L. longipalpis (5.8%), L. termitophila (3.3%), L. shannoni (3%) and L. migonei (2.5%). In the rainy season, L. whitmani was the prevailing species (74%), followed by L. termitophila (4%), L. umbratilis (3.4%), L. serrana (2.8%), L. evandroi (2,8%) and L. claustrei (2.4%). L. whitmani was thought to be an annual species, occurring in the entire year of study. The others species, with exception to L. serrana and L. evandroi, showed a seasonal, punctual or peripheric pattern.

Emerging Chagas disease: trophic network and cycle of transmission of Trypanosoma cruzi from palm trees in the Amazon.

A trophic network involving molds, invertebrates, and vertebrates, ancestrally adapted to the palm tree (Attalaea phalerata) microhabitat, maintains enzootic Trypanosoma cruzi infections in the Amazonian county Paço do Lumiar, state of Maranhão, Brazil. We assessed seropositivity for T. cruzi infections in the human population of the county, searched in palm trees for the triatomines that harbor these infections, and gathered demographic, environmental, and socioeconomic data. Rhodnius pictipes and R. neglectus in palm-tree frond clefts or in houses were infected with T. cruzi (57% and 41%, respectively). Human blood was found in 6.8% of R. pictipes in houses, and 9 of 10 wild Didelphis marsupialis had virulent T. cruzi infections. Increasing human population density, rain forest deforestation, and human predation of local fauna are risk factors for human T. cruzi infections.

[Hourly frequency and seasonality of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) on São Luís Island, Maranhão, Brazil]. / Freqüência horária e sazonalidade de Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) na Ilha de São Luís, Maranhão, Brasil.

This article presents the hourly and seasonal distribution of the Lutzomyia longipalpis sand fly captured on São Luís Island, Maranhão State. A total of 11,200 specimens were captured during monthly use of CDC light traps indoors and in animal sheds, between 6:00 PM and 6:00 AM, in 1996 and 1997. The sand fly behaved as an annual species, with a high frequency year-round, while it was most abundant during the rainy season (57.2%) as compared to the dry season (42.8%). The highest frequencies during the rainy season occurred in January and April and in the dry season in July and November. The species was found all night long, mainly between 6:00 PM and 10:00 PM in animal sheds and between 8:00 PM and 2:00 AM indoors.

[Anopheles species in the municipality of Pinheiro (Maranhão), endemic area of malaria]. / Espécies de Anopheles no município de Pinheiro (Maranhão), área endêmica de malária.

The Anophelae species of the municipal district of Pinheiro, Maranhão State, Brazil, were studied, considering their variety, relative abundance, seasonal fluctuation, preference by the peri and intra domiciles as well as the hours of hematophagism. The females were captured using human bait, on a monthly basis from May/1998 to April/1999, from 6 p.m. to 6 a.m. A total of 1,321 specimens of 10 species were captured, all belonging to the subgenus Nyssorhynchus. The most frequent species were A. argyritarsis (62%), A. darlingi (21.7%), A. albitarsis (4.5%), A. galvaoi (4.0%), A. triannulatus (3.1%) and A. evansae (2.8%). The species A. nuneztovari, A. braziliensis, A. rondoni and A. strodei together represented 1.9%. The anophelines occurred all year round, with no significant difference in the number of specimens captured between the rainy (51.7%) and dry season (48.3%). The frequency of the females in the peridomicile was significantly higher (p < 0.01) (82%), than in the intradomicile (18%), preferring to suck blood at dusk and in the first hours of the night.

[Phlebotominae (Diptera: Psychodidae) of Lagoas, a city of Buriticupu, Amazonia of Maranhão. I. The richness and relative abundance of the species in an area of recent colonization]. / Phlebotominae (Diptera: Psychodidae) de Lagoas, município de Buriticupu, Amazônia Maranhense. I--Riqueza e abundância relativa das espécies em área de colonização recente.

In this study the diversity of the species and relative abundance of the sand flies in the Amazonian community of Lagoas, in Buriticupu, Maranhão State, was determined. The study consisted of adult sandflies captured with CD light-traps, Shannon-trap and manual aspiration tube, between 18 PM and 6 AM, once a month, from December/95 to January/97, in a forest fragment and in the domestic environment (peri and intra). In all, 9,393 specimens were captured (4,302 males and 5,140 females) distributed among 38 species (1 Brumptomyia and 37 Lutzomyia). The diversity and abundance of species was higher in the forest, followed by the peri and intra. The predominance in the wild ambient is a consequence of the potentialities found in the remaining fragments of the forest which have survived the lumber yard exploitation and agricultural activities. In the forest environment Lutzomyia whitmani (64.9%), L. migonei (27%) and L. serrana (3.6%) were the most frequent species. In the peri and intra domicile L. evandroi predominated (55.4% and 97.9%). The species, L. whitmani (33.4%) and L. migonei (6.4%), were important in the peri domicile. The peridomestic habit of 7.7% of the sand flies showed the greatest epidemiologic importance, due to the existence of patients with leishmaniasis ulcers, who believe they were infected near their habitations.

[Sandflies (Diptera, psychodidae) in a secondary forest area in the Paco do Lumiar city, Maranhao, Brazil: a leishmaniasis transmission area]. / Flebotomíneos (Diptera, Psychodidade) de capoeira do Município do Paço do Lumiar, Estado do Maranhão, Brasil. Area de transmissão de leishmaniose.

This paper analyzes the wealth of species, relative abundance, seasonal fluctuation, and nocturnal activity of sandflies. The field survey was conducted in a "capoeira" (secondary forest) area in the county of Paço do Lumiar, Maranhão, where cutaneous and transmission of visceral leishmaniasis frequently occurs. Sandflies were captured by CDC-type light traps from 6:00 PM to 6:00 AM, once a month, from March 1997 to February 1998. A total of 489 specimens were collected (251 males and 238 females), distributed among 10 species: Lutzomyia antunesi (45.19%), Lutzomyia whitmani (29.4%), Lutzomyia longipalpis (7.56%), Lutzomyia sordelli (6.34%), Lutzomyia flaviscutellata (4.5%), Brumptomyia avellari (4.09%), Lutzomyia evandroi (1.85%), Lutzomyia umbratilis (0.61%), Lutzomyia corossoniensis (0.41%), and Lutzomyia trispinosa (0.41%). The sandflies were present year round, with higher abundance during the rainy season. They were present in all intervals studied, with the highest frequency between 12:00 PM and 1:00 AM (31%).

[Distribution of Aedes aegypti and dengue in the State of Maranhão, Brazil]. / Distribuição do Aedes aegypti e do dengue no Estado do Maranhão - Brasil.

Dengue and Aedes aegypti are widespread in the State of Maranhão. During 1995, 87 of the 136 of the State's counties, including 176 towns and 480,687 households, were studied, of which 30 counties (34. 4%), 118 towns (67.0%) and 10,357 households (2.1%) were positive for Aedes aegypti. The positive counties are distributed as follow: 3 on São Luís Island, 7 in the Amazonia of Maranhão, 12 in the southern zone of the cerrados or savannas, and 5 in the mixed forest/savanna/palm grove zone. One positive county for Ae. aegypti was located in each of the following: alluvial fields, forest/palm grove, and sand dune/shoals areas. The Ae. aegypti-positive household rates were higher in the Amazonia of Maranhão (3.5%) and on São Luís Island (2.5%), because they are the most heavily traveled migratory and trade routes between Maranhão and neighboring states and are also the State's main economic centers. Household infestation rates for Ae. aegypti and reported dengue case rates were higher during the rainy season, showing the importance of rain in forming prime breeding sites for Aedes and spreading dengue.

[Sandflies (Diptera, Psychodidae) from an endemic leishmaniasis area in the cerrado region of the State of Maranhão, Brazil]. / Flebotomíneos (Diptera, Psychodidae) de área endêmica de leishmaniose na região dos cerrados, Estado do Maranhão, Brasil.

This article presents a list of ten sandfly species from the genus Lutzomyia França, 1924 found in the counties of Aldeias Altas, Capinzal do Norte, Caxias, Codó, Coelho Neto, Timbiras, Timon and Tuntum in northeastern Maranhão, Brazil. Presence of sandflies was associated with cases of visceral and cutaneous leishmaniasis. Some 377 specimens were captured indoors with CDC light traps and 1491 specimens in the peridomicile. The species were: Lutzomyia cortelezii, Lutzomyia evandroi, Lutzomyia goiana, Lutzomyia intermedia, Lutzomyia lenti, Lutzomyia longipalpis, Lutzomyia longipennis, Lutzomyia squamiventris, Lutzomyia termitophila and Lutzomyia whitmani. The most abundant species was L. longipalpis (67. 4% and 70.2%) followed by L. whitmani (31.0% and 24.7%). L. longipalpis was captured both indoors and outdoors in all the months studied.

[Phlebotomus (Diptera, Phlebotominae) from Saint Luis Island, Maranhão Gulf region, Brazil]. / Flebótomos (Diptera, Phlebotominae) da Ilha de São Luis, zona do Golfão Maranhense, Brasil.

This study lists 32 species of sand flies, 1 of them belonging to the genus Brumptomyia and 31 to the genus Lutzomyia, distributed among the following subgenera: Psychodopygus (6), Nyssomyia (5), Pressatia (3), Evandromyia (2), Psathyromyia (2), Sciopemyia (2), Lutzomyia (1), Micropygomyia (1), Viannamyia (1), and the groups Oswaldoi (5) and Migonei (3). The sand flies were captured in the wild (forest) and in peridomicile (pigpen, hen house and stable) and intradomicile (bedroom) areas from 06:00 PM to 06:00 AM, once a month, for 4 years on the Island of São Luis, Maranhão. All species sampled were present in the forest. Among them, 16 were found in the peridomicile, while 11 were found inside the houses. A total of 22,581 specimens were captured, 65.1% of them in the peridomicile, 17.5% in the forest and 17.4% in the intradomicile. The most common species was Lutzomyia longipalpis (66.4% of the captured specimens), followed by Lutzomyia whitmani (24%) and Lutzomyia evandroi (5.9%). The remaining 29 species represented 3.7% of the total sample.

[Species of Anopheles (Culicidae, Anophelinae) in a malaria-endemic area, Maranhão, Brazil]. / Espécies de Anopheles (Culicidae, Anophelinae) em área endêmica de malária, Maranhão, Brasil.

INTRODUCTION: The study of the seasonal fluctuation, nocturnal activity, relative abundance and the richness of Anopheles species in anthropic environment is essential to the understanding of the their bioecology and to the surveillance program of malaria control. METHODS: The Anopheles species were studied from 6 P.M. to 6 A.M., once a month, for one year, from October 1996 to September 1997, in the municipal district of Raposa, of the São Luís island, Maranhão state. The basic method was the capture of female specimens on human baits in peri and intradomicile sites by means of aspiration tube and guided luminous focus. RESULTS: A total of 1.407 specimens were collected and distributed as follow: Anopheles aquasalis (82% of the sample), Anopheles galvaoi (10,2%), Anopheles albitarsis (6,4%), Anopheles evansae, Anopheles nuneztovari, and Anopheles triannulatus davisi (the last three represented together 1, 4%). The anophelines occurred all year round, mainly in the rainy period, being more frequent in the intra (75,3%) than in the peridomicile site (24,7%), showing a clear preference to suck blood in the evening. CONCLUSION: The behavioural variation of Anopheles shows that the different species are becoming adapted to closeness to human habitations, in the rural zone of the São Luis island.