Host-feeding Preference of Anopheles Species under Prolonged Use of Insecticide-treated Bed Nets in Kamuli District, Uganda: Implications for Vector Control

Background: The blood-feeding patterns are crucial in incriminating disease vectors as well as facilitating the design and consolidation of effective vector control interventions in an area. Objective: This study aimed to establish if prolonged use of insecticide-treated bed nets (ITNs) caused a shift in the preferred hosts of the common malaria vectors as the hosts were under the bed net. Such a shift would render ITNs less effective and would probably explain the continued morbidity and mortality due to malaria in the highly endemic Kamuli district. Methods: A total of 3,519 indoor and outdoor human biting female Anopheles gambiae sensu latoand An. funestusmosquitoes were collected from 48 householdsusing human-baited bed net traps. All 187 indoor resting blood-fed anophelines collected were tested by direct enzyme-linked immunosorbent assay (ELISA) for blood meal host identification. Of these, 73 mid guts came from 24 households in villages with a 69% ITNs coverage, while 114 mid guts were from 24 households in non-ITN villages. Results: Blood meal hosts were identified in only 10.96% (n = 8) and 14.91% (n = 17) of the Anophelesblood meals from the intervention and non-intervention zones, respectively. Other blood meals could not be clearly identified. Eight (100%) blood meals in the intervention zone were from humans, while in the non-intervention zone, 15 (88.24%), one (5.88%) and one (5.88%) came from humans, cattle and goat, respectively. These findings demonstrated that the malaria vectors in Kamuli district are anthropophilic, with nearly all the mosquitoes collected from both zones feeding on humans during every blood meal (p = 0.82). This indicated high vector-human contacts, and thus implicating these species as important in the transmission of Plasmodiumspecies and probably other infections. Conclusion: The use of insecticide-treated bed nets is effective for controlling malaria vectors inside houses, evoking universal coverage of houses in the area.

First record of Anastrepha bahiensis Lima (Diptera: Tephritidae) infesting fruits of Averrhoa carambola L. in the eastern Amazon, Brazil

ABSTRACT We report for the first time field infestation under natural conditions by Anastrepha bahiensis on star fruit (Averrhoa carambola L., Oxalidaceae) in the state of Pará, Eastern Amazon, Brazil. This report reinforces the importance of field infestation studies on fruit flies in the Brazilian Amazon.

Parasitism of Diachasmimorpha longicaudata (Ashmead) on two fruit fly species / Parasitismo de Diachasmimorpha longicaudata (Ashmead) em duas espécies de moscas-das-frutas

The aim of the present study was to investigate the parasitism of two fruit fly species by different Diachasmimorpha longicaudata strains. Females of two parasitoid strains were reared on Ceratitis capitata or Anastrepha fraterculus that were conditioned in adapted containers. Individual parasitoids were offered 20 larvae for 1 h, using no-choice (20 C. capitata or 20 A. fraterculus) or free-choice (10 of each species) assays. Parasitism was verified by counting scars, and the pupae were classified as non-parasitized (no scars), parasitized (one scar), or superparasitized (multiple scars). Parasitism intensity was compared by evaluating the proportions of non-parasitized, parasitized, and superparasitized larvae. Parasitism intensity and scar frequency were analyzed as functions of host species and parasitoid strain, using chi-square tests. In the non-choice tests, females of both parasitoid strains parasitized the larvae, regardless of host species. However, when the parasitoids had a choice, they preferred to superparasitize A. fraterculus larvae, which are larger than C. capitata larvae. In addition, the female parasitoids parasitized most of the host larvae, regardless of parasitoid strain or host species. However, the frequency of non-parasitized pupae was higher when the offered host species was different from the one in which the parasitoid was reared, and the frequency of superparasitized pupae was higher when the offered host species was the same as the one in which the parasitoid was reared.(AU)

O objetivo deste trabalho foi avaliar o parasitismo de larvas de Tephritidae por duas linhagens de Diachasmimorpha ­longicaudata em duas espécies de mosca-das-frutas. Foram utilizadas fêmeas do parasitoide criadas sobre Ceratitis capitata ou Anastrepha fraterculus acondicionadas em gaiolas adaptadas. Para cada fêmea foram oferecidas 20 larvas durante 1 hora, em ensaio com chance de escolha (20 C. capitata ou 20 A. fraterculus) e sem chance de escolha (10 larvas de cada espécie). Após o parasitismo, o número de cicatrizes foi verificado e os pupários classificados como: não parasitados (ausência de cicatrizes), parasitados (presença de uma cicatriz) e superparasitados (duas ou mais cicatrizes). A intensidade de parasitismo foi avaliada por meio da proporção de larvas não parasitadas, parasitadas ou superparasitadas. As variáveis intensidade de parasitismo e frequência de cicatrizes em virtude do hospedeiro e da linhagem do parasitoide foram analisadas quanto à distribuição de frequência utilizando-se o teste qui-quadrado. No teste sem escolha, independentemente da espécie hospedeira, as fêmeas das duas linhagens parasitaram as larvas oferecidas e, quando tiveram escolha, preferiram superparasitar larvas de A. fraterculus, que são maiores que as de C. capitata. A frequência de pupários sem cicatriz foi maior quando o hospedeiro oferecido foi diferente daquele em que a fêmea foi criada. Independentemente da linhagem do parasitoide, as fêmeas parasitam a maioria das larvas hospedeiras das duas espécies, mas discriminam o hospedeiro, preferindo superparasitar a espécie na qual foi criada o hospedeiro. A. fraterculus foi o preferido para postura de fêmeas.(AU)

Diversity and distribution of vascular epiphytes in an insular Brazilian coastal forest

The study was carried out in a 3 000m2 area of coastal Atlantic rain forest at Ilha do Mel island (25o30’’S 48o23’W), on 100 assorted trees separated into 2 meter-high strata starting from the ground. In each stratum all of the occurring epiphytic species were recorded. The sampled species were grouped into three categories: exclusive, preferential, and indifferent, according to their abundance in each strata, and selective, preferential and indifferent, according to abundance on the forophytes. Intermediate strata registered the highest diversity. Six species were considered exclusive to one or two strata, 15 were restricted to some strata and 5 presented a broad distribution. No epiphytic species showed uniform horizontal distribution on the area. The epiphyte richness in a host tree varied from zero to 30. Regarding to fidelity on host tree species, few selective or preferential, and mainly indifferent epiphyte species, were found. A total of 82 epiphyte species were sampled in the surveyed tree, and the Wittaker plot indicate a highly dominant assemblage. Rev. Biol. Trop. 57 (3): 749-759. Epub 2009 September 30.

El estudio se realizó en un área 3 000 m2 de bosque atlántico húmedo en una isla brasileña, Ilha do Mel (25o30’’ S 48o23’ W). Seleccionamos 100 árboles de las 10 principales especies y las dividimos en estratos de dos metros a partir de la superficie del suelo. En cada estrato registramos todas las especies epífitas observadas. Las especies muestreadas fueron agrupadas en tres categorías: exclusivas, preferenciales, e indiferentes (según su abundancia en los estratos), y selectivas, preferenciales e indiferentes (según su abundancia en los árboles). Los estratos intermedios registraron las más altas diversidades. Seis especies fueron consideradas exclusivas a uno o dos estratos, 15 estuvieron limitadas a algunos estratos y 5 presentaron amplia distribución. Para ninguna especie epífita hubo distribución horizontal uniforme. La riqueza de las epífitas en un forofito varió de cero a 30 especies. Según la fidelidad de las epífitas en los árboles, registramos pocas especies selectivas o preferenciales y muchas indiferentes. En los 100 árboles examinados encontramos 82 especies de epífitas, y el diagrama del Wittaker indicó alta dominancia de unas pocas especies.

Preferência alimentar de Lutzomyia longipalpis (Lutz & Neiva, 1912) em área de transmissão de leishmaniose visceral em Mato Grosso / Feeding preference of Lutzomyia longipalpis (Lutz & Neiva, 1912) in transmission area of visceral leishmaniasis in Mato Grosso

O estudo dos hábitos alimentares e do conteúdo intestinal dos flebotomíneos permite a identificação dos hospedeiros, indicando os potenciais reservatórios das leishmanias. Este trabalho objetivou determinar a preferência alimentar de Lutzomyia longipalpis e sua relação com a transmissão da leishmaniose visceral. As capturas mensais foram realizadas em área de transmissão de leishmaniose visceral, município de Várzea Grande, Estado de Mato Grosso, no período de janeiro de 2004 a junho de 2006, utilizando-se armadilhas de luz CDC. Foram capturadas 2.376 fêmeas de Lutzomyia longipalpis, das quais 104 (4,4 por cento) estavam ingurgitadas, sendo 32 (30,8 por cento) capturadas no intradomicílio e 72 (69,2 por cento) no peridomicílio. Após reação de precipitina, observou-se que as fêmeas de Lutzomyia longipalpis alimentaram-se preferencialmente em aves (30,8 por cento) e roedores (21,2 por cento), mas também foram encontradas fêmeas alimentadas de sangue de humanos, gambás, bois, cavalos e cães, demonstrando o caráter oportunista da espécie.

Studies on the feeding habits and intestinal content of sandflies make it possible to identify hosts, thereby indicating potential reservoirs for Leishmania. The present study had the aim of determining the feeding preferences of Lutzomyia longipalpis and its relationship with the transmission of visceral leishmaniasis. Specimens were caught every month in a transmission area of visceral leishmaniasis, in the municipality of Várzea Grande, State of Mato Grosso, from January 2004 to June 2006, using CDC light traps. 2,376 females of Lutzomyia longipalpis were caught, of which 104 (4.4 percent) were engorged. Among these, 32 (30.8 percent) were caught inside homes and 72 (69.2 percent) in areas surrounding homes. From the precipitin reaction, it was observed that Lutzomyia longipalpis females fed preferentially on birds (30.8 percent) and rodents (21.2 percent), but they were also found to have fed on blood from humans, opossums, oxen, horses and dogs, thus demonstrating the opportunist nature of this species.

Does the presence of weeds affect Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) infestation on tomato plants in a semi-arid agro-ecosystem? / A presença de plantas invasoras afeta a infestação de tomateiros por Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) em um agro-ecossistema do semi-árido?

Integrated Bemisia tabaci (Gennadius) management requires quantitative knowledge on the mechanisms of persistence of pest populations in non-commercial host plants. We investigated B. tabaci oviposition preference among tomato and four weed species, and the insect population fluctuation under field conditions in the semi-arid region. At weekly intervals, we determined the level (number of eggs and nymphs per leaf) and the density of infestation (number of eggs and nymphs per leaf area) in all species. We observed an oviposition preference gradient among the species, with different degrees of attractiveness; Acanthospermum hispidum was the most infested species whereas Amaranthus deflexus was the least infested one. We also detected a significantly higher infestation on tomato when planted solely, which indicates a dilution effect on tomato infestation in the presence of weeds. Weeds can act as important reservoirs for whiteflies and/or their natural enemies or even as viral sources for cultivated plants. Their incorporation in integrated B. tabaci management programs depends on how those variables can be manoeuvred for the reduction of insect damage.

O manejo integrado de Bemisia tabaci (Gennadius) exige o conhecimento quantitativo dos mecanismos de persistência de populações em hospedeiros não comerciais. Este trabalho investigou a preferência para oviposição de B. tabaci entre tomate e quatro espécies de plantas invasoras, e a flutuação populacional do inseto em condições de campo no semi-árido nordestino. Semanalmente, foram determinados o nível (número de ovos e ninfas por folha) e a densidade de infestação (número de ovos e ninfas por área foliar) nas cinco espécies. Observamos diferentes graus de atratividade, formando um gradiente de preferência para oviposição entre as espécies, sendo Acanthospermum hispidum a espécie mais infestada e Amaranthus deflexus a menos infestada. Foi detectada ainda uma infestação significativamente mais elevada em parcelas contendo apenas tomateiros, sugerindo um efeito de diluição da infestação do tomateiro quando na presença de invasoras. Plantas invasoras podem representar importantes reservatórios para a mosca branca e/ou seus inimigos naturais, ou ainda fontes de inóculo viral para plantas cultivadas. Sua inserção em programas de manejo integrado de B. tabaci em tomateiro depende de como estes fatores podem ser manipulados para a redução dos danos causados pelo inseto.