RESUMO

BACKGROUND: The southern green stinkbug (Nezara viridula) is a mayor pest of soybean. However, the mechanism underlying stinkbug resistance to soybean defenses is yet ignored. Although gut bacteria could play an essential role in tolerating plant defenses, most studies testing questions related to insect-plant-bacteria interactions have been performed in laboratory condition. Here we performed experiments in laboratory and field conditions with N. viridula and its gut bacteria, studying gut lipid peroxidaxion levels and cysteine activity in infected and unifected nymphs, testing the hypothesis that feeding on field-grown soybean decreases bacterial abundance in stinkbugs. RESULTS: Gut bacterial abundance and infection ratio were higher in N. viridula adults reared in laboratory than in those collected from soybean crops, suggesting that stinkbugs in field conditions may modulate gut bacterial colonization. Manipulating gut microbiota by infecting stinkbugs with Yokenella sp. showed that these bacteria abundance decreased in field conditions, and negatively affected stinkbugs performance and were more aggressive in laboratory rearing than in field conditions. Infected nymphs that fed on soybean pods had lower mortality, higher mass and shorter development period than those reared in the laboratory, and suggested that field conditions helped nymphs to recover from Yokenella sp. infection, despite of increased lipid peroxidation and decreased cysteine proteases activity in nymphs' guts. CONCLUSIONS: Our results demonstrated that feeding on field-grown soybean reduced bacterial abundance and infection in guts of N. viridula and highlighted the importance to test functional activities or pathogenicity of microbes under realistic field conditions prior to establish conclusions on three trophic interactions. © 2022 Society of Chemical Industry.

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Abstract Carabids are recognized worldwide as biological control agents of agricultural pests. The objective was to compare the life cycle of Abaris basistriata Chaudoir (Coleoptera: Carabidae) on three substrates: soil, fine vermiculite, or paper napkins. The biological cycle of A. basistriata presented different durations in soil and paper. The viability of eggs and larvae survival of the first and second instars were similar on all three substrates, while the third instar and pupa in the soil presented higher survival when compared with vermiculite and paper. The soil substrate was more favorable for the longevity of the carabid beetle. Abaris basistriata showed a shorter pre-oviposition period and a higher oviposition and post-oviposition period in the soil. Fecundity and fertility were higher when A. basistriata was reared on soil. The soil was most favorable substrate for rearing of A. basistriata in the laboratory. This information may make this species useful for the biological control.

Resumo Os carabídeos são reconhecidos mundialmente como agentes de controle biológico de pragas agrícolas. O objetivo foi comparar o ciclo de vida de Abaris basistriata Chaudoir (Coleoptera: Carabidae) em três substratos: solo, vermiculita fina, ou guardanapos de papel. O ciclo biológico de A. basistriata apresentou diferentes durações no solo e no papel. A viabilidade dos ovos e a sobrevivência das larvas do primeiro e segundo instares foram semelhantes nos três substratos, enquanto que o terceiro instar e a pupa apresentaram maior sobrevivência no solo quando comparados com vermiculita e papel. O substrato solo foi mais favorável à longevidade do carabídeo. Abaris basistriata mostrou menor período de pré-oviposição e maior período de oviposição e pós-oviposição no solo. A fecundidade e a fertilidade foram maiores quando A. basistriata foi criado no solo. O solo foi o substrato mais favorável para a criação de A. basistriata no laboratório. Estas informações são importantes e podem tornar essa espécie útil para o controlo biológico.

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The blue gum chalcid, Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae), causes galls on Eucalyptus spp. leaf midribs, petioles and stems. Biological aspects need to be studied to assist in developing management strategies and to maintain this insect in the laboratory to rear the parasitoid Selitrichodes neseri Kelly & La Salle (Hymenoptera: Eulophidae) that depends on having a supply of Eucalyptus seedlings infested by L. invasa. We evaluated the longevity and survival of L. invasa individual non reproductive females fed with six different diets (pure honey, 50% honey solution, pure honey plus eucalyptus leaves, eucalyptus leaves, distilled water, or no food) and seven different temperatures (10, 14, 18, 22, 26, 30 and 34 °C). Leptocybe invasa fed with 50% honey solution and reared at 14 or 18 °C showed the greatest longevity and survival.

RESUMO

Stenochironomus munteanpurin sp. n. is described and illustrated in all life stages, except eggs, from Brazil. The male is very similar to Stenochironomus quadrinotatus Borkent, 1984 due to same overall pattern of pigmentation. The new species can be distinguished from the other related species principally in immature stages: larva with labral lamella arranged in two groups with one or two conical-shaped teeth, spicules of pecten epipharyngis arranged in a row, unequal and irregularly distributed sizes, SI bifurcated, SII pinnate, SIII pinnate setae and, larval exuviae is compacted; pupa with shagreens being in all TI, less number of hooklets in TII, TVII without shagreens and presence of shagreen in conjunctive III/IV and IV/V. Adult male is very similar to the one of S. quadrinotatus but can be distinguished by combination of the TIX with more than 25 setae medially and phallapodeme curved anteriorly. The new species were collected in the following Brazilian states: Rio de Janeiro, Santa Catarina, Bahia and Acre.

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RESUMO

Carabids are recognized worldwide as biological control agents of agricultural pests. The objective was to compare the life cycle of Abaris basistriata Chaudoir (Coleoptera: Carabidae) on three substrates: soil, fine vermiculite, or paper napkins. The biological cycle of A. basistriata presented different durations in soil and paper. The viability of eggs and larvae survival of the first and second instars were similar on all three substrates, while the third instar and pupa in the soil presented higher survival when compared with vermiculite and paper. The soil substrate was more favorable for the longevity of the carabid beetle. Abaris basistriata showed a shorter pre-oviposition period and a higher oviposition and post-oviposition period in the soil. Fecundity and fertility were higher when A. basistriata was reared on soil. The soil was most favorable substrate for rearing of A. basistriata in the laboratory. This information may make this species useful for the biological control.(AU)

Os carabídeos são reconhecidos mundialmente como agentes de controle biológico de pragas agrícolas. O objetivo foi comparar o ciclo de vida de Abaris basistriata Chaudoir (Coleoptera: Carabidae) em três substratos: solo, vermiculita fina, ou guardanapos de papel. O ciclo biológico de A. basistriata apresentou diferentes durações no solo e no papel. A viabilidade dos ovos e a sobrevivência das larvas do primeiro e segundo instares foram semelhantes nos três substratos, enquanto que o terceiro instar e a pupa apresentaram maior sobrevivência no solo quando comparados com vermiculita e papel. O substrato solo foi mais favorável à longevidade do carabídeo. Abaris basistriata mostrou menor período de pré-oviposição e maior período de oviposição e pós-oviposição no solo. A fecundidade e a fertilidade foram maiores quando A. basistriata foi criado no solo. O solo foi o substrato mais favorável para a criação de A. basistriata no laboratório. Estas informações são importantes e podem tornar essa espécie útil para o controlo biológico.(AU)

RESUMO

Abstract Carabids are recognized worldwide as biological control agents of agricultural pests. The objective was to compare the life cycle of Abaris basistriata Chaudoir (Coleoptera: Carabidae) on three substrates: soil, fine vermiculite, or paper napkins. The biological cycle of A. basistriata presented different durations in soil and paper. The viability of eggs and larvae survival of the first and second instars were similar on all three substrates, while the third instar and pupa in the soil presented higher survival when compared with vermiculite and paper. The soil substrate was more favorable for the longevity of the carabid beetle. Abaris basistriata showed a shorter pre-oviposition period and a higher oviposition and post-oviposition period in the soil. Fecundity and fertility were higher when A. basistriata was reared on soil. The soil was most favorable substrate for rearing of A. basistriata in the laboratory. This information may make this species useful for the biological control.

Resumo Os carabídeos são reconhecidos mundialmente como agentes de controle biológico de pragas agrícolas. O objetivo foi comparar o ciclo de vida de Abaris basistriata Chaudoir (Coleoptera: Carabidae) em três substratos: solo, vermiculita fina, ou guardanapos de papel. O ciclo biológico de A. basistriata apresentou diferentes durações no solo e no papel. A viabilidade dos ovos e a sobrevivência das larvas do primeiro e segundo instares foram semelhantes nos três substratos, enquanto que o terceiro instar e a pupa apresentaram maior sobrevivência no solo quando comparados com vermiculita e papel. O substrato solo foi mais favorável à longevidade do carabídeo. Abaris basistriata mostrou menor período de pré-oviposição e maior período de oviposição e pós-oviposição no solo. A fecundidade e a fertilidade foram maiores quando A. basistriata foi criado no solo. O solo foi o substrato mais favorável para a criação de A. basistriata no laboratório. Estas informações são importantes e podem tornar essa espécie útil para o controlo biológico.

RESUMO

Abstract Carabids are recognized worldwide as biological control agents of agricultural pests. The objective was to compare the life cycle of Abaris basistriata Chaudoir (Coleoptera: Carabidae) on three substrates: soil, fine vermiculite, or paper napkins. The biological cycle of A. basistriata presented different durations in soil and paper. The viability of eggs and larvae survival of the first and second instars were similar on all three substrates, while the third instar and pupa in the soil presented higher survival when compared with vermiculite and paper. The soil substrate was more favorable for the longevity of the carabid beetle. Abaris basistriata showed a shorter pre-oviposition period and a higher oviposition and post-oviposition period in the soil. Fecundity and fertility were higher when A. basistriata was reared on soil. The soil was most favorable substrate for rearing of A. basistriata in the laboratory. This information may make this species useful for the biological control.

Resumo Os carabídeos são reconhecidos mundialmente como agentes de controle biológico de pragas agrícolas. O objetivo foi comparar o ciclo de vida de Abaris basistriata Chaudoir (Coleoptera: Carabidae) em três substratos: solo, vermiculita fina, ou guardanapos de papel. O ciclo biológico de A. basistriata apresentou diferentes durações no solo e no papel. A viabilidade dos ovos e a sobrevivência das larvas do primeiro e segundo instares foram semelhantes nos três substratos, enquanto que o terceiro instar e a pupa apresentaram maior sobrevivência no solo quando comparados com vermiculita e papel. O substrato solo foi mais favorável à longevidade do carabídeo. Abaris basistriata mostrou menor período de pré-oviposição e maior período de oviposição e pós-oviposição no solo. A fecundidade e a fertilidade foram maiores quando A. basistriata foi criado no solo. O solo foi o substrato mais favorável para a criação de A. basistriata no laboratório. Estas informações são importantes e podem tornar essa espécie útil para o controlo biológico.

RESUMO

With more than 140 potential vectors of Chagas disease, it is important to better know the biology and especially the vectorial capacity of the triatomine species which live in the surroundings of human dwellings. In Bolivia where 17 triatomine species are reported, the principal vector is Triatoma infestans. In some valleys of the department of La Paz where T. infestans is not present, a new species (Triatoma boliviana) was described in 2007. This species lives in a sylvatic environment not far away from the dwellings, and occasionally some individuals are found inside the houses. This study was carried out to describe the biological cycle of T. boliviana and to determine its vectorial competence. The development of a cohort of 95 nymphs of first instar (N1) was followed through nymphal instars and adult stage until death in laboratory (22°C). They were fed twice a week on an immobilized mouse. The median egg-to-adult development time was 8.4 months. The mortality by nymphal instar was lower than 7% except for N1 (67%) and N5 (18%). All nymph instars needed at least two feedings to molt (until six feedings for N5). The differentiation of a nymph into a female or a male could not be detected until the fifth instar for which the food intake was greater for a nymph developing into a female. Adults fed about once a week. The adult life span was around 400 days. The fecundity was 4.2 eggs/female/week, with a hatching rate of 50% and a hatching time of 39 days. In the same conditions, T. infestans showed a similar fecundity but a greater hatching rate and hatching time. A trial for rearing the adults at a higher temperature (26°C) showed a drastic fall in the fecundity and in the hatching rate. The vectorial competence was analyzed for fifth instars and adults by three parameters: the ability to feed on human beings, the capacity to be infected by T. cruzi and the postfeeding defecation delay. Results showed a relatively high vectorial competence: (1) insects fed easily on the tested human being; (2) 100% of the specimens became infected by T. cruzi just by one infected meal; and (3) although the adults defecated after a median postfeeding delay greater than that of T. infestans, results on N5 suggest that they could be as good vectors as T. infestans males.

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This study evaluated the influence of two fruits hosts (orange and papaya) on biological and behavioral parameters of two populations of Ceratitis capitata (Wiedemann) reared under laboratory conditions. One of these populations has been reared under laboratory conditions by 25 years without introduction of wild flies (Lab-pop), while the other has been maintained under the same conditions by 15 years but with occasional introduction of wild specimens (Hybrid-pop). The following parameters were analyzed: emergence percentage, life cycle duration (from eclosion to emergence), adult size, longevity, female fecundity and oviposition preference. The best performance of immatures of both populations was obtained on papaya as a host. Larvae reared on orange had longer life cycle, low emergence percentage and smaller adults. The fruit type did not affect fecundity and longevity of the Lab-pop, but in the Hybrid-pop males lived longer when reared on papaya, while females had higher longevity and fecundity when reared on orange. Females of both populations preferred to lay eggs in papaya (better host for larvae) when compared to orange. However, some eggs were deposited on orange only by females of Lab-pop, suggesting a lower ability for host selection of this population. These data are discussed regarding to the effects of continuous laboratory rearing on the biological parameters of this species.

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ABSTRACT One difficulty in the maintenance of Chrysomya megacephala under laboratory conditions is the rapid putrefaction of the meal used as rearing media. The objective of the present study was to test under controlled conditions two different diets used as laboratory ration: raw fish meal versus an artificial medium containing meat flour, sawdust and water. The diets were tested using 200 larvae in each of three replicates. We observed that larvae reared on fish meal had an average shorter developmental period (8 days); mean adult emergence of 83.3%; mean fertile female weight of 65.185 mg; mean number of eggs per female of 220.722; mean reproductive investment of 3.599; and mean infertility rate of 43.3%. The larvae reared on the other artificial medium had a longer developmental period (10 days); a mean adult emergence of 86%; mean fertile female weight of 64.882; mean number of eggs per female of 218.515; mean reproductive investment of 3.364; and mean infertility rate of 24.4%. We observed that with both diets there was a proportional relation between the number and weight of eggs for each female, and therefore we concluded that diet does in fact influence the fertility of Chrysomya megacephala under laboratory conditions.

RESUMO A dificuldade de manter-seChrysomya megacephala em laboratório está na rápida putrefação dos meios utilizados para sua criação. Para tal, o presente trabalho visou testar sob condições controladas duas dietas: peixe in natura e um meio artificial constituído por farinha de carne, serragem e água. Foram montadas três repetições, para cada dieta, com 200 larvas cada, onde observou-se que o meio constituído por peixe in natura apresentou menor período de desenvolvimento (8 dias), emergência dos adultos de 83,3%, peso médio das fêmeas fecundas de 65,185 mg, média de 220,722 ovos por fêmea, investimento reprodutivo de 3,599 e taxa de infecundidade de 43,3%. O meio artificial apresentou um período maior (10 dias), a emergência dos adultos foi de 86%, o peso médio das fêmeas fecundas foi de 64,882 mg, média de 218,515 ovos por fêmea, investimento reprodutivo de 3,364 e taxa de infecundidade de 24,4%. Verificou-se, em ambas dietas, que houve índice de relação diretamente proporcional entre o peso e o número de ovos por fêmea, concluindo-se que a dieta influi na fecundidade das fêmeas de C. megacephala.

RESUMO

Lutzomyia umbratilis is the main vector of cutaneous leishmaniasis due to Leishmania guyanensis in northern South America. It has been found naturally infected with this species of Leishmania only east of the Rio Negro and north of the Rio Amazonas. However, populations of this sand fly species are also present in areas south of the Amazon river system, which may act as a geographical barrier to the Leishmania guyanensis cycle. With the aim of looking for possible biological differences between populations of L. umbratilis from each side of this river system, their biology in the laboratory was investigated. Progenitors collected on tree bases in Manaus and Manacapuru (east and west, respectively, of the Rio Negro) were reared in the laboratory. Results from observations of the life cycle, fecundity, fertility, and adult longevity at 27ºC and 92% RH were analyzed by descriptive statistics and z, t, U, and chi2 tests. Although the Manaus and Manacapuru colonies showed a longer developmental time than most Lutzomyia species reared at similar temperatures, length of time of egg and 4th instar larva of the two populations differed significantly (p 0.01). Females of the latter retained significantly (p 0.001) less mature oocytes, and the general productivity (% adults from a known number of eggs) of the colony was significantly (p 0.01) higher than that of the former. These results show that the L. umbratilis population of Manaus is more productive, and thus a better candidate for future mass-rearing attempts. The two populations differ in their life cycle, fecundity, fertility, adult longevity, and emergence. These differences may reflect some divergence of intrinsic biological features evolved as a result of their geographical isolation by the Rio Negro. It is expected that further investigations on morphometry, cuticular hydrocarbon, isoenzyme, molecular and chromossomal analyses, infection, and cross-mating experiments with these and other allopatric populations of both margins of the Amazon river system will help reveal whether or not L. umbratilis has genetically diverged into two or more reproductively isolated populations of vectors or non-vectors of Leishmania guyanensis.

Lutzomyia umbratilis é o principal vetor de leishmaniose tegumentar causada por Leishmania guyanensis no norte da América do Sul. Essa espécie tem sido encontrada naturalmente infectada com Leishmania somente ao leste do Rio Negro e norte do Rio Amazonas. Porém, populações dessa espécie de flebotomíneo também estão presentes em áreas do sul do sistema fluvial do Rio Amazonas, o qual pode atuar como uma barreira geográfica no ciclo da Leishmania guyanensis. Com o objetivo de procurar possíveis diferenças biológicas entre populações de L. umbratilis de margens opostas desse sistema fluvial, a biologia de duas populações diferentes foi estudada em laboratório. Progenitores coletados em Manaus e Manacapuru (leste e oeste, respectivamente, do Rio Negro) foram criados separadamente. Resultados de observações do ciclo de vida, fecundidade, fertilidade e longevidade de adultos a 27ºC e 92% UR (umidade relativa) foram analisados por estatística descritiva, e testes z, t, U e chi2. Embora as colônias de Manaus e Manacapuru tenham apresentado desenvolvimento mais demorado que a maioria das espécies de Lutzomyia, a duração das fases de ovo e de larva de 4º estágio nas duas populações foi significativamente (p 0,01) diferente. Fêmeas de Manaus retiveram significativamente (p 0.001) menos óvulos maduros, e a produtividade geral (% de adultos a partir de um número conhecido de ovos) da colônia foi significativamente (p 0,01) mais alta do que a de Manacapuru. Estes resultados apontam a população de L. umbratilis de Manaus como a melhor candidata a futuras tentativas de criação em massa em laboratório. As diferenças observadas nas duas populações quanto ao ciclo de vida, fecundidade, fertilidade, longevidade e emergência de adultos podem ser resultantes do isolamento geográfico ocasionado pelos grandes rios.