RESUMO

Eriopis connexa (Germar) (Coleoptera: Coccinellidae) occurs in several countries of South America and its mass rearing is important for biological control programmes. This work evaluated biological aspects of E. connexa larva fed on eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) and Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) frozen for one day, fresh eggs of Diatraea saccharalis (Fabricius) (Lepidoptera: Pyralidae), S. frugiperda newly-hatched caterpillars, nymphs of Rhopalosiphum maidis (Fitch) and Schizaphis graminum (Rondani) (Hemiptera: Aphididae). Duration of larva, pupa and larva to adult stages differed among prey offered, whereas the prepupa stage was similar. Larva, pupa, prepupa and larva to adult viabilities were equal or major of 87.5% in all prey, except for larva fed on newly-hatched larvae of S. frugiperda. Eriopis connexa has good adaptation to different prey corroborating its polyphagous feeding habit, which evidences the potential of this natural enemy for controlling corn and sorghum pests.

Eriopis connexa (Germar) (Coleoptera: Coccinellidae) ocorre em vários países da América do Sul e sua criação massal é importante para programas de controle biológico. Este trabalho avaliou os aspectos biológicos de larvas de E. connexa alimentadas com ovos de Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) e de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) congelados por um dia, ovos frescos de Diatraea saccharalis (Fabricius) (Lepidoptera: Pyralidae), lagartas de S. frugiperda recém-eclodidas, ninfas de Rhopalosiphum maidis (Fitch) e Schizaphis graminum (Rondani) (Hemiptera: Aphididae). A duração da fase larval, pupal e de larva a adulto diferiu entre as presas oferecidas; entretanto, a fase de pré-pupa foi semelhante. A viabilidade larval, pré-pupal, pupal e de adultos foi maior ou igual a 87,5% em todas as presas, com exceção para larvas alimentadas com lagartas recém-eclodidas de S. frugiperda. Eriopis connexa tem boa adaptação a diferentes presas, corroborando seu hábito alimentar polífago, o que evidencia o potencial desse inimigo natural para o controle de pragas de milho e sorgo.

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RESUMO

New hosts and parasitism notes for the mite Leptus (Acari: Erythraeidae) in Brazil. Larval erythraeid mites are common ectoparasites of harvestmen (Opiliones). Studies describing insects as potential hosts have received little attention. Specimens of an undescribed species of the genus Leptus were collected in association with predatory and phytophagous Heteroptera bugs in a secondary forest in Viçosa, Minas Gerais state, Brazil. New mite-host records and information on seasonality of this mite are presented.

Há novos hospedeiros e notas sobre o parasitismo do ácaro Leptus (Acari: Erythraeidae) no Brasil. As larvas de ácaros da família Erythraeidae são ectoparasitas comuns de opiliões (Opiliones). Estudos de insetos como potenciais hospedeiros de ácaros eritraídeos são escassos. Indivíduos de uma espécie nova do gênero Leptus foram coletados em associação com percevejos fitófagos e predadores (Heteroptera) em uma floresta secundária no município de Viçosa-Minas Gerais, Brasil. São apresentadas informações sobre a sazonalidade e o registro de hospedeiro desse ácaro do gênero Leptus.

Assuntos

RESUMO

New hosts and parasitism notes for the mite Leptus (Acari: Erythraeidae) in Brazil. Larval erythraeid mites are common ectoparasites of harvestmen (Opiliones). Studies describing insects as potential hosts have received little attention. Specimens of an undescribed species of the genus Leptus were collected in association with predatory and phytophagous Heteroptera bugs in a secondary forest in Viçosa, Minas Gerais state, Brazil. New mite-host records and information on seasonality of this mite are presented.

Há novos hospedeiros e notas sobre o parasitismo do ácaro Leptus (Acari: Erythraeidae) no Brasil. As larvas de ácaros da família Erythraeidae são ectoparasitas comuns de opiliões (Opiliones). Estudos de insetos como potenciais hospedeiros de ácaros eritraídeos são escassos. Indivíduos de uma espécie nova do gênero Leptus foram coletados em associação com percevejos fitófagos e predadores (Heteroptera) em uma floresta secundária no município de Viçosa-Minas Gerais, Brasil. São apresentadas informações sobre a sazonalidade e o registro de hospedeiro desse ácaro do gênero Leptus.

RESUMO

In Hymenoptera, midgut changes begin in the last instar. At this stage, the larval epithelial digestive cells degenerate, leaving only the basal membrane and the regenerative cells which will develop into a new epithelium during the pupal stage and in the adult. Epithelium renewal is followed by changes in volume and shape of the midgut. Morphometric analysis of digestive cells and total midgut volume of Melipona quadrifasciata anthidioides (Lepeletier) were conducted to verify whether cell volume increase are sufficient to account for the total midgut volume increase that occurs during metamorphosis. An increase in midgut volume was verified in spite of the scarcity of cell proliferation found during metamorphosis. At the end of metamorphosis, the increase in cell volume was not sufficient to explain the increase in volume of the midgut, indicating that an increase in the number of digestive cells is apparently necessary. Nevertheless, the mechanism by which regenerative cells reconstitute the epithelium during metamorphosis remains unknown.

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Several studies have focused on understanding the biochemistry and morphology of the fat body of the hematophagous mosquito Aedes aegypti (L.) (Diptera: Culicidae). In contrast, few studies, if any, have focused on morphological characters of the fat body in other mosquitoes, especially non-hematophagous taxa such as the culicid Toxorhynchites. Larvae of Toxorhynchites prey upon the larvae of other mosquito species and are used in vector mosquito control. We investigated aspects of the fat body trophocytes, including the morphometric analyses of the lipid droplets, protein granules and nuclei, during Toxorhynchites theobaldi (Dyar & Knab) post-embryonic development. Following the body weight increase from larval stage L2 to L4, the size of lipid droplets within the trophocytes also increase, and are likely the result of lipogenesis. Lipid droplets decrease in size during L4 to the female pupal stage and increase once again during the period from newly-emerged to mature adult females. Protein granules are observed for the first time in female pupae, and their appearance might be related to protein storage during metamorphosis. The size of the nucleus of trophocytes also increases during larval development, followed by a decrease during metamorphosis and an additional increase as adult female ages. In conclusion, the morphology of the fat body of T. theobaldi changes according to the developmental stage. Our study provides for the first time important insights into T. theobaldi fat body development and contributes to understand this species biology.

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RESUMO

The mass rearing of parasitoids represents a fundamental stage for programmes of biological control. The progeny of the parasitoid Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae) were evaluated on previously refrigerated pupae of Bombyx mori L. (Lepidoptera: Bombycidae). Forty-eight to 72 hours-old pupae of B. mori were stored at 10 ºC for five, 10, 15 or 20 days and then exposed to parasitism by P. elaeisis females. This parasitoid showed shorter duration of the life cycle when reared on pupae of B. mori which were previously stored at 10 ºC during 15 days. P. elaeisis parasitized 100% of the pupae of B. mori after storage at 10 ºC during all periods with emergence of this parasitoid from 78 to 100% of these pupae. P. elaeisis had a higher number of progeny per pupa of B. mori stored for 15 days at 10 ºC. Pupae of B. mori can be stored for 15 days at 10 ºC before being used to rear P. elaeisis.

A criação de parasitoides em larga escala representa uma etapa fundamental para programas de controle biológico. A progênie de Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae) foi avaliada em pupas de Bombyx mori L. (Lepidoptera: Bombycidae) armazenadas em baixa temperatura. Pupas de B. mori, com 48 a 72 horas de idade, foram armazenadas a 10 ºC por 5, 10, 15 ou 20 dias e, posteriormente, expostas ao parasitismo por fêmeas de P. elaeisis. A duração do ciclo de vida do parasitoide foi menor em pupas de B. mori armazenadas a 10 ºC durante 15 dias. O parasitismo de P. elaeisis atingiu 100% de pupas de B. mori após armazenamento a 10 ºC em todos os períodos, com emergência de 78 a 100% desse parasitoide. A progênie por pupa de P. elaeisis foi maior quando pupas de B. mori foram armazenadas por 15 dias a 10 ºC. Pupas de B. mori podem ser armazenadas por até 15 dias a 10 ºC e serem utilizadas em criações de P. elaeisis.

RESUMO

ABSTRACT Generalist predators are important for the biological control of pests by feeding on many insect pests, especially those occurring in larger abundance. For this reason, they can maintain their populations in different ecosystems, even during periods of prey shortage, and they are found in outbreaks of Lepidoptera defoliators in eucalyptus plantations. The longevity and reproductive parameters of the predatorBrontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) were studied at 26 ± 2° C, 65 ± 10% relative humidity and 12 hours photophase with Tenebrio molitor L. (Coleoptera: Tenebrionidae) (T1) pupae or with this prey and seedlings of Eucalyptus grandis (T2). The longevity of males and females of this predator were 27.4 ± 4.4 and 39.6 ± 3.4 days and 27.0 ± 4.6 and 34.5 ± 3.1 days, respectively. Females were always heavier than males, with 141.1 and 104.9 mg only with T. molitor and 148.8 and 108.3 mg with this prey and E. grandis seedlings, respectively. The viability and number of eggs/female and the longevity of B. tabidus had higher values in the treatment with T. molitor pupae and seedlings of E. grandis.

RESUMO Predadores generalistas são importantes para o controle biológico de pragas por se alimentarem de muitas espécies de insetos, especialmente daquelas em maior abundância, e por se manterem em diferentes agroecossistemas, mesmo em períodos de escassez de presa, tendo sido registrados em surtos de Lepidoptera desfolhadores em plantações de eucalipto. Foram estudados a longevidade e os parâmetros reprodutivos do predador Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) a 26 ± 2° C, 65 ± 10% de U.R. e fotofase de 12 horas, alimentado com Tenebrio molitor L. (Coleoptera: Tenebrionidae) (T1) ou com esta presa e mudas de Eucalyptus grandis (T2). A longevidade de machos e fêmeas foi de 27,4 ± 4,4 e 39,6 ± 3,4 dias e de 27,0 ± 4,6 e 34,5 ± 3,1 dias, respectivamente. As fêmeas foram sempre mais pesadas que os machos, com 141,1 e 104,9 mg apenas com T. molitor, e 148,8 e 108,3mg com essa presa e mudas de E. grandis, respectivamente. A viabilidade dos ovos, o número de ovos/fêmea e a longevidade de B. tabidus foram maiores no tratamento com essa presa e mudas de E. grandis.