Estimating the relationship of sugarcane borer larvae and crop damage based on adult captures and climate variables

ABSTRACT: Sugarcane borer Diatraea saccharalis (F.) is the primary sugarcane pest in Brazil. To estimate the relationship between larvae in sugarcane stalks and captures of male adults of D. saccharalis, we collected samples weekly: (1) adults with one delta trap with three virgin females and three female pupae and (2) larvae in 120 stalks per plot of 12.6 hectares (355 × 355 m). The study was conducted in two sites with five plots each, in the municipalities of Nova Ponte and Tupaciguara, Minas Gerais State, Brazil, from July 2016 to May 2017. Relationships between (1) males trapped per week and the number of larvae outside of stalks (LOS) were estimated and (2) we evaluated climate variables, namely average temperature, average relative air humidity, hours with relative air humidity below 30 %, rainfall and number of rainy days, and adults and larvae of D. saccharalis. We obtained generalized linear models for LOS in autumn and for larvae inside the stalks (LIS) in spring and autumn and trapped males in both sites. A significant and direct relationship between LIS and males trapped allows predicting larvae density based on captures of males. In addition, plant damage can be estimated based on accumulated captures of males. There was a negative relationship between hours of air humidity < 30 % and larvae outside of stalks. Densities of LIS can be estimated from male captures and by the humidity variables in the trapping week. Nevertheless, the models require validation in the field.

Utilização de resíduos de frutos na produção e composição nutricional da larva de Tenebrio molitor / Use of fruit residues in the production and nutritiona l composition of the larva of Tenebrio Molito larva

Este estudo teve como objetivo avaliar a utilização de resíduos de frutos típicos brasileiros sobre o perfil nutricional da larva de Tenebrio molitor. O delineamento experimental foi o bloco casualizado, onde foram testadas quatro dietas diferentes para o desenvolvimento de larvas do T. molitor. O tratamento controle foi composto de trigo, soja e milho, enquanto os outros três tratamentos consistiram em dietas suplementadas com 50% de subprodutos da extração de macaúba, buriti e cacau. Foram realizados quatro tratamentos com quatro repetições entre maio e junho de 2019. Os dados foram analisados através dos testes ANOVA e Holm-Sidak, onde valores de p<0,05 foram considerados estatisticamente significativos. As larvas de T. molitor completaram seu ciclo de vida em todas as dietas testadas, entretanto, na dieta suplementada com cacau, o desenvolvimento em número de larvas foi reduzido em relação aos outros grupos. A farinha dos animais alimentados com a dieta à base de cacau apresentou um teor de proteínas inferior quando comparada à do ao grupo controle (p<0,001). Dietas à base de buriti, cacau e macaúba apresentaram quantidades maiores de extrato etéreo (p<0,018, <0,012 e <0,003, respectivamente). Concluiu-se que a suplementação de Tenébrios com dietas à base de buriti e macaúba pode ser uma boa estratégia para a melhoria do perfil nutricional da farinha de T. molitor, fornecendo quantidades favoráveis de proteínas e minerais. No tocante ao uso do cacau, estudos futuros para avaliar a presença de componentes alcaloides e seus efeitos diretos na suplementação animal devem ser conduzidos, o que pode representar uma limitação deste estudo.

This study aimed to evaluate the use of typical Brazilian fruit residues on the nutritional profile of the Tenebrio Molitor larva. The experimental design was a randomized block, where four different diets were tested for the development of T. molitor larvae. The control treatment consisted of wheat, soy, and corn, while the other three treatments consisted of diets supplemented with 50% of by-products derived from macauba, buriti, and cocoa extraction. Four treatments were carried out with four repetitions between May and June 2019. The data were analyzed using the ANOVA and Holm-Sidak tests, where p values <0.05 were considered statistically significant. T. molitor larvae completed their life cycle in all tested diets; however, the development in number of larvae in the diet supplemented with cocoa was reduced compared to the other groups. The flour of animals fed with a cocoa-based diet showed had a lower protein level when compared to the control group (p<0.001). Diets based on buriti, cacoa, and macaúba presented higher amounts of ether extract (p<0.018, <0.012, and <0.003, respectively). It is concluded that the supplementation of Tenebrios with diets based on buriti and macaúba can be a good strategy to improve the nutritional profile of T. molitor flour, providing favorable amounts of proteins and minerals. Regarding the use of cocoa, further studies to assess the presence of alkaloids and their direct effects on animal supplementation must be conducted, which may represent a limitation of this study.

Influence of rainfall regime in the Cerrado biome on the maintenance of traps built by Myrmeleon brasiliensis (Navás) (Neuroptera: Myrmeleontidae) larvae and the morphology of adults / Influência do regime de chuvas do bioma Cerrado na manutenção das armadilhas de larvas e na morfologia dos adultos de Myrmeleon brasiliensis (Navás) (Neuroptera: Myrmeleontidae)

Seasonality in the Cerrado biome of Brazil is characterized by a dry season and a rainy season, affecting the availability of water and generating nutritional limitations. Thus, plants and animals have developed adaptive mechanisms in order to survive in this environment. Insects known as antlions (Neuroptera: Myrmeleontidae) occur in areas of the Cerrado and build traps in dry soil to capture prey items. In the rainy season, these insects are unable to forage due to the waterlogged soil. The aim of this study was to investigate the influence of the rainfall regime in the Cerrado on aspects of trap-building behavior, larval development and morphological characteristics of adult antlions. Larvae of the antlion Myrmeleon brasiliensis (Návas, 1914) were observed and collected in an area of the Cerrado biome in the municipality of Aquidauana (MS), Brazil. Observations were performed in the rainy and dry seasons to determine the abundance of traps built by M. brasiliensis larvae. In the laboratory, experiments were performed involving the manipulation of the frequency of simulated rain on the traps. The results revealed that variations in rainfall due to seasonality in the Cerrado affect M. brasiliensis larvae, with greater foraging observed in the dry season. The laboratory experiments demonstrated that differences in the frequency of rains affect the mortality of the larvae, larval development time and the size of the adults. Thus, variations in rainfall patterns can lead to variations in the characteristics of the population structure of M. brasiliensis in areas of the Cerrado biome in Brazil.

No bioma Cerrado a sazonalidade (caracterizada por uma estação seca e outra chuvosa) afeta a disponibilidade de água e produz limitações nutricionais, de maneira que várias plantas e animais desenvolveram mecanismos adaptativos elaborados para sobreviver nesse ambiente. Insetos conhecidos como formiga-leão ocorrem em áreas de Cerrado e constroem suas armadilhas de captura de presas no solo seco. No período chuvoso as larvas ficam impedidas de forragear, dado o encharcamento do solo. Este trabalho tem como objetivo compreender a influência do regime de chuvas do Cerrado em aspectos do comportamento de construção da armadilha, no desenvolvimento das larvas e nas características morfológicas dos adultos. Larvas de formiga-leão Myrmeleon brasiliensis (Návas, 1914) foram observadas e coletadas em uma área de Cerrado no município de Aquidauana (MS), Brasil. Para verificar a abundância das armadilhas das larvas de M. brasiliensis foram realizadas observações no período chuvoso e seco. No laboratório foram realizados experimentos de manipulação da frequência de chuva nas armadilhas de M. brasiliensis. Como resultado foi observado que variações na sazonalidade do Cerrado afetam as larvas de M. brasiliensis, as quais são observadas forrageando em maior abundância na estação seca. Os experimentos de laboratório demonstraram que variações na frequência da chuva podem afetar, a mortalidade das larvas, o tempo de desenvolvimento das mesmas, o tamanho das armadilhas e o tamanho dos adultos. Sendo assim, variações no padrão de incidência de chuvas podem levar a variações nas características da estrutura da população de M. brasiliensis em áreas de Cerrado.

Performance of bullfrog tadpoles (Lithobates catesbeianus) fed balanced diets using alternative energy ingredients containing vegetable mesocarp / Desempenho de girinos de rã-touro (Lithobates catesbeianus) alimentados com dietas balanceadas com ingredientes de energia alternativa utilizando mesocarpo vegetal

The objective of this study was to evaluate the performance and metamorphosis of bullfrog tadpoles (Lithobates catesbeianus) fed balanced diets, wherein corn flour was replaced with banana, avocado, and pumpkin meal (all made without the epicarp). Using a completely randomized design, the animals were stored in tanks with a capacity of 30 L in a water recirculation system at a density of 1 tadpole/L. Through biweekly biometric measurements, the weight, standard, and total length were evaluated to determine metamorphic development, weight gain, consumption, feed conversion, specific growth rate, survival, physical-chemical parameters of water, and the percentage carcass composition (only at the end). Tadpoles fed rations balanced with pumpkin and banana flour performed the best, followed by those fed avocado meal and those fed the control ration (p < 0.05). It can be concluded that growth performance is improved in animals fed diets containing 10% pumpkin and banana meal instead of corn, and tadpoles that received the avocado meal had the same performance as the conventional diets. Research should be carried out to assess other avenues for the replacement of ingredients in rations for bullfrog tadpoles.(AU)

O objetivo deste trabalho foi avaliar o desempenho e a metamorfose de girinos de rãtouro (Lithobates catesbeianus) alimentados com dietas balanceadas com farinha de banana, abacate e abóbora, todas feitas sem epicarpo, em substituição à farinha de milho. Utilizando um delineamento inteiramente casualizado, os animais foram colocados em tanques com capacidade de 30 litros em sistema de recirculação de água com densidade de 1 girino / L. Por meio de biometria quinzenal foram avaliados peso, comprimento padrão e total, quanto ao desenvolvimento metamórfico, ganho em peso, consumo, conversão alimentar, taxa de crescimento específico, sobrevivência, parâmetros físico-químicos da água e composição centesimal da carcaça (somente no final). Os resultados mostraram melhor desempenho para girinos alimentados com ração balanceada com farinha de abóbora e banana, seguidos daqueles alimentados com farelo de abacate e alimentados com ração controle (p <0,05). Os animais alimentados com as duas últimas rações não diferiram (p> 0,05). Pode-se concluir que houve melhor desempenho nos animais alimentados com dietas contendo 10% de abóbora e farelo de banana ao invés de milho, e aqueles que receberam farelo de abacate com o mesmo desempenho das dietas tradicionais. Pesquisas devem ser realizadas para avaliar outros níveis de reposição desses nutrientes por girinos de rã-touro.(AU)

First record of Plectris aliena Chapin, 1934 (Coleoptera: Melolonthidae) as a potential sugarcane pest in Brazil

Plectris aliena Chapin, 1934, a white grub that promotes serious damage to a variety of crops in North America and Australia, has been reported for the first time in Brazil. Larvae and adults of P. aliena were recorded in sugarcane crops in the state of Mato Grosso do Sul, sampled by trenches in the soil with light traps, respectively, during 2012 and 2013. Root consumption was also determined for the first, second and third instar larvae. The species is univoltine; adults were found mainly in Aug and the peak of third instar larval density was in Apr in all fields sampled. Pupae and adults of P. aliena were observed in the soil profile at depths of up to 60 and 80 cm, respectively. Larvae of P. aliena of the second and third instar consumed the primary and secondary roots of sugarcane, causing serious damage. Third instar larvae consumed 916 mg of root fresh matter, representing 72 % of the sugarcane root system. These results assist in furthering the understanding of its larval dynamics in the soil and provide support for Integrated Pest Management.

Prevalência de Oestrus ovis (Diptera: Oestridae) em ovinos de Ituiutaba, região sudeste do Brasil / Prevalence of Oestrus ovis (Diptera: Oestridae) in sheep from Ituiutaba, southeast region of Brazil

Dentre as doenças que podem atingir as cavidades nasais dos pequenos ruminantes, destaca-se a oestrose. No Brasil, mais especificamente na região Sudeste, os relatos estão limitados ao estado de São Paulo e ao município de Araxá, Minas Gerais. Assim, procurou-se avaliar a prevalência parasitária do Oestrus ovis em ovinos criados no município de Ituiutaba, Minas Gerais-Brasil, correlacionando ao mesmo tempo o tamanho e estágio larval com a sua localização anatômica. Oitenta e oito hemicabeças de Ovis aries mestiços Santa Inês com Dorper saudáveis foram utilizadas aleatoriamente. As larvas visualizadas foram então coletadas e fixadas para serem quantificadas e analisadas em relação ao seu tamanho e estágio de desenvolvimento. Conclui-se que a oestrose é um problema existente no município de Ituiutaba, sendo este o primeiro estudo completo sobre a prevalência deste parasito no estado de Minas Gerais. Por distribuição anatômica, apenas as diferenças das médias larvais totais entre o seio frontal e o meato nasal ventral, meato nasal comum e a nasofaringe foram significativas - o que confirma a preferência das larvas por essa região. Em tamanho, a diferença significativa só ocorreu mediante a comparação entre o tamanho e estágio das larvas, informação crucial para uma melhor compreensão da progressão cíclica, sintomatologia clínica e profilaxia dos animais.

Among the diseases which can afflict the nasal cavities of small ruminants, oestrosis stands out. In Brazil, more specifically in its South-East region, the reports are limited only to the State of São Paulo and to the municipality of Araxá, Minas Gerais. Therefore, it has been sought to assess the parasitic prevalence of Oestrus ovis in sheep farmed in the municipality of Ituiutaba, Minas Gerais-Brazil, while correlating the larval size and stage, and its anatomical localization. Eighty-eight hemiheads of healthy Santa Inês/Dorper crossbreds Ovis aries have been used at random. The larvae in view were then collected and fixated to be quantified and analyzed in regard of size and stage of development. It is concluded that the oestrosis is an existing problem in the municipality of Ituiutaba, this being the first complete study on the prevalence of this parasite in the State of Minas Gerais. By anatomical distribution, only the differences of total larval averages between the frontal sinus and the ventral nasal meatus, the common nasal meatus and the nasopharynx have been significant. In size, the significant difference has been there only upon comparison between the size and the larval stage, information that is crucial for a better understanding of the cyclic progression, of the clinical symptomatology, and animal prophylaxis.

Toxic effects of Drimia maritima (Asparagaceae) ethanolic extracts on the mortality, development, sexual behaviour and oviposition behaviour of Drosophila melanogaster (Diptera: Drosophilidae)

Drimia maritima is a toxic Mediterranean plant and is considered a commercially important drug by its medicinal values and pharmacological properties. In this work, we seek to evaluate the direct and delayed effects of the ethanol extracts of this plant on vinegar fly (Drosophila melanogaster), an excellent laboratory model. The treatment was carried out by ingestion on second-stage larvae (L2) and then we evaluated the impact of this treatment on mortality, development, sexual behaviour, on female's oviposition choice, fecundity, and fertility of adults. The results showed that mortality rates can reach 100% after 15 days of treatment as we recorded an acceleration of the flies' development. After treatment, we observed incomplete nuptial courtship and a significant decrease in eggs laid number and larvae number of the first generation treated. This study indicates that D. maritima ethanolic extract has a neurotoxic property, our results confirmed the presence of toxic secondary metabolites in the extract studied.(AU)

Toxic effects of Drimia maritima (Asparagaceae) ethanolic extracts on the mortality, development, sexual behaviour and oviposition behaviour of Drosophila melanogaster (Diptera: Drosophilidae)

Drimia maritima is a toxic Mediterranean plant and is considered a commercially important drug by its medicinal values and pharmacological properties. In this work, we seek to evaluate the direct and delayed effects of the ethanol extracts of this plant on vinegar fly (Drosophila melanogaster), an excellent laboratory model. The treatment was carried out by ingestion on second-stage larvae (L2) and then we evaluated the impact of this treatment on mortality, development, sexual behaviour, on female's oviposition choice, fecundity, and fertility of adults. The results showed that mortality rates can reach 100% after 15 days of treatment as we recorded an acceleration of the flies' development. After treatment, we observed incomplete nuptial courtship and a significant decrease in eggs laid number and larvae number of the first generation treated. This study indicates that D. maritima ethanolic extract has a neurotoxic property, our results confirmed the presence of toxic secondary metabolites in the extract studied.

Description of the late- or last-instar larva of Ischyomius Chevrolat, with comments on the family placement of the genus (Coleoptera: Tenebrionoidea: Pythidae)

Study of recently collected larvae of two species of Ischyomius Chevrolat, 1871 from Napo and Pichincha, Ecuador, tentatively identified as I. denticollis Champion, 1916 and I. singularis Chevrolat, 1871 confirm the classification of the genus Ischyomius within the family Pythidae. Salient larval characters which solidify this placement are: 5 stemmata arranged into an anterior column of 3 and posterior column of 2, parabasal ridges along anterior margins of abdominal tergites, prominent urogomphi with inner urogomphal teeth and various dorsal tubercles, and transverse row of dentiform asperities along anterior margin of sternite 9. Important features of the larva are illustrated with photographs. A key to larvae of world genera of Pythidae is provided as well as natural history information on Ischyomius.(AU)

Description of the late- or last-instar larva of Ischyomius Chevrolat, with comments on the family placement of the genus (Coleoptera: Tenebrionoidea: Pythidae)

Study of recently collected larvae of two species of Ischyomius Chevrolat, 1871 from Napo and Pichincha, Ecuador, tentatively identified as I. denticollis Champion, 1916 and I. singularis Chevrolat, 1871 confirm the classification of the genus Ischyomius within the family Pythidae. Salient larval characters which solidify this placement are: 5 stemmata arranged into an anterior column of 3 and posterior column of 2, parabasal ridges along anterior margins of abdominal tergites, prominent urogomphi with inner urogomphal teeth and various dorsal tubercles, and transverse row of dentiform asperities along anterior margin of sternite 9. Important features of the larva are illustrated with photographs. A key to larvae of world genera of Pythidae is provided as well as natural history information on Ischyomius.

Oviposition preference and biological performance of Ceratitis capitata in Anacardiaceae, Cactaceae and Vitaceae fruit / Preferência de oviposição e performance biológica de Ceratitis capitata em frutos de Anacardiaceae, Cactaceae e Vitaceae

The objective of this study was to compare the use of fruits of great economic and social importance for the northeast of Brazil by Ceratitis capitata Wied. (Diptera: Tephritidae) for oviposition, larval development, size and longevity of adults. Fruits of mango (Mangifera indica L.), quiabento (Pereskia bahiensis Gürke), forage palm [Opuntia fícus indica (L.) Mill] and grape (Vitis vinifera L.) were used, as well as flies from a hybrid laboratory population. Initially, four treatments (fruits) and six replications were used; the fruits were offered to 10 C. capitata couples, with later (96 hours) egg count. The second was conducted with six treatments and 10 replicates, offering two types of fruits simultaneously, combined two to two, to 10 C. capitata couples. The last bioassay comprised four treatments and six replicates, where 20 g of fruit were offered to 20 first-instar C. capitata larvae. After six days, the larvae were placed in plastic pots containing vermiculite until pupation, quantifying larval and pupal periods, viability and pupal mass, besides longevity and adult size. The data were submitted to ANOVA using the R Core Team software. Ceratitis capitata oviposits and completes its biological cycle in the four hosts studied, exhibiting no preference for oviposition and low biological performance in quiabento fruits. It yielded smaller adults and lower grape survival. Cactaceae palm and quiabento allow the survival of C. capitata in the laboratory, and this knowledge has been reported for the first time, proving that they can act as alternative hosts in the field.(AU)

O objetivo do estudo foi comparar a utilização de frutos de importância econômica e social para o nordeste do Brasil por Ceratitis capitata Wied. (Diptera: Tephritidae) para oviposição, desenvolvimento larval, tamanho e longevidade de adultos. Foram utilizados frutos de manga (Mangifera indica L.), quiabento (Pereskia bahiensis Gürke), palma-forrageira [Opuntia fícus indica (L.) Mill] e uva (Vitis vinifera L.) e moscas procedentes de uma população híbrida de laboratório. Inicialmente, utilizaram-se quatro tratamentos (frutos) e seis repetições, com o oferecimento dos frutos a 10 casais de C. capitata, com posterior (96 horas) contagem de ovos. O segundo teste foi conduzido com seis tratamentos e 10 repetições, oferecendo-se dois tipos de frutos simultaneamente, combinados dois a dois, a 10 casais de C. capitata. O último bioensaio compreendeu quatro tratamentos e seis repetições, sendo oferecidos 20 g de fruto a 20 larvas de primeiro instar de C. capitata. Após seis dias, as larvas foram colocadas em potes plásticos contendo vermiculita até a empupação, quantificando-se: períodos larval e pupal, viabilidade e massa pupal e longevidade e tamanho do adulto. Os dados foram submetidos à análise de variância (ANOVA) pelo Programa R Core Team. Ceratitis capitata oviposita e completa seu ciclo biológico nos quatro hospedeiros estudados, exibindo não preferência para oviposição e baixa performance biológica em frutos de quiabento. Este proporcionou adultos menores e a uva permitiu a menor sobrevivência. As cactáceas palma e quiabento permitem a sobrevivência de C. capitata em laboratório, sendo esse conhecimento relatado pela primeira vez, comprovando que essas espécies podem atuar como hospedeiros alternativos no campo.(AU)

Oviposition preference and biological performance of Ceratitis capitata in Anacardiaceae, Cactaceae and Vitaceae fruit / Preferência de oviposição e performance biológica de Ceratitis capitata em frutos de Anacardiaceae, Cactaceae e Vitaceae

The objective of this study was to compare the use of fruits of great economic and social importance for the northeast of Brazil by Ceratitis capitata Wied. (Diptera: Tephritidae) for oviposition, larval development, size and longevity of adults. Fruits of mango (Mangifera indica L.), quiabento (Pereskia bahiensis Gürke), forage palm [Opuntia fícus indica (L.) Mill] and grape (Vitis vinifera L.) were used, as well as flies from a hybrid laboratory population. Initially, four treatments (fruits) and six replications were used; the fruits were offered to 10 C. capitata couples, with later (96 hours) egg count. The second was conducted with six treatments and 10 replicates, offering two types of fruits simultaneously, combined two to two, to 10 C. capitata couples. The last bioassay comprised four treatments and six replicates, where 20 g of fruit were offered to 20 first-instar C. capitata larvae. After six days, the larvae were placed in plastic pots containing vermiculite until pupation, quantifying larval and pupal periods, viability and pupal mass, besides longevity and adult size. The data were submitted to ANOVA using the R Core Team software. Ceratitis capitata oviposits and completes its biological cycle in the four hosts studied, exhibiting no preference for oviposition and low biological performance in quiabento fruits. It yielded smaller adults and lower grape survival. Cactaceae palm and quiabento allow the survival of C. capitata in the laboratory, and this knowledge has been reported for the first time, proving that they can act as alternative hosts in the field.(AU)

O objetivo do estudo foi comparar a utilização de frutos de importância econômica e social para o nordeste do Brasil por Ceratitis capitata Wied. (Diptera: Tephritidae) para oviposição, desenvolvimento larval, tamanho e longevidade de adultos. Foram utilizados frutos de manga (Mangifera indica L.), quiabento (Pereskia bahiensis Gürke), palma-forrageira [Opuntia fícus indica (L.) Mill] e uva (Vitis vinifera L.) e moscas procedentes de uma população híbrida de laboratório. Inicialmente, utilizaram-se quatro tratamentos (frutos) e seis repetições, com o oferecimento dos frutos a 10 casais de C. capitata, com posterior (96 horas) contagem de ovos. O segundo teste foi conduzido com seis tratamentos e 10 repetições, oferecendo-se dois tipos de frutos simultaneamente, combinados dois a dois, a 10 casais de C. capitata. O último bioensaio compreendeu quatro tratamentos e seis repetições, sendo oferecidos 20 g de fruto a 20 larvas de primeiro instar de C. capitata. Após seis dias, as larvas foram colocadas em potes plásticos contendo vermiculita até a empupação, quantificando-se: períodos larval e pupal, viabilidade e massa pupal e longevidade e tamanho do adulto. Os dados foram submetidos à análise de variância (ANOVA) pelo Programa R Core Team. Ceratitis capitata oviposita e completa seu ciclo biológico nos quatro hospedeiros estudados, exibindo não preferência para oviposição e baixa performance biológica em frutos de quiabento. Este proporcionou adultos menores e a uva permitiu a menor sobrevivência. As cactáceas palma e quiabento permitem a sobrevivência de C. capitata em laboratório, sendo esse conhecimento relatado pela primeira vez, comprovando que essas espécies podem atuar como hospedeiros alternativos no campo.(AU)

Growth performance and incidence of skeletal anomalies in pacu larvae under different weaning protocols / Desempenho e incidência de anomalias esqueléticas em larvas de pacu sob diferentes protocolos de transição alimentar

The inadequate supply of food during a fishs larval stage, in addition to impairing growth and survival, may lead to the emergence of skeletal anomalies, since essential nutrients are involved in the osteogenic process. The aim of this study was to evaluate the effects of two weaning periods on growth, survival and incidence of skeletal anomalies in pacu larvae (Piaractus mesopotamicus) during its initial development. The larvae (5 dph) were placed in 100L tanks at a density of 12 larvae L-1, during 42 days. The experiment was conducted in a completely randomized design with four feeding treatments: (A) larvae fed only Artemia nauplii; (D) larvae fed only formulated diet; and two treatments with different weaning periods, early at six (W6) and late, at twelve days of feeding (W12). Higher growth indexes and survival rates were observed in A and W12, in comparison to W6 and D. At the end of the experiment, larvae fed Artemia nauplii and subjected to late weaning (W12) presented higher mass gain and survival, in comparison to W6 and D, however the incidence of skeletal anomalies was similar among treatments. It was concluded that the emergence of skeletal anomalies in P. mesopotamicus larvae was not associated to the weaning protocols used in this study and late weaning, at 12 days of feeding, did not impair growth and survival of these larvae.(AU)

A oferta inadequada do alimento durante a fase larval dos peixes, além de prejudicar o crescimento e a sobrevivência, podem causar anomalias esqueléticas, uma vez que nutrientes essenciais estão envolvidos na osteogênese. O objetivo deste estudo foi avaliar os efeitos de dois períodos de transição alimentar no crescimento, sobrevivência e na incidência de anomalias esqueléticas em larvas de pacu (Piaractus mesopotamicus) durante seu desenvolvimento inicial. Larvas com 5 dias pós-eclosão (dph) foram acondicionadas em tanques (100L), em uma densidade de 12 larvas L-1, durante 42 dias. O experimento foi conduzido em delineamento inteiramente casualizado e apresentou quatro tratamentos alimentares: (A) larvas alimentadas apenas com náuplios de artêmia; (D) larvas alimentadas apenas com dieta formulada; e dois tratamentos com diferentes períodos de início da transição entre alimento vivo e formulado, (W6) prematuro, aos seis dias de alimentação, e (W12) tardio, aos 12 dias de alimentação. Ao final do experimento, as larvas dos tratamentos A e W12 apresentaram médias de ganho em massa e sobrevivência maiores que as dos tratamentos W6 e D, no entanto a incidência de anomalias esqueléticas foi similar entre os tratamentos. Foi possível concluir que incidência de anomalias esqueléticas em larvas de P. mesopotamicus não foi associada aos protocolos de transição alimentar adotados nesse estudo e a transição alimentar tardia, aos 12 dias de alimentação, pode ser realizada sem comprometer o crescimento e sobrevivência das larvas.(AU)

Growth performance and incidence of skeletal anomalies in pacu larvae under different weaning protocols / Desempenho e incidência de anomalias esqueléticas em larvas de pacu sob diferentes protocolos de transição alimentar

The inadequate supply of food during a fish’s larval stage, in addition to impairing growth and survival, may lead to the emergence of skeletal anomalies, since essential nutrients are involved in the osteogenic process. The aim of this study was to evaluate the effects of two weaning periods on growth, survival and incidence of skeletal anomalies in pacu larvae (Piaractus mesopotamicus) during its initial development. The larvae (5 dph) were placed in 100L tanks at a density of 12 larvae L-1, during 42 days. The experiment was conducted in a completely randomized design with four feeding treatments: (A) larvae fed only Artemia nauplii; (D) larvae fed only formulated diet; and two treatments with different weaning periods, early at six (W6) and late, at twelve days of feeding (W12). Higher growth indexes and survival rates were observed in A and W12, in comparison to W6 and D. At the end of the experiment, larvae fed Artemia nauplii and subjected to late weaning (W12) presented higher mass gain and survival, in comparison to W6 and D, however the incidence of skeletal anomalies was similar among treatments. It was concluded that the emergence of skeletal anomalies in P. mesopotamicus larvae was not associated to the weaning protocols used in this study and late weaning, at 12 days of feeding, did not impair growth and survival of these larvae.

A oferta inadequada do alimento durante a fase larval dos peixes, além de prejudicar o crescimento e a sobrevivência, podem causar anomalias esqueléticas, uma vez que nutrientes essenciais estão envolvidos na osteogênese. O objetivo deste estudo foi avaliar os efeitos de dois períodos de transição alimentar no crescimento, sobrevivência e na incidência de anomalias esqueléticas em larvas de pacu (Piaractus mesopotamicus) durante seu desenvolvimento inicial. Larvas com 5 dias pós-eclosão (dph) foram acondicionadas em tanques (100L), em uma densidade de 12 larvas L-1, durante 42 dias. O experimento foi conduzido em delineamento inteiramente casualizado e apresentou quatro tratamentos alimentares: (A) larvas alimentadas apenas com náuplios de artêmia; (D) larvas alimentadas apenas com dieta formulada; e dois tratamentos com diferentes períodos de início da transição entre alimento vivo e formulado, (W6) prematuro, aos seis dias de alimentação, e (W12) tardio, aos 12 dias de alimentação. Ao final do experimento, as larvas dos tratamentos A e W12 apresentaram médias de ganho em massa e sobrevivência maiores que as dos tratamentos W6 e D, no entanto a incidência de anomalias esqueléticas foi similar entre os tratamentos. Foi possível concluir que incidência de anomalias esqueléticas em larvas de P. mesopotamicus não foi associada aos protocolos de transição alimentar adotados nesse estudo e a transição alimentar tardia, aos 12 dias de alimentação, pode ser realizada sem comprometer o crescimento e sobrevivência das larvas.

Effect of asymmetric competition on distance among Myrmeleon brasiliensis (Návas, 1914) (Neuroptera: Myrmeleontidae) larvae

In cases of asymmetric competition, larger individuals of many animal species have a greater probability of acquiring territory, gaining initial access to resources and finding a mate in comparison to smaller individuals. The competition among larvae of the antlion Myrmeleon brasiliensis (Neuroptera, Myrmeleontidae) is observed in the search for space for the construction of traps, in the forage for prey, and in the occurrence of cannibalism. The body size of the larvae is proportional to the size of the traps and the success of predation. Thus, larger specimens are better competitors in terms of capturing preys (asymmetric competition). The aim of the present study was to determine the effects of asymmetric competition in M. brasiliensis regarding the distance among these larvae. The study was developed in a permanent reserve area, located in the municipality of Aquidauana, from the Mato Grosso do Sul state, Brazil. For the laboratory experiments, we collected M. brasiliensis larvae and placed two larvae in plastic pots. The observations occurred by the visual search of traps, when a larva was seen in the diameter of its trap and the trap of its closest neighbor. Next, the trap size and the distance between them were measured for a period of 15 days. The results of the present study demonstrate that the largest M. brasiliensis larvae were outside the clusters. Within these clusters, the larvae moved away from each other because of the size of their traps, as the larger the neighboring larvae the greater the distance between them. Thus, the asymmetric competition between M. brasiliensis (larger larvae are better competitors) suggests a spatial arrangement among the larvae that is guided by the variable size of the trap.

Effect of asymmetric competition on distance among Myrmeleon brasiliensis (Návas, 1914) (Neuroptera: Myrmeleontidae) larvae

In cases of asymmetric competition, larger individuals of many animal species have a greater probability of acquiring territory, gaining initial access to resources and finding a mate in comparison to smaller individuals. The competition among larvae of the antlion Myrmeleon brasiliensis (Neuroptera, Myrmeleontidae) is observed in the search for space for the construction of traps, in the forage for prey, and in the occurrence of cannibalism. The body size of the larvae is proportional to the size of the traps and the success of predation. Thus, larger specimens are better competitors in terms of capturing preys (asymmetric competition). The aim of the present study was to determine the effects of asymmetric competition in M. brasiliensis regarding the distance among these larvae. The study was developed in a permanent reserve area, located in the municipality of Aquidauana, from the Mato Grosso do Sul state, Brazil. For the laboratory experiments, we collected M. brasiliensis larvae and placed two larvae in plastic pots. The observations occurred by the visual search of traps, when a larva was seen in the diameter of its trap and the trap of its closest neighbor. Next, the trap size and the distance between them were measured for a period of 15 days. The results of the present study demonstrate that the largest M. brasiliensis larvae were outside the clusters. Within these clusters, the larvae moved away from each other because of the size of their traps, as the larger the neighboring larvae the greater the distance between them. Thus, the asymmetric competition between M. brasiliensis (larger larvae are better competitors) suggests a spatial arrangement among the larvae that is guided by the variable size of the trap.(AU)

Estratégias alimentares na larvicultura do peixe ornamental amazônico acará-severo (Heros severus) (Heckel, 1840) / Feeding strategies on larval rearing of severum (Heros severus) (Heckel, 1840), Amazonian ornamental fish

Com o presente estudo, objetivou-se avaliar o tempo de fornecimento de náuplios de artêmia e o período de transição alimentar para pós-larvas de acará-severo (Heros severus). Foram utilizadas 450 pós-larvas de acará-severo, distribuídas em 45 aquários, em delineamento inteiramente ao acaso, em esquema fatorial 3x5, com três repetições. Foram avaliados três períodos de fornecimento de náuplios de artêmia: zero, cinco e 10 dias. Além disso, foram testados cinco períodos de transição alimentar: um, dois, três, quatro e cinco dias, quando os animais receberam alimentação conjunta de náuplios de artêmia e dieta farelada. Ao final do experimento, os peixes foram contados, pesados e fotografados, para avaliação do desempenho produtivo e das variáveis morfométricas. Para todos os parâmetros avaliados, não foi constatada interação entre o tempo de fornecimento de artêmia e o período de transição alimentar. Os animais alimentados por 10 dias com náuplios de artêmia apresentaram os melhores resultados de desempenho e as maiores variáveis morfométricas. Os peixes que receberam alimentação conjunta por três dias apresentaram desenvolvimento satisfatório. Dessa forma, recomendam-se 10 dias de fornecimento de náuplios de artêmia e três dias de transição alimentar, antes de se iniciar o fornecimento exclusivo de dieta inerte para pós-larvas de acará-severo.(AU)

The aim of this study was to evaluate the supply time of artemia and the period of food transition to post-larvae of severum (Heros severus). A total of 450 post-larvae of severum were distributed in 45 aquaria, in a completely randomized design, in a 3x5 factorial scheme, with three replicates. Three feeding periods with artemia nauplii were evaluated: zero, five, and ten days. In addition, five feeding transitions were tested: one, two, three, four and five days, when the animals received joint feeding of artemia nauplii and dry diet. At the end of the experiment the fish were counted, weighed and photographed, to evaluate the productive performance and the morphometric variables. For all parameters evaluated, no interaction between the time of artemia supply and the feeding transition period was observed. Animals fed for 10 days with artemia nauplii showed the best performance results and the highest morphometric variables. The fish that received joint feeding for three days presented satisfactory development. Thus, 10 days of artemia nauplii supply and three days of feeding transition is recommended before starting the exclusive supply of diet inert to post-larvae of severum.(AU)

Estratégias alimentares na larvicultura do peixe ornamental amazônico acará-severo (Heros severus) (Heckel, 1840) / Feeding strategies on larval rearing of severum (Heros severus) (Heckel, 1840), Amazonian ornamental fish

Com o presente estudo, objetivou-se avaliar o tempo de fornecimento de náuplios de artêmia e o período de transição alimentar para pós-larvas de acará-severo (Heros severus). Foram utilizadas 450 pós-larvas de acará-severo, distribuídas em 45 aquários, em delineamento inteiramente ao acaso, em esquema fatorial 3x5, com três repetições. Foram avaliados três períodos de fornecimento de náuplios de artêmia: zero, cinco e 10 dias. Além disso, foram testados cinco períodos de transição alimentar: um, dois, três, quatro e cinco dias, quando os animais receberam alimentação conjunta de náuplios de artêmia e dieta farelada. Ao final do experimento, os peixes foram contados, pesados e fotografados, para avaliação do desempenho produtivo e das variáveis morfométricas. Para todos os parâmetros avaliados, não foi constatada interação entre o tempo de fornecimento de artêmia e o período de transição alimentar. Os animais alimentados por 10 dias com náuplios de artêmia apresentaram os melhores resultados de desempenho e as maiores variáveis morfométricas. Os peixes que receberam alimentação conjunta por três dias apresentaram desenvolvimento satisfatório. Dessa forma, recomendam-se 10 dias de fornecimento de náuplios de artêmia e três dias de transição alimentar, antes de se iniciar o fornecimento exclusivo de dieta inerte para pós-larvas de acará-severo.(AU)

The aim of this study was to evaluate the supply time of artemia and the period of food transition to post-larvae of severum (Heros severus). A total of 450 post-larvae of severum were distributed in 45 aquaria, in a completely randomized design, in a 3x5 factorial scheme, with three replicates. Three feeding periods with artemia nauplii were evaluated: zero, five, and ten days. In addition, five feeding transitions were tested: one, two, three, four and five days, when the animals received joint feeding of artemia nauplii and dry diet. At the end of the experiment the fish were counted, weighed and photographed, to evaluate the productive performance and the morphometric variables. For all parameters evaluated, no interaction between the time of artemia supply and the feeding transition period was observed. Animals fed for 10 days with artemia nauplii showed the best performance results and the highest morphometric variables. The fish that received joint feeding for three days presented satisfactory development. Thus, 10 days of artemia nauplii supply and three days of feeding transition is recommended before starting the exclusive supply of diet inert to post-larvae of severum.(AU)

Evaluation of survival and metamorphosis of larvae of Caligus rogercresseyi (Boxshall and Bravo, 2000) (Crustacea, Copepoda) in Chile, depending on temperature, salinity and oxygen / Avaliação de sobrevivência e metamorfose de larvas de Caligus rogercresseyi (Boxshall and Bravo, 2000) (Crustacea, Copepoda) no Chile, dependendo da temperatura, salinidade e oxigênio

The present study assessed the percentage of survival and metamorphosis of larval stages of Caligus rogercresseyi (Boxshall and Bravo, 2000) nauplius I, nauplius II to and nauplius II to copepodite, conducting bioassays in triplicate with 50 larvae each, nauplius I or nauplius II, at temperature of 12 °C, 15 °C and 18 °C; salinity 20, 23, 25, 2729, 31, 33 and 35 g/L and oxygen saturation with ranges between 30-60%, 90-100% and 190 - 200%. Bioassays were performed in station Quillaipe of Fundación Chile, Puerto Montt, Chile. It is concluded that the temperature is inversely proportional to the time of metamorphosis and survival of the larvae of Caligus rogercresseyi . In salinity is observed that increased this, greater is the percentage of survival and metamorphosis is faster, while the larvae do not survive less than 20g/L. Oxygen saturation ranges indicate that the larvae do not survive at saturations between 30-60%, and it had no differences between 90-100% saturation and 190-200%.(AU)

O presente estudo avaliou a percentagem de sobrevivência e metamorfose dos estádios larvais de Caligus rogercresseyi (Boxshall and Bravo, 2000) nauplio I, nauplio II ae nauplio II a copepodita, realizando bioensaios em triplicado com 50 larvas cada, nauplio I ou nauplio II, À temperatura de 12 °C, 15 °C e 18 °C; Salinidade 20, 23, 25, 2729, 31, 33 e 35 g / L e saturação de oxigénio com variações entre 30-60%, 90-100% e 190-200%. Os bioensaios foram realizados na estação Quillaipe da Fundação Chile, Puerto Montt, Chile. Conclui - se que a temperatura é inversamente proporcional ao tempo de metamorfose e sobrevivência das larvas de Caligus rogercresseyi. Na salinidade observa-se que aumentou esta, maior é a percentagem de sobrevivência e metamorfose é mais rápida, enquanto as larvas não sobrevivem menos de 20g / L. Os intervalos de saturação de oxigénio indicam que as larvas não sobrevivem a saturações entre 30-60% e não têm diferenças entre 90-100% de saturação e 190-200%.(AU)

Duration of co-feeding on the Nishikigoi Cyprinus carpio larvae during weaning from live to inert food in an indoor system / Período de co-alimentação na transição alimentar de larvas de Nishikigoi Cyprinus carpio em sistema “in door”

This study aimed to evaluate the effects of the co-feeding period (C) on the survival and growth of larvae of nishikigoi Cyprinus carpio, during the weaning period from live to inert food. A total of 1680 larvae with initial weight of 1.33 ± 0.12mg and initial length of 6.0 ± 0.33mm were used. The inert diet used was a commercial ration with 55% crude protein and the live food was the newly hatched nauplii of Artemia franciscana. The experiment was conducted following a completely randomized design with six treatments and four replications. Treatments constituted of: a) LF = supply of live food throughout the experimental period; b) C4 = 6 days of live food + 4 days of co-feeding (inert diet and live food) + 16 days of inert diet; c) C8 = 6 days of live food + 8 days of co-feeding + 12 days of inert diet; d) C12 = 6 days of live food + 12 days of co-feeding + 8 days of inert diet; e) IF = supply with inert diet throughout the experimental period; and f) F = fasting. Our results showed that the co-feeding period influences the survival and growth of the larvae. Survival in the treatment with the longest co-feeding period showed an improvement of over 70% when compared to the shortest period. Further, we noted a doubling of the juvenile weight after 26 days of age. There was a quadratic effect for all parameters, with maximum points ranging between 19.4 and 22.6 days of supply of live food. We concluded that the supply of commercial feed as exclusive food is unworkable in nishikigoi larviculture.(AU)

Com o objetivo de avaliar os efeitos do período de co-alimentação (C) na sobrevivência e crescimento de larvas de nishikigoi Cyprinus carpio, durante o período de transição de alimentos vivos (AV) para dieta inerte (DI), foram utilizados um total de 1680 larvas com peso inicial de 1,33 ± 0,12mg e comprimento inicial de 6,0 ± 0,33mm. Para a dieta inerte foi utilizada uma ração comercial com 55% de proteína bruta e como alimento vivo, nauplios recém eclodidos de Artemia franciscana. O experimento foi conduzido em delineamento inteiramente casualizado com seis tratamentos e quatro repetições. Os tratamentos foram constituídos por: LF = suprimento de alimento vivo ao longo de todo período experimental; C4 = 6 dias de alimento vivo + 4 dias de co-alimentação (dieta inerte e alimento vivo) + 16 dias de dieta inerte; C8 = 6 dias de alimento vivo + 8 dias de co-alimentação + 12 dias de dieta inerte; C12 = 6 dias de alimento vivo + 12 dias de co-alimentação + 8 dias de dieta inerte; ID = dieta inerte durante todo o período experimental, J = jejum. O período de co-alimentação influencia a sobrevivência e o crescimento das larvas melhorando mais de 70% a sobrevida entre os períodos de co-alimentação mais longos e curtos testados. Além disso, foi verificado um aumento de duas vezes o peso juvenil após 26 dias de idade. Houve um efeito quadrático para todos os parâmetros, com pontos máximos variando entre 19,4 e 22,6 dias de suprimento de alimentos vivos. Também é possível concluir que o fornecimento de alimentação comercial, como alimento exclusivo, é inviável na larvicultura de nishikigoi.(AU)