Reduced genetic diversity and the success of the invasive peacock bass (Cichliformes: Cichlidae)

Abstract Several species of Cichla successfully colonized lakes and reservoirs of Brazil, since the 1960s, causing serious damage to local wildlife. In this study, 135 peacock bass were collected in a reservoir complex in order to identify if they represented a single dominant species or multiple ones, as several Cichla species have been reported in the basin. Specimens were identified by color pattern, morphometric and meristic data, and using mitochondrial markers COI, 16S rDNA and Control Region (CR). Overlapping morphological data and similar coloration patterns prevented their identification using the taxonomic keys to species identification available in the literature. However, Bayesian and maximum likelihood from sequencing data demonstrated the occurrence of a single species, Cichla kelberi. A single haplotype was observed for the 16S and CR, while three were detected for COI, with a dominant haplotype present in 98.5% of the samples. The extreme low diversity of the transplanted C. kelberi evidenced a limited number of founding maternal lineages. The success of this colonization seems to rely mainly on abiotic factors, such as increased water transparency of lentic environments that favor visual predators that along with the absence of predators, have made C. kelberi a successful invader of these reservoirs.

Resumo Muitas espécies de Cichla colonizaram com sucesso lagos e reservatórios do Brasil desde os anos 1960, causando graves prejuízos à vida selvagem nesses locais. Neste estudo, 135 tucunarés foram coletados em um complexo de reservatórios a fim de identificar se representavam uma espécie dominante ou múltiplas espécies, uma vez que diversas espécies de Cichla foram registradas na bacia. Os espécimes foram identificados com base na coloração, dados morfométricos e merísticos, e por marcadores mitocondriais COI, 16S rDNA e Região Controle (RC). A sobreposição dos dados morfométricos e o padrão similar de coloração impediram a identificação utilizando as chaves de identificação disponíveis na literatura. Entretanto, as análises bayesiana e de máxima verossimilhança de dados moleculares demonstraram a ocorrência de uma única espécie, Cichla kelberi. Um único haplótipo foi observado para o 16S e RC, enquanto três foram detectados para o COI, com um haplótipo dominante presente em 98,5% das amostras. A baixa diversidade nos exemplares introduzidos de C. kelberi evidenciou um número limitado de linhagens maternas fundadoras. O sucesso da invasão parece depender de fatores abióticos, como a maior transparência da água de ambientes lênticos que favorece predadores visuais que, atrelado à ausência de predadores, fez do C. kelberi um invasor bem-sucedido nesses reservatórios.

Trophic ecology of Acestrorhynchus falcirostris Cuvier, 1819 in island lakes on the lower stretch of the Solimões River, Amazon Basin

Abstract The aim objective of this study was to determine the trophic ecology of juvenile and adult Acestrorhynchus falcirostris during the rising and flood (high-water) period in six island lakes adjacent to the Solimões River. As such, we investigated: i) the trophic position, through the fractional trophic niche; ii) the niche breadth; iii) niche overlap and iv) the food strategy of the species. The specimens were collected during the years 2014 to 2017, using gillnets with mesh sizes ranging from 30 to 120mm between opposite knots. Through the analysis of stomach contents, the preference in the consumption of items of animal origin was observed. Juveniles consumed insects in greater proportions (IAi% = 50%), while adults consumed fish (IAi%=99,98%). Despite the large supply of food items available in the high-water period, juveniles were the only ones to consume items of allochthonous origin, such as insects. Juveniles presented a different dietary strategy and dietary composition to adults. Juveniles were omnivores with a generalist strategy, while adults were piscivores with a specialist strategy. Thus, the food composition, niche breadth, trophic position and feeding strategy of Acestrorhynchus falcirostris change due to the stage of development.

Resumo O objetivo deste estudo foi determinar a ecologia trófica de juvenis e adultos de Acestrorhynchus falcirostris durante o período de enchente e cheia em seis lagos de ilha adjacentes ao rio Solimões. Assim, investigamos: i) a posição trófica, através do nicho trófico fracional; ii) a largura de nicho; iii) sobreposição de nicho; iv) a estratégia alimentar. Os espécimes foram coletados durante os anos de 2014 a 2017, utilizando redes de emalhar com malha variando de 30 a 120mm entre nós opostos. Por meio da análise do conteúdo estomacal, observamos a preferência no consumo de itens de origem animal. Os juvenis consumiram insetos em maiores proporções (IAi% = 50%), enquanto os adultos consumiram preferencialmente peixes (IAi% = 99,98%). Apesar da grande oferta de alimentos disponíveis no período da cheia, os juvenis eram os únicos a consumir itens de origem alóctone, como por exemplo, os insetos. Os juvenis apresentaram uma estratégia alimentar e composição alimentar diferente para os adultos. Os juvenis foram considerados onívoros com uma estratégia generalista, enquanto os adultos foram considerados piscívoros com uma estratégia alimentar mais especialista. Assim, a composição alimentar, amplitude do nicho, posição trófica e a estratégia alimentar de Acestrorhynchus falcirostris muda em função do estágio de desenvolvimento.

Reduced genetic diversity and the success of the invasive peacock bass (Cichliformes: Cichlidae) / Diversidade genética reduzida e o sucesso da espécie invasora tucunaré (Cichliformes: Cichlidae)

Abstract Several species of Cichla successfully colonized lakes and reservoirs of Brazil, since the 1960's, causing serious damage to local wildlife. In this study, 135 peacock bass were collected in a reservoir complex in order to identify if they represented a single dominant species or multiple ones, as several Cichla species have been reported in the basin. Specimens were identified by color pattern, morphometric and meristic data, and using mitochondrial markers COI, 16S rDNA and Control Region (CR). Overlapping morphological data and similar coloration patterns prevented their identification using the taxonomic keys to species identification available in the literature. However, Bayesian and maximum likelihood from sequencing data demonstrated the occurrence of a single species, Cichla kelberi. A single haplotype was observed for the 16S and CR, while three were detected for COI, with a dominant haplotype present in 98.5% of the samples. The extreme low diversity of the transplanted C. kelberi evidenced a limited number of founding maternal lineages. The success of this colonization seems to rely mainly on abiotic factors, such as increased water transparency of lentic environments that favor visual predators that along with the absence of predators, have made C. kelberi a successful invader of these reservoirs.

Resumo Muitas espécies de Cichla colonizaram com sucesso lagos e reservatórios do Brasil desde os anos 1960, causando graves prejuízos à vida selvagem nesses locais. Neste estudo, 135 tucunarés foram coletados em um complexo de reservatórios a fim de identificar se representavam uma espécie dominante ou múltiplas espécies, uma vez que diversas espécies de Cichla foram registradas na bacia. Os espécimes foram identificados com base na coloração, dados morfométricos e merísticos, e por marcadores mitocondriais COI, 16S rDNA e Região Controle (RC). A sobreposição dos dados morfométricos e o padrão similar de coloração impediram a identificação utilizando as chaves de identificação disponíveis na literatura. Entretanto, as análises bayesiana e de máxima verossimilhança de dados moleculares demonstraram a ocorrência de uma única espécie, Cichla kelberi. Um único haplótipo foi observado para o 16S e RC, enquanto três foram detectados para o COI, com um haplótipo dominante presente em 98,5% das amostras. A baixa diversidade nos exemplares introduzidos de C. kelberi evidenciou um número limitado de linhagens maternas fundadoras. O sucesso da invasão parece depender de fatores abióticos, como a maior transparência da água de ambientes lênticos que favorece predadores visuais que, atrelado à ausência de predadores, fez do C. kelberi um invasor bem-sucedido nesses reservatórios.

Trophic ecology of Acestrorhynchus falcirostris Cuvier, 1819 in island lakes on the lower stretch of the Solimões River, Amazon Basin / Ecologia trófica de Acestrorhynchus falcirostris Cuvier, 1819 em lagos de ilha no trecho inferior do Rio Solimões, Bacia Amazônica

Abstract The aim objective of this study was to determine the trophic ecology of juvenile and adult Acestrorhynchus falcirostris during the rising and flood (high-water) period in six island lakes adjacent to the Solimões River. As such, we investigated: i) the trophic position, through the fractional trophic niche; ii) the niche breadth; iii) niche overlap and iv) the food strategy of the species. The specimens were collected during the years 2014 to 2017, using gillnets with mesh sizes ranging from 30 to 120mm between opposite knots. Through the analysis of stomach contents, the preference in the consumption of items of animal origin was observed. Juveniles consumed insects in greater proportions (IAi% = 50%), while adults consumed fish (IAi%=99,98%). Despite the large supply of food items available in the high-water period, juveniles were the only ones to consume items of allochthonous origin, such as insects. Juveniles presented a different dietary strategy and dietary composition to adults. Juveniles were omnivores with a generalist strategy, while adults were piscivores with a specialist strategy. Thus, the food composition, niche breadth, trophic position and feeding strategy of Acestrorhynchus falcirostris change due to the stage of development.

Resumo O objetivo deste estudo foi determinar a ecologia trófica de juvenis e adultos de Acestrorhynchus falcirostris durante o período de enchente e cheia em seis lagos de ilha adjacentes ao rio Solimões. Assim, investigamos: i) a posição trófica, através do nicho trófico fracional; ii) a largura de nicho; iii) sobreposição de nicho; iv) a estratégia alimentar. Os espécimes foram coletados durante os anos de 2014 a 2017, utilizando redes de emalhar com malha variando de 30 a 120mm entre nós opostos. Por meio da análise do conteúdo estomacal, observamos a preferência no consumo de itens de origem animal. Os juvenis consumiram insetos em maiores proporções (IAi% = 50%), enquanto os adultos consumiram preferencialmente peixes (IAi% = 99,98%). Apesar da grande oferta de alimentos disponíveis no período da cheia, os juvenis eram os únicos a consumir itens de origem alóctone, como por exemplo, os insetos. Os juvenis apresentaram uma estratégia alimentar e composição alimentar diferente para os adultos. Os juvenis foram considerados onívoros com uma estratégia generalista, enquanto os adultos foram considerados piscívoros com uma estratégia alimentar mais especialista. Assim, a composição alimentar, amplitude do nicho, posição trófica e a estratégia alimentar de Acestrorhynchus falcirostris muda em função do estágio de desenvolvimento.

Predatory bacterial hydrogels for topical treatment of infected wounds

Wound infection is becoming a considerable healthcare crisis due to the abuse of antibiotics and the substantial production of multidrug-resistant bacteria. Seawater immersion wounds usually become a mortal trouble because of the infection of Vibrio vulnificus. Bdellovibrio bacteriovorus, one kind of natural predatory bacteria, is recognized as a promising biological therapy against intractable bacteria. Here, we prepared a B. bacteriovorus-loaded polyvinyl alcohol/alginate hydrogel for the topical treatment of the seawater immersion wounds infected by V. vulnificus. The B. bacteriovorus-loaded hydrogel (BG) owned highly microporous structures with the mean pore size of 90 μm, improving the rapid release of B. bacteriovorus from BG when contacting the aqueous surroundings. BG showed high biosafety with no L929 cell toxicity or hemolysis. More importantly, BG exhibited excellent in vitro anti-V. vulnificus effect. The highly effective infected wound treatment effect of BG was evaluated on mouse models, revealing significant reduction of local V. vulnificus, accelerated wound contraction, and alleviated inflammation. Besides the high bacterial inhibition of BG, BG remarkably reduced inflammatory response, promoted collagen deposition, neovascularization and re-epithelization, contributing to wound healing. BG is a promising topical biological formulation against infected wounds.

Considering the role of the assassin snail Anentome helena as a biological control of Bithynia siamensis goniomphalos, the first intermediate host of Opisthorchis viverrini

This study aims to investigate whether the assassin snail Anentome helena may serve as a biological control agent of Bithynia siamensis goniomphalos, the 1st intermediate host of Opisthorchis viverrini. Experiments were carried out in the laboratory, and the results found that A. helena showed the variation and selection of mollusc prey. A. helena can consume B. siamensis goniomphalos, which is remarkable because this snail can compete with other snails and could be used as a biological control. The consumption rate of the predator was compared, and it was found that A. helena prefers to consume Indoplanorbis exustus, followed by Pomacea canaliculata, Melanoides tuberculata, Filopaludina sumatrensis speciosa, Lymnaea sp., and B. siamensis goniomphalos. This is the first report of an experimental study controlling B. siamensis goniomphalos using A. helena. Our data imply that A. helena can control the B. siamensis goniomphalos population with good results, especially in the absence of other snail species.

Trophic relationship between Chrysoperla externa (Neuroptera: Chrysopidae) and Planococcus citri (Hemiptera: Pseudococcidae) associated with rose bushes

ABSTRACT This study aimed to determine the consumption of Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) nymphs and the predator:prey ratio required for high predatory efficacy and survival of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) larvae under different densities of prey, reared in rose bushes. Consumption by first-, second-, and third-instar larvae of C. externa was assessed. The predatory efficiency and survival of the predator were calculated for larvae in the second instar under densities of 20, 40, 80, 120, and 160 nymphs of P. citri and predator:prey ratios of 1:5, 1:10, and 1:20. The assessments were performed after 24 and 48 hours of exposure between species. There was increasing consumption throughout the larval development of C. externa. The predator:prey ratios 1:5 and 1:10 were the most efficient for P. citri population reduction, but the 1:5 ratio led to lower survival of larvae than the 1:10 and 1:20 ratios. There was a positive correlation between C. externa larval density and cannibalism (ρ = 0.45) and a negative correlation between predator density and P. citri population density (ρ = -0.81). Third-instar larvae consume more P. citri nymphs than second-instar larvae. Second-instar larvae of this lacewing released at a 1:20 ratio caused total mortality of mealybug nymphs within 48 hours, regardless the density of P. citri, with high larvae survival of C. externa.

Inter - and intraspecific relationships between Macrosiphum rosae (Hemiptera: Aphididae) and Chrysoperla externa (Neuroptera: Chrysopidae)

ABSTRACT The predator Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) is a polyphagous species that has, among its wide range of acceptable prey, the aphid Macrosiphum rosae (Linnaeus, 1758) (Hemiptera: Aphididae), an important pest of rose plants. We assessed the consumption of nymphs and adults of M. rosae by C. externa larvae, the predatory efficiency, and larval survival under different predator:prey ratios, densities of aphids, and ages of aphids. The bioassays were performed at 25 ± 1°C and 70 ± 10% RH under a 12-hour photoperiod, with aphids taken from roses of the cultivar Avalanche. Consumption was assessed by making young aphids (2nd and 3rd instars) and more developed aphids (4th instar and adult) available throughout the larval stage of the predator. The predatory efficiency and survival were studied for second-instar larvae offered M. rosae nymphs at densities of 20, 40, 80, 120, and 160 using predator:prey ratios of 1:5, 1:10, and 1:20. The assessments were performed 24, 48, and 72 hours after putting the species together. All of the C. externa instars consumed younger than older aphids. Larvae in the third instar consumed 80% of the young aphids and 77% of the older aphids. The higher the predator:prey ratio and larval density, the higher the predatory efficiency and the lower the larval survival. The ratios 1:5 and 1:10 led to the elimination of younger and older aphid populations 72 hours into the interaction between species.

Voracity, reaction to stings, and survival of domestic hens when feeding on the yellow scorpion (Tityus serrulatus)

Scorpionism is a worldwide problem that has already made thousands of victims, and multi-disciplinary approaches for controlling their populations are to be more successful. Hens are often mentioned as tools for controlling scorpions; however, systematic/experimental behavioral studies are not available. Moreover, there is no systematic information on the effect of scorpion venoms on hens. Using the venomous yellow scorpion Tityus serrulatus, the present study aimed to clarify the following aspects: (1) voracity of hens, (2) how hens react when stung, (3) the effect of scorpion stings on hen behavior during attacks, and (4) hen survivorship after feeding on scorpions. Methods: We attracted hens with corn powder, offered them scorpions and then recorded the hen-scorpion interaction. To test the effects of the sting we manually removed the scorpion's telson. Results: We found that some hens ate up to six scorpions within minutes. By means of an ethogram and drawings, we showed that they exhibited several aversive behaviors when capturing scorpions. Removal of the scorpion telson stopped the aversive reactions, which was not observed in the control group. Finally, hens did not exhibit atypical behaviors after 1, 7 and 30 days and were all alive after 30 days. Conclusion: This is the first empirical and video recorded study providing evidence that hens are clearly affected by scorpion venom but do not die. Therefore, they may have potential to be used in biological control of these arthropods.(AU)

Voracity, reaction to stings, and survival of domestic hens when feeding on the yellow scorpion (Tityus serrulatus)

Abstract Background: Scorpionism is a worldwide problem that has already made thousands of victims, and multi-disciplinary approaches for controlling their populations are to be more successful. Hens are often mentioned as tools for controlling scorpions; however, systematic/experimental behavioral studies are not available. Moreover, there is no systematic information on the effect of scorpion venoms on hens. Using the venomous yellow scorpion Tityus serrulatus, the present study aimed to clarify the following aspects: (1) voracity of hens, (2) how hens react when stung, (3) the effect of scorpion stings on hen behavior during attacks, and (4) hen survivorship after feeding on scorpions. Methods: We attracted hens with corn powder, offered them scorpions and then recorded the hen-scorpion interaction. To test the effects of the sting we manually removed the scorpions telson. Results: We found that some hens ate up to six scorpions within minutes. By means of an ethogram and drawings, we showed that they exhibited several aversive behaviors when capturing scorpions. Removal of the scorpion telson stopped the aversive reactions, which was not observed in the control group. Finally, hens did not exhibit atypical behaviors after 1, 7 and 30 days and were all alive after 30 days. Conclusion: This is the first empirical and video recorded study providing evidence that hens are clearly affected by scorpion venom but do not die. Therefore, they may have potential to be used in biological control of these arthropods.

Water column use by reef fishes of different color patterns

Color in animals responds to selective pressures and mediates the relationship between organism and environment. Reef fishes have the amplest variety of pigment cell types. This color patterns' variety may function as camouflage and be related to spatial use. We tested the hypothesis that the coloration of reef fish relates to water column stratum occupation. We predicted that sedentary animals connected to the background take advantage of background matching or disruptive patterns; more mobile demersal species apply disruptive coloration or motion-dazzle; and that pelagic species tend to have silvery bodies. We classified color patterns and categorized the water column stratum use for the Brazilian reef fishes in FishBase. Our analyses confirmed that irregular contrasting contour breaks, suggestive of disruptive coloration, occurs in benthic species and that silvering color was more prevalent in the pelagic stratum. Our raw data suggested a higher frequency of contrasting regular stripes, typical of motion-dazzle, in demersal species. However, the considerable uncertainty around estimates did not confirm this pattern. Reef fishes coloration is correlated to occupation of different strata in the water column. This can be interpreted as fishes being adapted to these habitats and partially explaining the richness of color patterns among them.(AU)

A cor nos animais responde a pressões seletivas e media a relação entre organismo e ambiente. Peixes recifais têm a maior variedade de tipos de células de pigmento. Essa variedade de padrões de coloração pode funcionar como camuflagem e estar relacionada ao uso espacial. Nós testamos a hipótese de que a coloração dos peixes recifais está relacionada à ocupação do estrato da coluna d'água. Previmos que animais sedentários conectados ao fundo aproveitam a semelhança ao fundo ou padrões disruptivos; espécies demersais mais móveis aplicam coloração disruptiva ou deslumbramento de movimento; e que espécies pelágicas tendem a apresentar corpos prateados. Classificamos os padrões de coloração e categorizamos o uso do estrato da coluna d'água para os peixes recifais brasileiros no FishBase. Nossas análises confirmaram que quebras de contorno irregulares, sugerindo coloração disruptiva, ocorrem em espécies bentônicas e que a cor prateada prevaleceu no estrato pelágico. Nossos dados brutos sugeriram uma maior frequência de listras contrastantes, típicas do deslumbramento de movimento, em espécies demersais. Mas a considerável incerteza dessas estimativas não confirmou esse padrão. A coloração dos peixes recifais está correlacionada com a ocupação de diferentes estratos da coluna d'água. Isso pode ser interpretado como peixes sendo adaptados a estes habitats, explicando em parte a riqueza de padrões de coloração entre eles.(AU)

Revistas depredadoras y su identificación: revisión sistemática / Predatory Journals and their Identification: Systematic Review

Introducción: las revistas depredadoras son una amenaza global debido a que aceptan manuscritos para su publicación por honorarios, sin realizar los controles de calidad prometidos. Los lectores ingenuos no son las únicas víctimas, investigadores novicios también han sido engañados para que envíen sus manuscritos a estas revistas. Objetivo: el objetivo fue identificar las características de una revista depredadora. Materiales y métodos: se llevó a cabo una revisión sistemática siguiendo las directrices PRISMA (Preferred Reporting Items for Systematic reviews and Meta Analyse) de los estudios empíricos encontrados en PubMed, SciELO, Elsevier y Google Académico con los términos MeSH ("revistas depredadoras" o "predatory journal and systematic review"). Resultados: se localizaron 81 escritos con los términos señalados y se seleccionaron seis posibles artículos, de los que solo se tuvo acceso a cuatro. Conclusiones: no existe una lista de verificación única e infalible, pero se señalan que las revistas depredadoras carecen de registros en DOAJ (Directory of Open Access Journals), ICMJE (International Committee of Medical Journal Editors) y COPE (Committee on Publication Ethics); así mismo, es necesario verificar si el editor es miembro de organizaciones editoriales conocidas, si el sitio web de las revistas contiene información actual y confiable, y si está indexada en PubMed; para esto, consulte MEDLINE.

Introduction: Predatory journals are a global threat, because they accept manuscripts for publication for fees, without performing the promised quality controls. Naïve readers are not the only victims, novice researchers have also been tricked into submitting their manuscripts to these journals. Objective: The objective was to identify the characteristics of a predatory magazine. Materials and methods: A systematic review has been carried out following the PRISMA Preferred Reporting Items for Systematic reviews and Meta-Analyse guidelines of the empirical studies found in PubMed, SciELO, Elsevier and academic Google with the MeSH terms ("predatory journals" or "predatory journal and systematic review"). Results: 81 writings with the indicated terms were located, selecting six possible articles, in which only four writings were accessed. Conclusions: There is no single and infallible checklist, but it is pointed out that predatory journals: lack records in DOAJ, ICMJE, COPE, likewise it is necessary to verify if the editor is a member of known publishing organizations, if the website of journals contains current and reliable information, if indexed in PubMed; for this, see MEDLINE.

Simulación de la dinámica de la biomasa en plancton de un embalse colombiano tropical andino de alta montaña / Simulation of biomass dynamics in plankton of a high-altitude andean tropical reservoir in colombia

ABSTRACT The understanding of the relationships between the planktonic communities in a reservoir allows us to infer possible changes in the redistribution of matter and energy flows in these systems. This work proposes a dynamic model for the trophic network of the Riogrande II tropical reservoir, which integrates the planktonic trophic chains of detritus and grazing, limiting the prey-predator interactions by introducing the prey meeting factor (pmf). We built a dynamic model of mass balance supported by an extensive bibliographic search. The limitations of consumers and resources were represented simultaneously by means of the pmf. The data used to validate the model were compiled from previous investigations carried out in this reservoir from 2010 to 2013. The values of pmf that we found in each simulation suggest that the top predator can access its main prey in certain concentrations of total phosphorus, with a probability of encounter ranging from 9.3 % to 17.7 %. Our simulations indicate that most of the primary production is poorly used by the primary consumers in the photic zone, however, it enters in the flows of the detrital chain and supports the production of zooplankton almost entirely. According to this finding, the biomass densities obtained in the previous studies can be better explained by the causal relationships assumed in this model.

RESUMEN Entender las relaciones entre las comunidades planctónicas en un embalse nos permite inferir posibles cambios en la redistribución de los flujos de materia y energía en este sistema. Este trabajo propone un modelo dinámico para representar la red trófica del embalse tropical Riogrande II, donde se integran las cadenas tróficas de pastoreo y detritus y se limitan las interacciones entre predadores, presas y recursos al introducir un factor limitante de encuentro con la presa (pmf). El modelo dinámico se enfoca en el balance de masas sustentado en una amplia búsqueda bibliográfica. Los datos usados para validar el modelo se colectaron de datos previamente reportados para el embalse durante los años 2010 y 2013. Los valores de pmf obtenidos en cada simulación, sugieren que el predador dominante puede acceder a su presa principal a ciertas concentraciones de fósforo total, con una probabilidad de encuentro que va desde 9,3 % hasta 17,7 %. Nuestros resultados indican que la mayor parte de la producción primaria es poco aprovechada por los consumidores en la zona fótica, sin embargo, ingresa en el flujo de la cadena detrítica de manera que soporta la producción de zooplancton casi por completo. Las relaciones causales asumidas en este modelo explican en gran medida las densidades de biomasa reportadas en estudios previos.

PREDATORY INTERACTION BETWEEN TWO ANURAN SPECIES WITH Thamnodynastes chaquensis (COLUBRIDAE) IN THE BRAZILIAN CERRADO / Interacción depredatoria entre dos especies de anura con Thamnodynastes chaquensis (Colubridae) en el Cerrado brasileño

ABSTRACT Although predatory events are uncommon to be recorded in nature, these data are important tools for understanding prey-predator interaction of the involved species. Snakes of genus Thamnodynastes are known for having an anuran diet, including some species of hylid frogs in their diet. Despite this, this pattern does not include T. chaquensis since there are no records on predation or trophic interaction with hylid frogs. Here, we report the first predatory interaction between T. chaquensis and two hylid frogs in Brazilian Cerrado. The first predation event with treefrog Boana caiapo occurred with success but, the second with B. albopunctata did not. Connecting trophic links within an ecosystem requires in-depth knowledge of its species and their intraspecific interactions. In this context, records of the predation and predation attempts such as these may help to connect unknown trophic links, which helps to understand aspects of the natural history of the species involved.

RESUMEN Aunque los eventos depredatorios son poco comunes de registrar en la naturaleza, estos datos son herramientas importantes para comprender la interacción presa-depredador de las especies involucradas. Las serpientes del género Thamnodynastes son conocidas por su dieta basada en anuros y, aunque algunas especies incluyen ranas hílidas en su dieta, esto no ocurre en la especie T. chaquensis porque no hay registros de depredación o interacción trófica con los hílidos. Aquí informamos sobre la primera interacción depredatoria entre T. chaquensis y dos ranas hílidas del Cerrado brasileño. El primer evento de depredación con la rana Boana caiapo fue exitoso, pero el segundo con B. albopunctata no. Conectar los enlaces tróficos dentro de un ecosistema requiere conocer íntimamente sus especies y sus interacciones intraespecíficas. En este contexto, los registros de depredación y de intentos de depredación como estos pueden ayudar a conectar enlaces tróficos no conocidos, lo cual ayuda a comprender los aspectos de la historia natural de las especies involucradas.

Predator preferences: a key to effective biological control design / Preferências do predador: a chave para um projeto de controle biológico eficaz

Objetctive: This experimental study aimed to assess the preference of Gambusia affinis to mosquito larvae of An.gambiae s.s., Cx. quinquefasciatus and Aedes aegypti. Method: Three Gambusia affinis were introduced in a glass container with a dimension of 45cm x 25cmx 25cm. Three larvae densities were used, 90 (30 larvae per species), 120 (40 larvae per species), and 180 (60 larvae per species). Each density experiment was set in triplicate and monitored after 1, 2, 3, and 24 hours. No fish food was added to the container for larvae. Results: Results have shown that in all times A. aegypti has been the most preferred species by Gambusia affinis. Among the tested species, A. aegypti was most prayed with time and in different densities. In mixed models including density, species, and time there was no significant difference among the species predation. Conclusion: Preliminary results have shown that the appropriate choice of predators for each mosquito species can have a great impact on bio-control to substantially complement existing tools.

Objetivo: avaliar a preferência de Gambusia affinis por larvas de mosquito de An. gambiae s.s., Cx. quinquefasciatus e Aedes aegypti. Método: Três Gambusia affinis foram introduzidos em um recipiente de vidro com dimensões de 45cm x 25cm x 25cm. Foram utilizadas três densidades de larvas, 90 (30 larvas por espécie), 120 (40 larvas por espécie) e 180 (60 larvas por espécie). Cada experimento de densidade foi estabelecido em triplicado e monitorado após 1, 2, 3 e 24 horas. Nenhum alimento de peixe foi adicionado ao recipiente com larvas. Resultados: Os resultados mostraram que em todos os tempos o A. aegypti foi a espécie mais preferida por Gambusia affinis. Entre as espécies testadas, A. aegypti foi a mais predada com o tempo e em diferentes densidades. Em modelos mistos incluindo densidade, espécie e tempo, não houve diferença significativa entre a predação por espécies. Conclusão: Os resultados preliminares mostraram que a escolha apropriada de predadores para cada espécie de mosquito pode ter um grande impacto no bio-controle para complementar substancialmente as ferramentas existentes.

Feeding habits of the Robber Frog Pristimantis paulodutrai (Bokermann, 1975) in northeastern Brazil / Hábitos alimentares da rã Pristimantis paulodutrai (Bokermann, 1975) no nordeste do Brasil

Abstract: Studying feeding habits is crucial to understand complex predator-prey interactions. Even though anurans play a fundamental role in the control of arthropods populations, the diet of several Neotropical species is poorly known. We describe the frequency and occurrence of prey items and their dry mass in stomach contents of the Robber Frog Pristimantis paulodutrai in the north east of the state of Bahia, Brazil. Based on the stomach contents of 30 individuals, Araneae, Isopoda, and Formicidae were found to be the most important food items. The generalist diet of this frog, which seems to be phylogenetically conserved among Pristimantis, is likely to be linked to its ecological dominance in the habitats surveyed. Our study corroborates the high trophic relevance of Robber Frogs in tropical forests as generalist predators.

Resumo: Estudar hábitos alimentares é crucial para entender as complexas interações predador-presa. Embora os anuros tenham papel fundamental no controle das populações de artrópodes, a dieta de várias espécies neotropicais é pouco conhecida. Descrevemos a frequência e a ocorrência de presas e sua massa seca no conteúdo estomacal da rã Pristimantis paulodutrai, no nordeste do estado da Bahia, Brasil. Com base no conteúdo estomacal de 30 indivíduos, Araneae, Isopoda e Formicidae foram os itens alimentares mais importantes. A dieta generalista desta rã, a qual parece ser conservada filogeneticamente entre os Pristimantis, provavelmente está ligada à sua dominância ecológica nos habitats pesquisados. Nosso estudo corrobora a alta relevância trófica dos Robber Frogs em florestas tropicais como predadores generalistas.

Hair as a tool for identification of predators and prey: a study based on scats of jaguars (Panthera onca) and pumas (Puma concolor) / Pelos como ferramenta de identificação de predadores e presas: um estudo baseado em fezes de onças-pintadas (Panthera onca) e pumas (Puma concolor)

Abstract: Microscopic hair identification is a non-invasive, simple, and economical method applied in scientific studies to identify mammal species. In ecology, this method is used mainly in mastofaunistic inventories and dietary studies. In the last decade, the number of dietary studies using the microscopic identification of hairs has grown substantially, but the application of this technique as a tool for the identification of both predators and prey species is still scant. Thus, the aim of this study was to identify predator and prey hairs in scat samples from the two largest species of carnivores in the Neotropical region, the jaguar (Panthera onca Linnaeus, 1758) and the puma (Puma concolor Linnaeus, 1771). We examined a total of 100 scat samples being 50 from the Pantanal of Mato Grosso do Sul and 50 from the Atlantic Forest of Paraná. We used different identification categories that included the hair microscopic and macroscopic identification, as well as the use of hooves and nails present in the scats associated with tracks and kills found in the field. We identified 57 prey items in the Pantanal samples and 61 in the Atlantic Forest samples. Predator´s hairs were identified in 34% of Pantanal samples and in 46% of Atlantic Forest samples. The combination of hair microscopic and macroscopic characteristics was efficient in the identification of different taxonomic levels, with most identifications reaching the level of the species. However, the methodological protocol for microscopic hair identification was not fully effective in obtaining all the microstructural patterns of the studied mammals. Adjustments in the technique are necessary to differentiate microstructural characteristics of species belonging to the same family. We recommend macroscopic identification of scat content items (hairs, hooves or nails) of both prey and predators to be used to complete the microscopic hair identification technique in dietary ecological studies.

Resumo: A identificação microscópica do pelo é um método não invasivo, simples e econômico, aplicado em estudos de identificação de várias espécies. Em ecologia, esse método é usado principalmente em inventários mastofaunísticos e estudos de dieta. Na última década, a identificação microscópica de pelos em estudos de dieta tem crescido substancialmente, porém ainda conhecemos muito pouco sobre o uso das características microscópicas e macroscópicas dos pelos para identificação tanto de presas quanto de predadores. Assim, o objetivo deste estudo foi identificar pelos de predadores e presas em amostras fecais das duas maiores espécies de carnívoros da região Neotropical, onças (Panthera onca Linnaeus, 1758) e pumas (Puma concolor Linnaeus, 1771). Foram examinadas um total de 100 amostras de fezes, provenientes do Pantanal de Mato Grosso do Sul e da Mata Atlântica do estado do Paraná, sendo 50 amostras de cada local. Utilizamos diferentes categorias de identificação que incluíam a identificação microscópica e macroscópica do pelo, bem como o uso de outros vestígios como cascos e unhas presentes nas fezes e pegadas e carcaças encontradas em campo. Nós identificamos 57 itens de presas nas amostras do Pantanal e 61 itens de presas nas amostras da Mata Atlântica. Pelos dos predadores foram identificados em 34% das amostras do Pantanal e 46% das amostras da Mata Atlântica. A combinação de características microscópicas e macroscópicas dos pelos foi eficiente na identificação de diferentes níveis taxonômicos, com a maioria das identificações atingindo o nível da espécie. No entanto, o protocolo metodológico de identificação microscópica dos pelos não foi totalmente eficaz para obter todos os padrões microestruturais dos mamíferos estudados. São necessários ajustes na técnica para diferenciar características microestruturais de espécies pertencentes à mesma família. Recomendamos que a identificação macroscópica de itens alimentares (pelos, cascos ou unhas) tanto de presas quanto de predadores seja usada para completar a técnica de identificação microscópica dos pelos em estudos de ecologia alimentar..

First record of the parasitoid wasp Lymeon sp. (Ichneumonidae: Cryptinae) associated with spider eggs-sac of Araneus vincibilis (Araneae: Araneidae) in Northeastern Brazil / Primeiro registro da vespa parasitóide Lymeon sp. (Ichneumonidae: Cryptinae) associada ao ovissaco da aranha Araneus vincibilis (Araneae: Araneidae) no Nordeste do Brasil

Abstract Lymeon Förster, 1869 is a very large genus of the Cryptinae (Ichneumonidae) with predominantly Neotropical distribution where females attack small cocoons of various groups of insects and spider eggs-sac. In the present study, we report the first record the interaction between the parasitoid wasp Lymeon sp. (Ichneumonidae), with eggs-sac of spider Araneus vincibilis (Araneidae) in Northeastern Brazil. We observed that although the female of A. vincibilis cares for the eggs that were attacked by Lymeon sp, the wasp larva consumed about 80% of spider eggs, indicating that both maternal care and the physical barrier offered by the eggs-sac may not provide absolute defense against predators.

Resumo Lymeon Förster, 1869 é um grande gênero de Cryptinae (Ichneumonidae) com distribuição predominantemente neotropical, onde fêmeas atacam pequenos casulos de vários grupos de insetos e ovissacos de aranha. No presente estudo, relatamos o primeiro registro da interação entre a vespa parasitoide Lymeon sp. (Ichneumonidae), com o ovissaco da aranha Araneus vincibilis (Araneidae) no Nordeste do Brasil. Observamos que, embora a fêmea de A. vincibilis cuide dos ovos que foram atacados por Lymeon sp, a larva da vespa consumiu cerca de 80% dos ovos da aranha, indicando que tanto o cuidado maternal quanto a barreira física oferecida pelo ovissaco não podem fornecer defesa absoluta contra predadores.

Morphometry of the reproductive system of the predator Podisus nigrispinus (Dallas, 1851) (Hemiptera, Pentatomidae) when submitted to different temperatures / Morfometria do aparelho reprodutor de Podisus nigrispinus (Dallas, 1851) (Hemiptera, Pentatomidae) quando submetidos a diferentes temperaturas

ABSTRACT: In order to manipulate the mass rearing of natural enemies, temperature variations can be used. The effects are widely studied for their survival and developmental duration; however, there is little information about their reproductive system in the literature. Therefore, the purpose of this study was to evaluate the effects of different temperatures on the reproductive system of the predator Podisus nigrispinus (Dallas, 1851) (Hemiptera: Pentatomidae). The predator was kept at temperature conditions of 17, 21, 25, and 29 °C until reaching 15 days of age, the adult stage. The insects were then killed, measured for both weight and size, dissected, and then evaluated for the following parameters: length of the most developed ovariole; number of ovarioles per ovary; number of oocytes per the more developed ovarioles; number of oocytes per P. nigrispinus female; and the total area of the testicles was measured in the male insects. Results showed that as the temperature increased, the parameters were positively affected. These temperature variations can be used to manipulate the mass rearing of P. nigrispinus under controlled conditions.

RESUMO: As variações de temperatura podem ser utilizadas para manipular a criação massal de inimigos naturais e seus efeitos são amplamente estudados para a sobrevivência e duração de desenvolvimento, porém, existem poucas informações sobre o sistema reprodutivo na literatura. Por isso, o objetivo desse trabalho foi avaliar os efeitos de diferentes temperaturas sobre o aparelho reprodutivo do predador Podisus nigrispinus (Dallas, 1851) (Hemiptera: Pentatomidae). O predador foi mantido nas temperaturas de 17, 21, 25 e 29 °C até atingir 15 dias de idade na fase adulta. Esses insetos foram mortos, medido o peso e tamanho, dissecados e avaliados nos seguintes parâmetros: comprimento do ovaríolo mais desenvolvido; número de ovaríolo por ovário; números de ovócitos por ovaríolo mais desenvolvidos; número de ovócitos por fêmea; e, nos machos, área total do testículo. Os resultados evidenciaram que a medida que aumenta a temperatura os parâmetros foram afetados positivamente. Essas variações de temperatura podem ser utilizadas para manipular a criação massal de P. nigrispinus em condições controladas.

A new species of Diomus Mulsant (Coleoptera: Coccinellidae: Diomini) from the eastern Amazon

ABSTRACT A new coccinellid species, Diomus leondai sp. nov. (Coleoptera: Coccinellidae: Diomini) is described from northeast Brazil, São Luis, municipality of Raposa, Cumbique. The specimens collected were found feeding on Phenacoccus solenopsis Tinsley and Phenacoccus sp. on the branches, leaves, and fruits of Abelmoschus esculentus L. Moench, Hibiscus acetosella Welw. ex. Hiern and Hibiscus sabdariffa L. (Malvaceae), and Capsicum spp. and Solanum lycopersicum L. (Solanaceae). Some concepts behind the definition and scope of the genus Diomus and tribe Diomini are analyzed, recognizing the need to better characterize its morphological aspects and establish its composition more precisely.