Temperature increase impairs recognition among nestmates in the social wasp Polybia paulista H. von Ihering, 1896 (Vespidae: Polistinae: Epiponini)

Cuticular hydrocarbons (CHCs) of most terrestrial arthropods primarily serve as a protective barrier against desiccation and infection. Throughout evolution, these compounds have acquired another fundamental function: the exchange of signals during interactions between nestmates. However, even though cuticular hydrocarbons perform a dual function in social insects, little is known about the effect(s) of one function on the other in social insects, and no study has evaluated this relationship in social wasps. Therefore, the present study tests the hypothesis that the level of aggressiveness presented during induced encounters between nestmates of Polybia paulista who were subjected to different conditions temperature is different than between nestmates who remained under the same temperature conditions. If the hypothesis is confirmed, it is likely because the cuticle of the wasps that had been exposed to temperature variation adjusted to these conditions leading them not to recognize the cuticular chemical signature of their colony. To test this hypothesis, workers were exposed to temperature variation in a BOD chamber and then subjected to encounters with workers who were maintained at a constant temperature of 24℃. We also used control groups to evaluate the effect of isolation alone among the groups. According to our results, our hypothesis was confirmed, the level of aggressiveness presented between nestmates who were exposed to temperature variation and those who remained at 24℃ was significantly higher than the levels of aggressiveness presented between nestmates who remained isolated but under constant temperature during the same period, in some cases, it was similar to the aggressiveness presented in encounters between wasps from different colonies. During these encounters, wasps performed alarm behavior, bites, and stings not seen during encounters between wasps that remained under the same temperature, but in isolated groups. The lack of aggressive behavior under isolated conditions indicates that isolation had no effect on chemical recognition signature. These results suggest that temperature variation may have caused some change in the cues that allow recognition between nestmates. On the other hand, these results were not caused by isolation or stress generated by the study design and difference in the CHC profile of workers, as described in the literature, is consistent with our results

The isolation and characterization of endophytic microorganisms from Hyptis marrubioides Epling roots

Endophytic microorganisms asymptomatically colonize healthy plant tissues and may be related to the plant's resistance to attack by pathogens or even to the synthesis of secondary metabolites. The present study was aimed at isolating and characterizing endophytic strains from the root system of Hyptis marrubioides. Coarse and fine root fragments were collected for diaphanization and surface disinfection to isolate endophytes. After 10 days of incubation, we obtained the colonization rate (CR) of the fragments and the endophytic were purified and maintained in culture medium. The bacteria were partially characterized using Gram stain and a catalase test. Fungi were identified by distinguishing between reproductive structures using a microculture technique. While observing diaphanized root fragments, we found arbuscular mycorrhizal fungi (AMF) and dark septate endophytic (DSE) fungi in the fine and coarse roots of H. marrubioides. The endophytic CR was more significant in coarse root fragments. In both types of roots, the percentage of bacteria was higher than the percentage of fungi. Gram positive and catalase-positive bacteria accounted for the majority of bacterial isolates, which were predominantly bacilli. Of all the fungal isolates, the majority had sporulating mycelium, which mainly consisted of fungi from the genus Penicillium, Fusarium, Trichoderma and Papulaspora.Keywords: Bacteria, fungus, Lamiaceae, root syste

Atividade enzimática da lipase em rã-touro na fase pós-metamórfica

The knowledge of the digestive system of bullfrogs is an important step for the determination of their nutritional requirements throughout growth phases. With the objective of evaluating the enzymatic activity of lipase in the intestinal content of bullfrogs (Rana catesbeiana Shaw, 1802), 100 animals with median weight of 3.6 g were distributed in stalls under controlled temperature and photoperiod. The frogs, selected at the post-metamorphic phase, received commercial extruded diet ad libitum throughout the 87-day experiment. The collections of the intestinal content were performed by the desensitization of the frogs in ice and water at 0ºC and subsequent isolation of the small intestine. Determination of lipase activity was performed with a commercial enzymatic kit (Lipase-Bioclin, MG, Brazil), first measured in samples taken at day three (3.46 UI). During the initial phase the bullfrog possesses low lipase hydrolysis capacity was found, having a specific activity of 217 UI mg-1. In the subsequent period both lipase activity and specific lipase activity continuously increased. Lipase activity as a function of bullfrog weight fell after day twenty and reached 0.33 UI g-1, for frogs of medium weight (179 g). Feed for bullfrogs at the post-metamorphic phase weighing more than 10 g can have larger amounts of ingredients containg lipids, due to the increased digestive capacity of these frogs.O conhecimento do sistema digestório da rã-touro é um passo importante para a determinação de sua exigência nutricional nas diferentes fases de crescimento. Com o objetivo de avaliar a atividade enzimática da lipase no conteúdo intestinal da rã-touro (Rana catesbeiana Shaw, 1802), 100 animais com peso médio de 3,6 g foram distribuídos em baias-teste com temperatura e fotoperíodo controlados. As rãs, selecionadas na fase pos-metamórfica receberam ração extruzada comercial ad libitum. Durante 87 dias de experimento, 29 coletas (87 rãs) foram feitas em intervalos que variaram de um a oito dias. As rãs foram insensibilizadas em água e gelo a 0ºC para subseqüente isolamento do intestino delgado e retirada do conteúdo intestinal. Para determinação da atividade da lipase foram usados conjuntos enzimáticos da BIOCLIN. A atividade da lipase foi registrada no terceiro dia (3,46 UI). Na fase inicial, a rã-touro possui baixa capacidade de hidrólise para a lipase que teve atividade específica de 217 UI mg-1. No período subseqüente, observou-se aumento contínuo da atividade e da atividade específica da lipase. A atividade da lipase em função do peso da rã-touro depois do 20º dia apresentou redução contínua, alcançando valor de 0,33 UI g-1, registrado para rãs com peso médio de 179 g. As rações para rã-touro com peso superior a 10 g podem conter quantidades maiores de ingredientes que contenham lipídos, devido ao aumento da capacidade da digestão

Free Amino Acids Analysis in the Venom of the Social Wasp Polistes lanio Under Different Forms of Preservation

Venoms of social wasps have in their composition proteins, peptides, among others and several of these compounds were evaluated for their function in the venom, however, there is still no study of the quantification of free amino acids of venom of social wasps. The peptides and proteins of the venom can originate in the medium amino acids or other molecules by the rupture of the peptide bonds. Therefore, the objective was evaluated the composition of the free amino acid in venom of the social wasp Polistes lanio and validated a method for free amino acids analysis using different forms of preservation of this venom. For this, the venom of P. lanio was analyzed direct and partitioned (liquid-liquid with organic solvents) by High Performance Liquid Chromatography. For validation of the amino acids, parameters as linearity, stability and recovery of the assay method were evaluated by the analyzing it fresh or frozen, and before or after extraction with organic solvents. The free amino acids were recovered from these samples at rates ranging from 93.2-99.0%. The data obtained indicate that the freezing, storage and extraction with organic solvents does not lead to an increase in the amino acids content of proteins and peptides. DOI: http://dx.doi.org/10.17807/orbital.v10i1.100

COOPERAÇÃO DESCENTRALIZADA NA AMAZÔNIA: GANHOS E DESAFIOS DA RELAÇÃO SINO-PARAENSE

O presente trabalho tem como objetivo analisar a evolução histórica da cooperação sino-paraense levando em conta variáveis como as mudanças recentes das diretrizes da Política Externa Brasileira e da economia internacional, para então, identificar os aspectos estratégicos dessa relação. Concluímos que a cooperação descentralizada sino-paraense está centralizada nas dimensões econômica e comercial, com possíveis avanços na dimensão sociocultural, o que demanda esforços, por parte da diplomacia federativa e da paradiplomacia executada pelo estado do Pará, para avançar em dimensões estratégicas como a tecnológica, informacional e ambiental, como meios de dirimir a dependência econômica do estado e melhor gerir os custos da interdependências, tais como a sensibilidade e a vulnerabilidade locais

Análise do perfil químico cuticular de fêmeas e imaturos de Latrodectus geometricus (Araneae: Theridiidae) usando GC×GC/qMS

Communication in spiders can occur by several mechanisms, such as chemical cues and the cuticular hydrocarbons (CHCs) play an important role in intraspecific recognition. Several techniques have been used to evaluate CHCs in spiders, such as Gas Chromatography with Flame Ionization Detection, Gas Chromatography coupled with Mass Spectrometric detection and recently Fourier Transformed Infrared Photoacoustic Spectroscopy. In this study, rapid-scanning two-dimensional gas chromatography with quadrupole mass spectrometry (GC×GC/qMS) was employed to assess the CHCs of L. geometricus females and juveniles of different ages. The results demonstrate that there is variation in CHCs of different body parts of females, with abdomen presenting greater number of compounds, as well as between adults and juveniles. Branched alkanes represented the majority of compounds in all samples, followed by linear alkanes, and alkenes were only present in adult’s abdomen and cephalothorax. The compounds 10-methyloctacosaneand 14-methyloctacosane; and 10-methyltriacontane and 14-methyltriacontane showed the same retention time in the 1D and were separated in the 2D. According to the results, rapid-scanning GC×GC/qMS can be considered a reliable technique to assess CHCs since it was possible to identify the spider’s cuticular compounds, and detect and separate two cases of chromatographic coelution.A comunicação em aranhas pode ocorrer por vários mecanismos, especialmente sinais químicos, e os hidrocarbonetos cuticulares (CHCs) desempenham papel fundamental no reconhecimento intraespecífico. Várias técnicas têm sido utilizadas para avaliar os CHCs em aranhas. Aqui, a Cromatografia bidimensional de varredura rápida com espectrometria de massa quadrupolo foi empregada para avaliar o perfil de CHCs de fêmeas de L. geometricus e imaturos de diferentes idades. Amostras do cefalotórax, abdome e pernas de fêmeas foram usadas para avaliar se há variação em CHCs entre as partes. Para avaliar se há variação entre idades, foram usados imaturos de 5 e 20 dias pós-emergência. Os resultados demonstram que há variação em CHCs de diferentes partes do corpo, com abdome apresentando o maior número de compostos, bem como entre adultos e imaturos. Alcanos ramificados representaram a maioria dos compostos em todas as amostras, seguidos por alcanos lineares. Alcenos só estavam presentes no abdome e cefalotórax das adultas. Os compostos 10-metiloctacosano e 14-metiloctacosano; e 10-metiltriacontano e 14-metiltriacontano tiveram o mesmo tempo de retenção em 1D e foram separados em 2D. De acordo com os resultados, a técnica pode ser considerada confiável, já que foi possível identificar os CHCs da aranha, e detectar e separar dois casos de coeluição cromatográfica

The present and future offshore wind resource in the Southwestern African region

In the last decades, offshore wind harvesting has increased enormously, and is seen as a renewable energy resource with great potential in many regions of the world. Therefore, it is crucial to understand how this resource will evolve in a warming climate. In the present study, offshore wind resource in the Southwestern African region is analysed for the present and future climates. A ROM (REMO-OASIS-MPIOM) climate simulation in uncoupled and coupled atmosphere–ocean mode, at 25 km horizontal resolution, and a multi-model ensemble built with a set of regional climate models from the CORDEX-Africa experiment at 0.44° resolution were used. The projected changes of the offshore wind energy density throughout the twenty-first century are examined following the RCP4.5 and RCP8.5 greenhouse gas emissions scenarios. Characterised by strong coastal-parallel winds, the Southwestern African offshore region shows high values of wind energy density at 100 m, up to 1500 Wm⁻² near the coast, particularly offshore Namibia and west South Africa. Conversely, along Angola’s coast the available offshore wind energy density is lower. Throughout the twenty-first century, for the weaker climate mitigation scenario (RCP8.5), an increase of the offshore wind resource is projected to occur along Namibia and South African western coasts, more pronounced at the end of the century (+ 24%), while a decrease is projected along Angola’s coasts, reaching a negative anomaly of about − 32%. Smaller changes but with the same pattern are projected for the stronger climate mitigation scenario (RCP4.5). The future deployment of offshore floating hub turbines placed at higher heights may allow higher production of energy in this region. Along offshore Namibia and west South Africa, the wind energy density at 250 m showed differences that range between 30 and 50% relative to wind energy density at 100 m

Dear Enemy Phenomenon in the Ant Ectatomma brunneum (Formicidae: Ectatomminae): Chemical Signals Mediate Intraspecific Agressive Interactions

The integrity of ant colonies depends exclusively on social relationships between their individuals, especially the ability of communication between group members, which is mainly mediated through chemical signals. Another important feature of ant behavior is territory defense, since they need to gather large amounts of food to feed their larvae, males and breeding females. Thereby, ants might display behavioral strategies to defend their territories from intruders. Here we investigated whether Ectatomma brunneum displays the Dear Enemy Phenomenon, what is the relationship between Cuticular Hydrocarbon composition and levels of aggression during their intraspecific interactions and which compounds and/or classes of compounds might be the most important to modulate the level of aggression. To test our hypothesis, we evaluated the levels of aggression through behavioral observations during interactions between 23 pairs of colonies nested in two distinct sites at varied distances. Then, we analyzed the cuticular chemical profile of the individuals involved in the interactions, and compared these results with the levels of aggression displayed between colonies tested. The results allow us to confirm our hypothesis that the DEP occurs in E. brunneum. The higher tolerance between closer colonies can be explained due to their kinship level in addition to sharing the same microhabitats. The results also showed there are significant differences in CHCs profiles, especially between colonies nested at relatively greater distances, and it is likely that differences in content of some branched alkanes are the most important to establish these differences and, therefore, the levels of aggression during the interactions

Linear alkanes as a tool to evaluate intraspecific differences in social wasps

Cuticular hydrocarbons are found in the epicuticle of insects and act during interactions between nestmates in social insects. Among the classes of these compounds, branched alkanes stand out acting as flags during intracolonial interactions, therefore, varying significantly intraspecificaly. However, there is evidence that linear alkanes can also act as signals in these interactions and therefore would also be important to assess intraspecific differences in colonies of social insects. Thus, the hypothesis of this study is that linear alkanes can be used as a tool to establish intraspecific relationships in a species of social wasp. Linear alkanes of all developmental stages were evaluated from colonies of the species Mischocyttarus consimilis Zikán (Hymenoptera, Vespidae). 21 linear alkanes were detected, with the majority ranging from n-C26 to n-C33. There is significant variation between the compounds of all developmental stages, both from samples of different colonies and populations. Therefore, the results validate the hypothesis that variation in composition of linear alkanes can be useful to assess intraspecific differences in social wasps

Intraspecific Variation of the Composition of Linear Alkanes in Social Wasp Mischocyttarus consimilis

An important attribute of the evolution and maintenance of sociality in insects is their ability to distinguish members of their own colonies by means of chemical signals during their interactions. Of this type of signals, the cuticular hydrocarbons, responsible among other functions, for intraspecific recognition stand out. Linear alkanes are indicated as the class of compounds that would be most involved in water retention in the body of insects, however, some studies have investigated their role as mediators of interactions. Thus it is possible that there is significant intraspecific variation of its composition, so the objective of this study was to test the hypothesis that linear alkanes vary significantly among populations, castes and sexes, as well as between newly emerged females of different ages of the Mischocyttarus consimilis Zikán 1949 wasp. The samples were analyzed by gas chromatography with flame ionization detector and gas chromatography coupled to mass spectrometry. The results show that there is a significant variation between the chemical cuticular profiles of samples from different populations, as well as between castes, sex and newly emergent workers of different ages. Therefore, it is possible to infer that this class of compounds may vary according to genetic differences between populations, but also by different environmental conditions. The differences between castes, sex and ages suggest that these compounds may also be involved in mediating interactions between nestmates