Network analysis as a tool for ecological interactions studies has been widely used since last decade. However, there are few studies on the factors that shape network patterns in communities. In this sense, we compared the topological properties of the interaction network between flower-visiting social wasps and plants in two distinct phytophysiognomies in a Brazilian savanna (Riparian Forest and Rocky Grassland). Results showed that the landscapes differed in species richness and composition, and also the interaction networks between wasps and plants had different patterns. The network was more complex in the Riparian Forest, with a larger number of species and individuals and a greater amount of connections between them. The network specialization degree was more generalist in the Riparian Forest than in the Rocky Grassland. This result was corroborated by means of the nestedness index. In both networks was found asymmetry, with a large number of wasps per plant species. In general aspects, most wasps had low niche amplitude, visiting from one to three plant species. Our results suggest that differences in structural complexity of the environment directly influence the structure of the interaction network between flower-visiting social wasps and plants.

The present study evaluated the acaricidal activity of essential oils from Eucalyptus citriodora and Cymbopogon nardus on non-engorged larvae of Amblyomma cajennense and Anocentor nitens. In order to carry out the study, six groups were formed, each concentration being a treatment (6.25%, 12.5%, 25%, and 50%, respectively) and also with the creation of a control group (distilled water) and a positive control (Deltametrine). For each treatment, approximately 100 larvae of these ticks were placed onto filter papers (2 x 2 cm) impregnated with the concentrations used to test. Next, the envelopes were closed bearing inside the filter paper with measurements of 6 x 6 cm. For each group, six repetitions were performed, and after 24 h live and dead larvae were counted. This procedure was carried out for two essential oils on the two species of ticks. For A. cajennense, the acaricide efficacy of E. citriodora oil was of 10.8%, 35.3%, 34.5%, and 53.1%, whereas the efficacy of C. nardus was of 0.0%, 0.0%, 0.0%, and 61.1% at concentrations of 6.25%, 12.5%, 25.0%, and 50.0%, respectively. In relation to A. nitens, the acaricide efficacy of E. citriodora oil was of 20.1%, 84.5%, 89.2%, and 100.0%, whereas the efficacy of C. nardus was of 0.0%, 90.8%, 100.0%, and 100.0% at concentrations of 6.25%, 12.5%, 25.0%, and 50.0%, respectively. The results indicate that the essential oils tested showed a promising acaricidal activity mainly on A. nitens larvae.

The present work was aimed at evaluating the in vitro efficacy of thymol on engorged and unengorged larvae of Rhipicephalus sanguineus. In order to perform the study, unengorged larvae were interleaved on filter paper (2 x 2 cm) recently sprayed with thymol in the following concentrations: 0.25%, 0.5%, 1.0%, 1.5%, and 2.0%. For each concentration, ten repetitions of 50 larvae each were performed. A control group was established (water + DMSO) together with a positive control group (Amitraz), with ten repetitions each. Mortality was evaluated after 24 h. For the test with engorged larvae, the same thymol concentrations were used with the larvae being immersed for 5 min and mortality evaluated after 15 days. The values found for thymol efficacy for unengorged larvae were of 21.3%, 17.4%, 19.1%, 32.1%, 37.7% and for engorged larvae 3.0%, 0.0%, 3.0%, 97.0%, and 100.0% in concentrations of 0.25%, 0.5%, 1.0%, 1.5%, and 2.0% respectively. We have concluded that thymol had a deleterious effect on larvae of R. sanguineus, especially on engorged larvae for which 100% mortality was found in higher concentration.

Several studies have shown that habitat complexity is an important factor for the dynamic and stability of interacting species. However, it is not known how the habitat complexity may affect the tolerance of wasp-flower interactions to local extinction. Based on this perspective, in this study, we aimed to compare the tolerance of wasp flower visiting guild to local extinction in two different types of vegetation (Riparian Forest and Rocky Grassland). Through observations made during one year, we verified that the structure of the plant-wasp interaction network differed between the two areas, as well as that the robustness to cumulative extinctions had different patterns.  The simulations of cumulative removal of species showed that the network in the Riparian Forest is more robust against the removal of both plants and wasps than that network in Rocky Grassland, since their extinction curves declined more slowly. Therefore, in our study area, we demonstrate that social wasp-plant interactions in areas with lower structural complexity are less tolerant to extinction (i.e. more fragile). We therefore suggest that studies that aim at biodiversity conservation should focus not only in areas where diversity is high, but also in area with lower species richness for the conservation of ecological roles within communities.

Os opiliões desempenham diferentes serviços ambientais, no entanto há poucas informações quanto a riqueza e distribuição dessas populações em diferentes ecossistemas, mesmo em Unidades de Conservação (UC), como no estado de Minas Gerais, sudeste do Brasil. A partir disso, o objetivo do presente estudo visa analisar a diversidade de opiliofauna de duas Unidades de Conservação inseridas em ecossistemas distintos no estado de Minas Gerais. O Trabalho foi conduzido na Área de Proteção Ambiental do Rio Machado (APA), domínio de Mata Atlântica, e no Parque Nacional das Sempre Vivas (PARNA), área de Cerrado. As coletas foram, realizadas no período de setembro de 2018 a abril de 2019, com esforço amostral de 20 horas para o PARNA e 32 horas para a APA. Foi registrada uma nova espécie de Liogonyleptoides para a Ciência na APA Rio Machado, que possui maior riqueza que o PARNA. Não houve espécies em comum entre as duas áreas estudadas, reflexo de diferentes fatores associados, incluindo alta taxa de endemismo, o que justifica a conservação de ambas as Unidades de Conservação, pois alterações nesses ecossistemas poderiam acarretar a perda de espécies de opiliões para o estado de Minas Gerais.

The state of Minas Gerais has high biodiversity, characterized by strong ecosystem heterogeneity that favors high richness of social wasps. There are currently 109 species known to occur in the state, however, there is lack of information concerning the distribution of these social insects among different ecosystems. The objective of this study was to evaluate social wasp species richness and distributions by ecosystem, thereby generating data for use in discerning relevant and priority environments for vespid conservation in Minas Gerais. We evaluated articles, theses, and dissertations published up to the year 2016 containing data on biodiversity of social wasps in natural and agricultural environments. We found 18 studies, in which the highest reported species richness was in semideciduous seasonal forest (n = 68), followed by Cerrado (n = 53), ombrophilous forest (n = 39), deciduous seasonal forest, and campos rupestres (n = 35). The lowest richness was reported in mixed forest (n = 21) and high-altitude fields (n = 19). Considering the high degree of landscape diversity of the state of Minas Gerais, more studies are needed to accurately assess social wasp diversity in these ecosystems, especially Cerrado. Ombrophilous and deciduous forests should be considered strongly relevant for these social insects, especially the Rio Doce State Park and the Rio Pandeiros Wildlife Refuge.

The forest fragmentation is caused by natural or anthropic actions, which affect negatively the biota and the environmental services rendered by biological diversity. However, there is little information on the reflex of these actions in many different groups of animals, such as social wasps, which are abundant and significantly present in neotropical environments, causing a major impact in the communities they live due to their role in food webs. As their natural enemies, wasps are important in the control of agricultural plagues; in the natural environment, they are nectar collectors, frequent flower visitors, and potential pollinators of many species of plants. These factors justify studies which would evaluate in what way the forest fragmentation acts on these insects biodiversity. This study was carried out in four fragments, each of a different size, located in the municipalities of Inconfidentes and Ouro Fino, in the south of the state of Minas Gerais (Brazil), where the phytophysiognomy is the Montane Semideciduous Seasonal Forest. The research was carried out between December 2016 and March 2018, with the same sampling collection for each fragment, totalizing 104 sampling days. In total, 28 species and 51 colonies were recorded in the four areas and a greater richness for the greatest fragment (F4). The conclusion reached was that the size and heterogeneity of the fragment have an important role in maintaining the richness of social wasps.

As vespas sociais nidificam em diferentes espécies de plantas, no entanto, as informações em relação à possível preferência por determinados tipos de substratos vegetais são escassos em diferentes ecossistemas brasileiros. Nesse panorama o presente estudo tem por objet ivo obter informações sobre nidificação desses insetos em áreas de Floresta Decidual. O trabalho fo i realizado no estado de Minas Gerais, Brasil, no período de junho de 2014 a abril de 2015. Foram registradas  128  colônias  de  19  espécies  distribuídas  em 12  gêneros de    vespas    sociais nidificadas  em  30  famílias  vegetais.  As vespas sociais se comportam como  generalista em relação  à escolha do  substrato  vegetal para nidificação corroborando com dados registrados em outros ecossistemas.