The impact of agricultural colonization and deforestation on stingless bee (Apidae: Meliponini) composition and richness in Rondônia, Brazil

Stingless bees were collected throughout the state of Rondônia in the southwestern Brazilian Amazon for 1 year. The impact of agricultural colonization and subsequent deforestation on species composition and richness is explored. Deforestation, around each of 187 sample sites, was characterized at the mesoscale, microscale, and local spatial scale. At the microscale, deforestation was measured using a data layer generated by satellite remote sensing and analyzed with the assistance of a geographic information system. We report perhaps the greatest richness of stingless bees ever recorded in the Tropics, collecting 9,555 individuals from 98 species of stingless bees. Ten of these are new species and 16 were first-ever records for Rondônia. Five new species were scientifically described from the study. We report statistical relationships between deforestation and species richness at all spatial scales of analysis, and we tentatively identify species that appear to be especially sensitive to deforestation. © 2013 INRA, DIB and Springer-Verlag France

Determinants of Spatial Distribution in a Bee Community: Nesting Resources, Flower Resources, and Body Size

Understanding biodiversity distribution is a primary goal of community ecology. At a landscape scale, bee communities are affected by habitat composition, anthropogenic land use, and fragmentation. However, little information is available on local-scale spatial distribution of bee communities within habitats that are uniform at the landscape scale. We studied a bee community along with floral and nesting resources over a 32 km2 area of uninterrupted Mediterranean scrubland. Our objectives were (i) to analyze floral and nesting resource composition at the habitat scale. We ask whether these resources follow a geographical pattern across the scrubland at bee-foraging relevant distances; (ii) to analyze the distribution of bee composition across the scrubland. Bees being highly mobile organisms, we ask whether bee composition shows a homogeneous distribution or else varies spatially. If so, we ask whether this variation is irregular or follows a geographical pattern and whether bees respond primarily to flower or to nesting resources; and (iii) to establish whether body size influences the response to local resource availability and ultimately spatial distribution. We obtained 6580 specimens belonging to 98 species. Despite bee mobility and the absence of environmental barriers, our bee community shows a clear geographical pattern. This pattern is mostly attributable to heterogeneous distribution of small (<55 mg) species (with presumed smaller foraging ranges), and is mostly explained by flower resources rather than nesting substrates. Even then, a large proportion (54.8%) of spatial variability remains unexplained by flower or nesting resources. We conclude that bee communities are strongly conditioned by local effects and may exhibit spatial heterogeneity patterns at a scale as low as 500-1000 m in patches of homogeneous habitat. These results have important implications for local pollination dynamics and spatial variation of plant-pollinator networks

Effects of habitat type change on taxonomic and functional composition of orchid bees (Apidae: Euglossini) in the Brazilian Amazon

© 2018, Springer International Publishing AG, part of Springer Nature. Land use change impact species richness and functional diversity (FD). In the Brazilian Amazon, we examined the impacts of oil palm plantations on orchid bee (Apidae: Euglossini) species using abundance and FD. We collected male orchid bees in oil palm plantation (PALM), legal reserves (LR), and riparian corridors (APP), and then we used morphological and life-history traits to characterize each species. We evaluated differences in bee body size by comparing intertegular span values. We tested the influence of habitat on taxonomic and functional parameters of orchid bees by applying a partial redundancy analysis (pRDA). We contrasted FD by calculating species richness, functional richness, and functional dispersion. We sampled 1176 bees from 30 species in 18 sampling days across 2015 and 2016. Males from PALM were 13.6% bigger than those in LR areas, and bees from APP showed a similar pattern compared to LR and PALM. Less than 15% of the variation in species composition was related to the distance among sampling sites, and 8% was due to habitat structure. In our pRDA, the spatial difference explained 6% of the variation in orchid bee traits, but there were no effects of habitat parameters upon FD. FD was reduced with land use change caused by oil palm plantations. Our findings support the belief that many bees are impacted by cultivated lands. Nevertheless, the functional similarity between LRs and APPs reflects common structural elements between them, although we did not find significant relationship between functional composition and habitat structure that we evaluated

EPR on Flavoproteins

Flavoproteins often employ radical mechanisms in their enzymatic reactions. This involves paramagnetic species, which can ideally be investigated with electron paramagnetic resonance (EPR) spectroscopy. In this chapter we focus on the example of flavin-based photoreceptors and discuss, how different EPR methods have been used to extract information about the flavin radical’s electronic state, its binding pocket, electron-transfer pathways, and about the protein’s tertiary and quaternary structure

Root inoculation of strawberry with the entomopathogenic fungi Metarhizium robertsii and Beauveria bassiana reduces incidence of the twospotted spider mite and selected insect pests and plant diseases in the field

The effect of inoculation of strawberry roots by two entomopathogenic fungal isolates, Metarhizium robertsii (ESALQ 1622) and Beauveria bassiana (ESALQ 3375), on naturally occurring arthropod pests and plant diseases was investigated in four commercial strawberry fields during two growing seasons in Brazil. Three locations represented open-field production while strawberries were grown in low tunnels at the fourth location. Population responses of predatory mites to the fungal treatments were also assessed. Plants inoculated by the fungal isolates resulted in significantly fewer Tetranychus urticae adults compared to control plants at all four locations. The mean cumulative numbers ± SE of T. urticae per leaflet were: M. robertsii (225.6 ± 59.32), B. bassiana (206.5 ± 51.48) and control (534.1 ± 115.55) at the three open-field locations, while at the location with tunnels numbers were: M. robertsii (79.7 ± 10.02), B. bassiana (107.7 ± 26.85) and control (207.4 ± 49.90). Plants treated with B. bassiana had 50% fewer leaves damaged by Coleoptera, while there were no effects on numbers of whiteflies and thrips. Further, lower proportions of leaflets with symptoms of the foliar plant pathogenic fungi Mycosphaerella fragariae and Pestalotia longisetula were observed in the M. robertsii (4.6% and 1.3%)- and B. bassiana (6.1% and 1.3%)-treated plots compared to control plots (9.8% and 3.7%). No effect was seen on numbers of naturally occurring predatory mites. Our results suggest that both isolates tested may be used as root inoculants of strawberries to protect against foliar pests, particularly spider mites, and also against foliar plant pathogenic fungi without harming naturally occurring and beneficial predatory mites.acceptedVersio