Activity time of male Euglossina and preference for artificial fragrances in forest and dunes in the Environmental Protection Area of the Mamanguape River Bar, Rio Tinto, Paraíba, Brazil

Euglossina bees form a group with about 200 species known, widespread in Neotropical Region. Males collect aromatic compounds on flowers and by using synthesized analogs it is possible to accomplish faunistic inventories and study several ecological aspects of these bees. In this work we studied the activity hours and the preference of aromatic compounds by Euglossina males in forest and dunes at Environmental Protection Area of the Mamanguape River Bar, Rio Tinto, Paraíba State, between August 2002 and July 2004. Six artificial compounds were used as attractive: benzyl acetate, ionone beta, skatole, eucalyptol, eugenol and vanillin. Nine species were sampled, being two of them exclusive of the forest. Euglossa cordata (L.) and Eulaema nigrita Lepeletier were the most abundant species as in the forest as on dunes. Males were more active between 8:00 a.m. and 10:00 a.m. in both areas, with no variation throughout the year. Eucalyptol and eugenol attracted most number of species. E. cordata demonstrated preference by ionone beta and eucalyptol and E. nigrita by skatole and eucalyptol.     

Interaction of the temperature with the parasite mite Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) on the development of Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae)

The objective of this study was to evaluate the effect of different temperatures with the association of the mite Acarophenax lacunatus (Cross & Krantz) on the population suppression of Rhyzopertha dominica (Fabricius). The experimental units were petri dishes containing 40 g of whole wheat grains (13% moisture content) infested with 10 adults of R. dominica, under the temperatures of 20, 25, 30 and 35 masculineC, with or without A. lacunatus, in five replicates. Relative humidity of 60 +/- 5% and escotophase of 24h were used for all temperatures. Five days after the infestation, five mites were inoculated in each experimental unit. The evaluations were carried out at 20, 40, 60, 80, 100 and 120 days after R. dominica infestation. The interaction of the temperature with the parasite A. lacunatus was an important tool for the population suppression of R. dominica. In temperatures higher than 25 masculineC, however, despite the reduction of the immature stages of R. dominica, there was a high grain weight loss after 120 days. The maintenance of the temperature of the wheat grains stored at 20 masculineC can be used to complement the biological control of R. dominica with A. lacunatus.     

Biological hydroperoxides and singlet molecular oxygen generation

The decomposition of lipid hydroperoxides (LOOH) into peroxyl radicals is a potential source of singlet molecular oxygen ((1)O(2)) in biological systems. Recently, we have clearly demonstrated the generation of (1)O(2) in the reaction of lipid hydroperoxides with biologically important oxidants such as metal ions, peroxynitrite and hypochlorous acid. The approach used to unequivocally demonstrate the generation of (1)O(2) in these reactions was the use of an isotopic labeled hydroperoxide, the (18)O-labeled linoleic acid hydroperoxide, the detection of labeled compounds by HPLC coupled to tandem mass spectrometry (HPLC-MS/MS) and the direct spectroscopic detection and characterization of (1)O(2) light emission. Using this approach we have observed the formation of (18)O-labeled (1)O(2) by chemical trapping of (1)O(2) with anthracene derivatives and detection of the corresponding labeled endoperoxide by HPLC-MS/MS. The generation of (1)O(2) was also demonstrated by direct spectral characterization of (1)O(2) monomol light emission in the near-infrared region (lambda = 1270 nm). In summary, our studies demonstrated that LOOH can originate (1)O(2). The experimental evidences indicate that (1)O(2) is generated at a yield close to 10% by the Russell mechanism, where a linear tetraoxide intermediate is formed in the combination of two peroxyl radicals. In addition to LOOH, other biological hydroperoxides, including hydroperoxides formed in proteins and nucleic acids, may also participate in reactions leading to the generation (1)O(2). This hypothesis is currently being investigated in our laboratory.     

Biology of Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) on Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae)

The aim of the present study was to assess the effect of six different temperatures on the development of Acarophenax lacunatus (Cross & Krantz) using eggs of Tribolium castaneum (Herbst) and Cryptolestes ferrugineus (Stephens) as hosts. The temperature affected the development of A. lacunatus. The largest values for the progeny (19 mites in T. castaneum and 15 mites in C. ferrugineus) were obtained at about 30 degrees C, as also observed for the net reproductive rate (Ro), which revealed that the A. lacunatus population increased 18 times in T. castaneum and 14 times in C. ferrugineus in a generation. The intrinsic rate of increase (r m) gradually increased with temperature, reaching the maximum value at 35 degrees C in T. castaneum (1,608) and C. ferrugineus (1,289). The generation time was negatively correlated with temperature, ranging from 1,60 to 4,85 days in T. castaneum and from 1,96 to 5,34 days in C. ferrugineus. These results suggest that the mite A. lacunatus may be used in programs of biological control of T. castaneum and C. ferrugineus in the tropics.     

Utilization of floral resources by bees of the genus Frieseomelitta von Ihering (Hymenoptera: Apidae)

The present study intended to verify which factors (phylogenetic relationship or local ecological conditions) would determine how Frieseomelitta bees use floral resources. The data obtained in the literature on biocenotic studies of Apoidea visiting flowers in Brazil were analyzed, with identification and quantification of floral resources used by Frieseomelitta species in different areas. The phenogram of similarity on use of resources among Frieseomelitta species was compared to the phylogenetic hypothesis proposed for the group. Among the eight Frieseomelitta species registered in 19 studies, F. doederleini (Friese), F. francoi (Moure), F. languida Moure, F. varia (Lepeletier) e Frieseomelitta sp. nov., were collected using resources from 36 plant families. F. doederleini, F. languida e F. varia centralized their activity in Caesalpiniaceae, Malpighiaceae e Anacardiaceae. The similarities and disparities found among areas and Frieseomelitta species reflected the similarities and differences of the vegetation composition in each area. Frieseomelitta bees presented a forage pattern similar to that one presented by other highly social bees, visiting flowers of many plant species, but concentrating their activities in few plant species. Despite the low phylogenetic relationship between F. languida and F. doederleini, they showed a high similarity on the use of floral resource, while F. varia e F. languida, species with high phylogenetic relationship, showed low similarity in the use of resource. Although the data obtained are not conclusive, it indicates that phylogenetic restrictions do not influence the pattern of use of floral resource by Frieseomelitta bees.     

Mites (Acari: Arachnida) associated with Bauhinia variegata L. (Leguminosae) in northeast of State of São Paulo, Brazil

The occurrence of mites on Bauhinia variegata L., a species introduced in Brazil as ornamental, was studied. Two plants of this species were sampled monthly from May 2000 to April 2001. A total of 8,482 mites, belonging to 25 species in 11 families were collected. The abundance of phytophagous mites was higher, being Lorryia formosa Cooreman the dominant species. The dominance of L. formosa might be caused by stress conditions of sampled plants and low number of predaceous mites on those plants.     

Congruence and responsiveness in the taxonomic compositions of Amazonian aquatic macroinvertebrate and fish assemblages

Hydrobiologia - Stream degradation in Amazonia is outpacing our ability to effectively monitor it for three key reasons: (1) Many changes are cumulative and occur gradually; (2) Scientists have...     

Multilocus phylogeography of the endemic and endangered angular angelshark (Squatina guggenheim) in the Southwest Atlantic Ocean

Hydrobiologia - The angular angelshark (Squatina guggenheim) is a coastal endangered angel shark from the Southwest Atlantic Ocean and one of the major bycatch victims. Despite major concerns about...     

Effect of the microbial conditioning and temperature increase on the leaf consumption by shredders in Amazonian aquatic systems

Hydrobiologia - We used experimental chambers to evaluate the effect of the temperature increasing and microbial conditioning degree on the survival and leaf consumption of two plant species...     

Silicon fertigation with appropriate source reduces water requirement of maize under water deficit

Plant and Soil - The objective was to evaluate soluble sources of silicon (Si) applied through fertigation in mitigating water deficit in maize plants. Another objective was to determine the...