Various organisms emit malodorous secretions against competitors, and the potential use of these secretions in pest management should be investigated. For example, some ant species feed on similar ...resources as dung beetles, which might have led to counter chemical defences in dung beetles. We tested whether pygidial secretions of the dung beetle Canthon smaragdulus (Fabricius) (Coleoptera: Scarabaeidae, Scarabaeinae) alter the locomotor behaviour of the exotic urban pest ant Tapinoma melanocephalum (Fabricius) (Hymenoptera: Formicidae), specifically whether these secretions repel those ants. We also tested whether the disturbance in the locomotor behaviour of T. melanocephalum increases with the amount of pygidial secretion. We found that individual T. melanocephalum displayed changes in their locomotor behaviour when exposed to pygidial secretions of coupled dung beetles, single males, and single females. Additionally, the pygidial secretions from male and female dung beetles could repel ants. The change in the locomotor behaviour of T. melanocephalum increased with the amount of pygidial secretion. Our results suggest that the pygidial secretions of dung beetles have potential as a biological repellent of T. melanocephalum. Hence, pygidial secretions from dung beetles may be used in the future for the development of urban pest management strategies.
We tested whether pygidial secretions of the dung beetle Canthon smaragdulus (Coleoptera: Scarabaeidae) could work as repellents against the exotic urban pest ant Tapinoma melanocephalum (Hymenoptera: Formicidae). The locomotor behaviour of individual ants was affected by pygidial secretions from C. smaragdulus males, females, or male‐female couples. Female secretions had a stronger effect than male secretions, and the changes in locomotor behaviour were dose dependent. Hence, pygidial secretions from dung beetles may be explored further in future urban pest management strategies.
•We evaluate if Eucalyptus plantations are novel or hybrid ecosystems.•We compare biotic and abiotic components among the ecosystems evaluated.•Eucalyptus plantations are hybrid ecosystems.•Proper ...management of this system might improve its conservation value.•Modified ecosystems present different potential for biodiversity conservation.
Novel and hybrid ecosystems present different conservation values for native species. Therefore, the classification of modified ecosystems into a novel or hybrid state is an essential step to assist conservation strategies for biodiversity. During the last decades, plantations of Eucalyptus have increased in the highly threatened Atlantic Forest region, highlighting the importance of defining this ecosystem as novel or hybrid. In this study, we evaluated whether Eucalyptus plantations are novel or hybrid ecosystems by contrasting biotic components (dung beetle communities) and abiotic components (local environmental variables) within historical (Atlantic Forest remnants) and non-historical (pasture) environments in the Atlantic Forest biome, located in Bahia state, Brazil. Our results show that Eucalyptus plantations should be classified and managed as a hybrid ecosystem in this biome. Of the 21 dung beetle species found in Eucalyptus, ten were shared with historical forests (52.6% of Eucalyptus species) and 6 with pastures (31.5%). Eucalyptus plantations have environmental aspects similar to both historical forests and pastures. Despite presenting similar components to historical and non-historical ecosystems, Eucalyptus plantations are sufficiently distinct not to be classified as either one of them. Our results highlight the potential conservation value of Eucalyptus plantations in the Atlantic Forest region as complementary habitat for historical species, and we discuss how alternative management at landscape and stand (local) scales might increase this value. Although dung beetles are an excellent group to monitor biodiversity, we reinforce the necessity to perform further studies using another taxon that present different ecosystem requirements.
We analyzed arthropod community structure and composition among different anthropogenic systems. The study was conducted in areas of secondary forest (control system), Eucalyptus plantation and ...pasture, where we sampled arthropods using pitfall traps. The systems did not differ in mean richness and mean abundance of arthropods, however, eucalyptus presented the highest total richness. The systems supported different arthropod communities in relation to structure and species composition. Pasture was the most simplified and different system in comparison to the others, probably because it is more open and presents low complexity. Our results demonstrate that different anthropogenic systems exhibit communities that reflect its characteristics, corroborating the evidence that human impacts are capable of changing community composition and structure. Our study serves to understand arthropod response in face of environmental disturbance, selecting indicator morphospecies and orders of arthropods for different anthropogenic systems and providing valid information for the development of conservation strategies.
This study provides data about the Scarabaeinae fauna that occurs in a eucalyptus plantation inserted in an originally open area, describing which are able to establish themselves in this introduced ...and shaded environment. The survey was carried in an area of eucalyptus monoculture using flight intercept and pitfall traps baited with human feces, rotten banana and carcass, from December 2005 to November 2006. Twenty-eight species were collected, belonging to 11 genera. Of these 28 species, 11 have been previously recorded in grassland and native forest environments of the region, 11 only in grasslands, two were exclusive of eucalyptus plantations and four were not identified at the specific level, which did not allow the achievement of more information on these species in the natural ecosystems of the region. The results showed that species that occur in eucalyptus are habitat generalists, have preference for shaded environments and/or are tourist species. This, however, is one of the few surveys performed in the region. Therefore, additional studies are necessary to obtain more information about the distribution and response of dung beetles to natural and anthropogenic ecosystems of the region.Original Abstract: Este estudo disponibiliza dados sobre a fauna de Scarabaeinae que ocorre em plantio de eucalipto inserido em uma area originalmente aberta, citando quais especies conseguem se estabelecer neste ambiente introduzido e sombreado. O levantamento de Scarabaeinae foi realizado em uma area de monocultura de eucalipto com armadilhas de interceptacao de voo e armadilhas de queda iscadas com fezes humanas, banana em decomposicao e carcaca, entre os meses de dezembro de 2005 e novembro de 2006. Foram capturadas 28 especies pertencentes a 11 generos. Destas, 11 ja foram registradas em ambientes de campo e mata nativa da regiao, outras 11 apenas em campo nativo, duas mostraram-se exclusivas ao plantio de eucalipto e quatro nao foram identificadas a nivel especifico, o que nao possibilitou a obtencao de maiores informacoes sobre registros em ecossistemas naturais da regiao. Os resultados obtidos mostraram que as especies que ocorrem em eucalipto sao generalistas em relacao ao habitat, apresentam preferencia por ambientes sombreados e/ou sao especies "turistas". Este, contudo, representa um dos poucos levantamentos realizados na regiao e por isso, novos estudos sao necessarios a fim de obter maiores informacoes acerca da distribuicao e resposta dos escarabeineos aos sistemas naturais e antropizados.
Patterns of diversity and community composition in forests are controlled by a combination of environmental factors, historical events, and stochastic or neutral mechanisms. Each of these processes ...has been linked to forest community assembly, but their combined contributions to alpha and beta-diversity in forests has not been well explored. Here we use variance partitioning to analyze ~40 000 individual trees of 49 species, collected within 137 ha of sampling area spread across a 900-ha temperate deciduous forest reserve in Pennsylvania to ask (1) To what extent is site-to-site variation in species richness and community composition of a temperate forest explained by measured environmental gradients and by spatial descriptors (used here to estimate dispersal-assembly or unmeasured, spatially structured processes)? (2) How does the incorporation of land-use history information increase the importance attributed to deterministic community assembly? and (3) How do the distributions and abundances of individual species within the community correlate with these factors? Environmental variables (i.e., topography, soils, and distance to stream), spatial descriptors (i.e., spatial eigenvectors derived from Cartesian coordinates), and land-use history variables (i.e., land-use type and intensity, forest age, and distance to road), explained about half of the variation in both species richness and community composition. Spatial descriptors explained the most variation, followed by measured environmental variables and then by land-use history. Individual species revealed variable responses to each of these sets of predictor variables. Several species were associated with stream habitats, and others were strictly delimited across opposing north- and south-facing slopes. Several species were also associated with areas that experienced recent (i.e., <100 years) human land-use impacts. These results indicate that deterministic factors, including environmental and land-use history variables, are important drivers of community response. The large amount of "unexplained" variation seen here (about 50%) is commonly observed in other such studies attempting to explain distribution and abundance patterns of plant communities. Determining whether such large fractions of unaccounted for variation are caused by a lack of sufficient data, or are an indication of stochastic features of forest communities globally, will remain an important challenge for ecologists in the future.
A kinetic model describing Fenton and photo-Fenton degradation of paracetamol (PCT) and consumption of hydrogen peroxide (H
2
O
2
) was proposed. A set of Fenton and photo-Fenton experiments (18 runs ...in total) was performed by fixing the initial concentration of PCT to 40 mg L
−1
and varying the initial concentrations of H
2
O
2
and ferrous ion, Fe
2+
. The experimental set-up was a well-stirred annular photoreactor equipped with an actinic BL TL-DK 36 W/10 1SL lamp. Experimental results highlighted that PCT is no more detected by HPLC analysis within a minimum reaction time of 2.5 and a maximum reaction time of 15.0 min. Besides, a maximum conversion of total organic carbon (TOC) of 68.5% was observed after 75 min of reaction in case of using UV radiation and the highest concentrations of the Fenton reagents. The experimental data were used to fit the kinetic model. The radiation field inside the reactor was taken into account through the local volumetric rate of photon absorption, evaluated by assuming a line source model with spherical and isotropic emission. The kinetic parameters were estimated by using a non-linear least-squares regression procedure and root mean square errors (RMSE) were calculated in order to validate the feasibility of the proposed model. A good agreement between experimental and predicted data was observed and the lowest values of RMSE resulted in 5.84 and 9.59% for PCT and H
2
O
2
normalized concentrations, respectively.
(L.) (Diptera: Culicidae) is one of the main vectors of arboviruses, including dengue, Zika, and chikungunya. It almost exclusively inhabits urban areas. Both sexes feed on plant carbohydrates, ...although for males, this is their only food source. In the case of floral nectars, mosquitoes locate plant sugar sources assisted by volatile compounds. In this work, we found that the floral scent of
elicited a behavioral response in males; therefore, we focused on identifying the volatiles emitted by these flowers. The terpenes (±)-α-pinene, β-pinene, sabinene, and phellandrene and 1-alkenes 1-undecene, and 1-nonene were identified. To determine which compounds are bioactive, pure synthetic lures were assessed using an olfactometer. Only the main compound 1-nonene was an attractant for males. Since our goal was the introduction of synthetic floral-based attractants in toxic sugar-baited traps, we formulated 1-nonene in solid paraffin and stearin matrices to obtain a controlled release system. The bioassay with a toxicological end point showed that the incorporation of a feeding attractant to the toxic sugar trap increased overall mortality. These results suggest that it is possible to use plant volatile compounds or flower cuttings as male
attractants to improve the efficacy of baited traps.
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