Insect artificial diets are not only an important tool for mass rearing, nutritional research, and maintaining laboratory colonies but also for studying insect‐plant interactions. For herbivorous ...insects able to sequester plant toxins, feeding and sequestration assays based on artificial diet allow for the investigation of physiological, ecological, and evolutionary questions which may be difficult to study using real plants representing complex chemical environments. We developed a simple artificial diet, consisting of sunflower meal pressed into pills, for the milkweed bugs Oncopeltus fasciatus (Dallas) and Spilostethus saxatilis (Scopoli) (Heteroptera: Lygaeidae), which are capable of sequestering cardenolides and colchicum alkaloids, respectively. We assessed insect performance, suitability of the diet for sequestration assays, and its shelf life. Compared to sunflower seeds which are widely used as a laboratory maintenance diet for milkweed bugs, no differences were found in terms of weight development, presence of deformities, speed of development, or mortality. Importantly, after feeding O. fasciatus and S. saxatilis sunflower pills enriched with crystalline ouabain (cardenolide) or colchicine (colchicum alkaloid), respectively, sequestration was observed in both species. Moreover, as a prerequisite to test ecological hypotheses, our method allows for adequate concentration control and homogenous distribution of toxins across the diet. Under relatively warm conditions (27 °C and 60% r.h.), the new diet was stable for up to 10 days when used for feeding assays with adult bugs. Therefore, studies focusing on the role of plant toxins in predator–prey interactions and plant defense, but also insecticide research could benefit from using this approach.
We developed a simple artificial diet consisting of sunflower meal pressed into pills for the milkweed bugs Oncopeltus fasciatus and Spilostethus saxatilis (Heteroptera: Lygaeidae), insects able to sequester plant toxins. Benefits of our diet include its high quality as a dietary resource, its suitability for sequestration experiments, and its shelf life to carry out short‐term feeding assays. Studies focusing on the role of plant toxins in predator–prey interactions and plant defense, but also insecticide research could benefit from its use.
Key Message
The aerenchyma in the stem bark of mangroves allows a gas flow pathway outside the xylem, mainly in the lower stem, as the aerenchyma is similar to aerial roots.
Mangroves have developed ...a network of gas spaces in aerenchyma tissue to allow an internal pathway for gas flow into the roots. The presence of aerenchyma in the stem bark of
Rhizophora mangle
and
Avicennia germinans
suggests that air might flow through this tissue external to the xylem. The structure of
R. mangle
and
A. germinans
stem bark aerenchyma and the air volumetric flow rate (
Q
) among aerial roots and two different levels in the stem were compared. Samples of the bark and aerenchyma traits were analyzed using light microscopy, scanning electron microscopy (SEM), and resin casts. Hypertrophy in lenticels widened their opening. In
A. germinans
, there were interconnected canal segments with a straight and parallel pattern in the upper part of the stem and curvatures in the lower level. In
R. mangle
, the canals were more extended. Both species contained honeycomb-like aerenchyma in the lower level of the stem, contributing to canal structures' resistance to internal pressure. Both species had phi thickening in the radial walls, and
R. mangle
H-trichosclereids supporting the canal structures may resist internal pressure. The lysis of cortical cells contributed to canal formation in the lower stem of
A. germinans
. The shape and length of the aerenchyma longitudinal canals were determined mainly by the species. There was a more significant effect of stem level and roots on traits related to intercellular spaces in aerenchyma and lenticel openings. Mangrove species share common functional adaptations and have developed distinctive structural features that allow them to live in a temporary anaerobic root environment.
Abstract
Context
Diabetes and hypertension are frequent comorbidities of acromegaly.
Objective
To analyze the course of diabetes and hypertension at diagnosis and after multimodal therapy in a large ...cohort of patients with acromegaly.
Design and Setting
Retrospective study at a tertiary care center.
Patients and Methods
A total of 522 patients with acromegaly treated according to a preestablished protocol.
Main Outcome Measures
Prevalence of diabetes and hypertension and its relationship with biochemical indices of acromegalic control.
Results
The cohort was stratified according to disease activity upon last visit to clinic: (1) surgical remission (n = 122), (2) pharmacologically controlled (n = 92), (3) active disease (n = 148), (4) insulinlike growth factor (IGF)-1 discordance (n = 64), and (5) growth hormone (GH) discordance (n = 96). The prevalence of diabetes and hypertension at diagnosis was 30% and 37%, respectively, and did not change upon the last visit (30.6% and 38%). Both comorbidities were more prevalent at diagnosis and on the last visit than in the general population. Diabetes was less prevalent on the last visit in patients who achieved surgical remission than in those who persisted with active disease (25% vs 40%, P = 0.01). Upon multivariate analysis, diabetes was associated with an IGF-1 at diagnosis >2× upper limit of normal, with the persistence of active acromegaly, the presence of hypertension upon the last visit, with the presence of a macroadenoma, and with female sex.
Conclusion
Our findings underscore the importance of an integral approach when managing these patients, focusing not only on the control of GH and IGF-1 levels but also on the timely diagnosis and the specific treatment of each comorbidity.
The prevalence of diabetes and hypertension was analyzed in 522 patients with acromegaly at diagnosis and after therapy. Both were equally prevalent at diagnosis and upon last visit.
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► We tested honey bee genotypes for grooming behavior and varroa mite resistance. ► Grooming behavior is an important component in the resistance of honey bees to varroa mites. ► The ...intensity with which bees perform it increases the proportion of mite removal.
The objective of this study was to demonstrate genotypic variability and analyze the relationships between the infestation levels of the parasitic mite Varroa destructor in honey bee (Apis mellifera) colonies, the rate of damage of fallen mites, and the intensity with which bees of different genotypes groom themselves to remove mites from their bodies. Sets of paired genotypes that are presumably susceptible and resistant to the varroa mite were compared at the colony level for number of mites falling on sticky papers and for proportion of damaged mites. They were also compared at the individual level for intensity of grooming and mite removal success. Bees from the “resistant” colonies had lower mite population rates (up to 15 fold) and higher percentages of damaged mites (up to 9 fold) than bees from the “susceptible” genotypes. At the individual level, bees from the “resistant” genotypes performed significantly more instances of intense grooming (up to 4 fold), and a significantly higher number of mites were dislodged from the bees’ bodies by intense grooming than by light grooming (up to 7 fold) in all genotypes. The odds of mite removal were high and significant for all “resistant” genotypes when compared with the “susceptible” genotypes. The results of this study strongly suggest that grooming behavior and the intensity with which bees perform it, is an important component in the resistance of some honey bee genotypes to the growth of varroa mite populations. The implications of these results are discussed.
Infectious disease threat events (IDTEs) are increasing in frequency worldwide. We analyzed underlying drivers of 116 IDTEs detected in Europe during 2008-2013 by epidemic intelligence at the ...European Centre of Disease Prevention and Control. Seventeen drivers were identified and categorized into 3 groups: globalization and environment, sociodemographic, and public health systems. A combination of >= 2 drivers was responsible for most IDTEs. The driver category globalization and environment contributed to 61% of individual IDTEs, and the top 5 individual drivers of all IDTEs were travel and tourism, food and water quality, natural environment, global trade, and climate. Hierarchical cluster analysis of all drivers identified travel and tourism as a distinctly separate driver. Monitoring and modeling such disease drivers can help anticipate future IDTEs and strengthen control measures. More important, intervening directly on these underlying drivers can diminish the likelihood of the occurrence of an IDTE and reduce the associated human and economic costs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Although mangrove forests are great carbon sinks, they also release carbon dioxide (CO2) from soil, plants, and water through respiration. Many studies have focused on CO2 effluxes only from soils, ...but the role of biogenic structures such as pneumatophore roots has been poorly studied. Hence, CO2 effluxes from pneumatophores were quantified at sediment-air (non-flooded sediment) and water–air (flooded sediment) interfaces along a salinity gradient in three mangrove types (fringe, scrub, and basin) dominated by Avicennia germinans during the dry and rainy seasons in Yucatan, Mexico. Pneumatophore abundance explained up to 91% of CO2 effluxes for scrub, 87% for fringe, and 83% for basin mangrove forests at the water–air interface. Overall, CO2 effluxes were inversely correlated with temperature and salinity. The highest CO2 effluxes were in the fringe and the lowest were in the scrub mangrove forests. Flooding decreased CO2 effluxes from the dry to the rainy season in all mangrove forests. These results highlight the contribution of pneumatophores to mangrove respiration, and the need to include them in our current carbon budgets and models, but considering different exchange interfaces, seasons, and mangrove ecotypes.
ABSTRACTAlthough critical studies on peace and conflict studies have addressed the topic of knowledge production and peacebuilding, this is not a highly discussed issue in the literature. There is no ...unique or unambiguous conceptual framework to analyze this topic. This article shows conceptual elements that must be considered to understand the interaction between local and scientific knowledge in research projects on peace and peacebuilding; and reflects on what types of problems emerge when local and expert knowledge interact within the context of international cooperation projects. Based on the evidence collected during one workshop with Colombian researchers and the analysis of fifty research proposals funded by the German Colombian Peace Institute (CAPAZ) between 2017 and 2021, this article identifies topics, methodologies and products that suggest the existence of hybridization and co-production practices of knowledge when research on peacebuilding and conflict is designed and conceived.
Recruitment from seeds is among the most vulnerable stage for plants as global temperatures change. While germination is the means by which the vast majority of the world's flora regenerate ...naturally, a framework for accurately predicting which species are at greatest risk of germination failure during environmental perturbation is lacking. Taking a physiological approach, we assess how one family, the Cactaceae, may respond to global temperature change based on the thermal buffering capacity of the germination phenotype. We selected 55 cactus species from the Americas, all geo‐referenced seed collections, reflecting the broad environmental envelope of the family across 70° of latitude and 3700 m of altitude. We then generated empirical data of the thermal germination response from which we estimated the minimum (Tb), optimum (To) and ceiling (Tc) temperature for germination and the thermal time (θ50) for each species based on the linearity of germination rate with temperature. Species with the highest Tb and lowest Tc germinated fastest, and the interspecific sensitivity of the germination rate to temperature, as assessed through θ50, varied tenfold. A left‐skewed asymmetry in the germination rate with temperature was relatively common but the unimodal pattern typical of crop species failed for nearly half of the species due to insensitivity to temperature change at To. For 32 fully characterized species, seed thermal parameters correlated strongly with the mean temperature of the wettest quarter of the seed collection sites. By projecting the mean temperature of the wettest quarter under two climate change scenarios, we predict under the least conservative scenario (+3.7°C) that 25% of cactus species will have reduced germination performance, whilst the remainder will have an efficiency gain, by the end of the 21st century.
Predictions of germination performance were made by comparing the optimum germination temperature (To) with current and projected climate change scenarios (+1.0°C and +3.7°C); a negative impact on germination rate is predicted when the environmental temperature exceeds To (a). The time required to achieve 50% germination under the different scenarios was also calculated (b). Under the +3.7°C scenario, 24 species will have an efficiency gain in germination demonstrating sufficient thermal buffering to cope with global temperature change.
Grooming behavior confers resistance to honey bees against the mite
Varroa destructor
and thus is a mechanism of interest for studies of social immunity and breeding purposes. However, mites are not ...always available to conduct grooming assays and can introduce variability to the evaluations. Therefore, the objective of this study was to evaluate the use of wheat flour as an irritant in a laboratory assay to assess self-grooming behavior in honey bees. Presumed
Varroa
-susceptible and
Varroa-
resistant genotypes were used to determine the time it took the bees to initiate grooming instances and the proportion of bees that responded when exposed to either flour or a
Varroa
mite. Flour elicited significantly faster grooming responses and with a higher proportion of individuals in both genotypes in comparison with
V. destructor
. Also, significant differences between both genotypes were observed. It is concluded that flour can be used as an irritant instead of
V. destructor
to evaluate self-grooming behavior in bees in the laboratory.
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•Varroa destructor parasitism and DWV kill developing Africanized bees.•Varroa destructor parasitism and DWV inhibit immunity in developing Africanized bees.•Varroa destructor ...parasitism and DWV cause deformities in wings of Africanized bees.•Varroa destructor parasitism and DWV shorten the lifespan of adult Africanized bees.•Africanized bee tolerance to V. destructor might not reside in brood-related mechanisms.
The ectoparasitic mite Varroa destructor is the primary health problem of honey bees (Apis mellifera) worldwide. Africanized honey bees in Brazil have demonstrated tolerance to the mite, but there is controversy about the degree of mite tolerance of Africanized bees in other countries. This study was conducted to quantify the effect of V. destructor parasitism on emergence, hemocyte concentration, wing integrity and longevity of Africanized honey bees in Mexico. Africanized bee brood were artificially infested with V. destructor mites and held in an incubator until emergence as adults and compared to non-infested controls. Deformed wing virus (DWV) presence was determined in the mites used to infest the bees. After emergence, the bees were maintained in an incubator to determine survivorship. The percentage of worker bees that emerged from parasitized cells (69%) was significantly lower than that of bees emerged from non-infested cells (96%). Newly-emerged parasitized bees had a significantly lower concentration of hemocytes in the hemolymph than non-parasitized bees. Additionally, the proportion of bees with deformed wings that emerged from V. destructor-parasitized cells was significantly higher (54%) than that of the control group (0%). The mean survival time of bees that emerged from infested and non-infested cells was 8.5 ± 0.3 and 14.4 ± 0.4 days, respectively, and the difference was significant. We conclude that V. destructor parasitism and DWV infections kill, cause deformities and inhibit cellular immunity in developing Africanized honey bees, and significantly reduce the lifespan of adult bees in Mexico. These results suggest that the tolerance of Africanized bees to V. destructor is related to adult bee mechanisms.
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