It is hot and cold here: the role of thermotolerance in the ability of spiders to colonize tree plantations in the southern Atlantic Forest.

Worldwide, with the decline of natural habitats, species with reduced niche breadth (specialists) are at greater risk of extinction as they cannot colonise or persist in disturbed habitat types. However, the role of thermal tolerance as a critical trait in understanding changes in species diversity in disturbed habitats, e.g.

Challenging Popular Belief, Mosquito Larvae Breathe Underwater.

Immature mosquitoes are thought to breathe only atmospheric air through their siphons despite reports of prolonged submerged survival. We studied the survival of last-instar larvae of fully submerged at different temperatures and measured the oxygen consumption from air and water-dissolved larvae and pupae of this species under different conditions. Larvae survived much longer than expected, reaching 50% mortality only after 58, 10, and 5 days at 15°, 25°, and 35 °C, respectively.

Diatomaceous earth as insecticide: physiological and morphological evidence of its underlying mechanism.

Background: Wheat grain containers or silos can be perfect habitats for insects, which generate large economic losses to grain production. Natural alternatives to synthetic insecticides have grown in popularity because of health, economic and ecological issues. Diatomaceous earth is a natural compound that has an insecticide effect by enhancing an insect's dehydration with no toxicity on mammals including humans.

Effect of brief exposures of anesthesia on thermotolerance and metabolic rate of the spotted-wing fly, Drosophila suzukii: Differences between sexes?

The spotted-wing fly, Drosophila suzukii, is a world-wide pest insect for which there is increasing interest in its physiological traits including metabolism and thermotolerance. Most studies focus only on survival to different time exposures to extreme temperatures, mainly in female flies. In addition, it has not been tested yet how anesthesia affects these measurements.

Machine-learning model led design to experimentally test species thermal limits: The case of kissing bugs (Triatominae).

Species Distribution Modelling (SDM) determines habitat suitability of a species across geographic areas using macro-climatic variables; however, micro-habitats can buffer or exacerbate the influence of macro-climatic variables, requiring links between physiology and species persistence. Experimental approaches linking species physiology to micro-climate are complex, time consuming and expensive. E.

Viscosity as a key factor in decision making of nectar feeding ants.

It is well known that viscosity reduces the intake rates in nectar-feeding insects, such as nectivorous ants, though it remains unclear whether viscosity imposes a higher energy investment in these insects, and how this affects their feeding motivation. To address this issue, we studied feeding behavior, metabolism, and pharyngeal pump activity in the carpenter ant Camponotus mus during ingestion of ad libitum sucrose solutions. In some solutions tylose was added to modify viscosity without changing its sucrose concentration, in a way that allowed comparing: (1) two solutions with the same viscosity and different sucrose concentration (10 T and 50), and (2) two solutions with different viscosity and the same sucrose concentration (50 and 50 T).

Aerobic Metabolism Alterations as an Evidence of Underlying Deltamethrin Resistance Mechanisms in Triatoma infestans (Hemiptera: Reduviidae).

Triatoma infestans (Klug, 1834), the main vector of Chagas disease in Latin America, is regularly controlled by spraying the pyrethroid deltamethrin, to which some populations have developed resistance. The three main mechanisms of resistance are 1) metabolic resistance by overexpression or increased activity of detoxifying enzymes, 2) target site mutations, and 3) cuticle thickening/modification. We use open-flow respirometry to measure real-time H2O loss rate (V˙H2O) and CO2 production rate (V˙CO2), on nymphs from susceptible and resistant populations before and after exposure to the insecticide to understand the underlying mechanisms of resistance in live insects.

Push-pull to manage leaf-cutting ants: an effective strategy in forestry plantations.

Background: Leaf-cutting ants (LCAs) are amongst the most important forestry pests in South America. Currently, their control is carried out almost exclusively through the application of toxic baits of restricted use. Here we evaluate a push-pull strategy (i.

Impact of alkaloids in food consumption, metabolism and survival in a blood-sucking insect.

The sense of taste provides information about the "good" or "bad" quality of a food source, which may be potentially nutritious or toxic. Most alkaloids taste bitter to humans, and because bitter taste is synonymous of noxious food, they are generally rejected. This response may be due to an innate low palatability or due to a malaise that occurs after food ingestion, which could even lead to death.

The Phosphatase CSW Controls Life Span by Insulin Signaling and Metabolism Throughout Adult Life in .

Noonan syndrome and related disorders are caused by mutations in genes encoding for proteins of the RAS-ERK1/2 signaling pathway, which affect development by enhanced ERK1/2 activity. However, the mutations' effects throughout adult life are unclear. In this study, we identify that the protein most commonly affected in Noonan syndrome, the phosphatase SHP2, known in as (CSW), controls life span, triglyceride levels, and metabolism without affecting ERK signaling pathway.

Thermal Tolerance Plasticity in Chagas Disease Vectors Rhodnius prolixus (Hemiptera: Reduviidae) and Triatoma infestans.

Temperature is recognized as the most influential abiotic factor on the distribution and dispersion of most insect species including Rhodnius prolixus (Stål, 1859) and Triatoma infestans (Klug, 1834), the two most important Chagas disease vectors. Although, these species thermotolerance range is well known their plasticity has never been addressed in these or any other triatomines. Herein, we investigate the effects of acclimation on thermotolerance range and resistance to stressful low temperatures by assessing thermal critical limits and 'chill-coma recovery time' (CCRT), respectively.

Genetic variation for tolerance to high temperatures in a population of .

The range of thermal tolerance is one of the main factors influencing the geographic distribution of species. Climate change projections predict increases in average and extreme temperatures over the coming decades; hence, the ability of living beings to resist these changes will depend on physiological and adaptive responses. On an evolutionary scale, changes will occur as the result of selective pressures on individual heritable differences.

The costs of living in a thermal fluctuating environment for the tropical haematophagous bug, Rhodnius prolixus.

Environmental temperature is an abiotic factor with great influence on biological processes of living beings. Jensen's inequality states that for non-lineal processes, such as most biological phenomena, the effects of thermal fluctuations cannot be predicted from mean constant temperatures. We studied the effect of daily temperature fluctuation (DTF) on Rhodnius prolixus, a model organism in insect physiology, and an important vector of Chagas disease.

Using eco-physiological traits to understand the realized niche: the role of desiccation tolerance in Chagas disease vectors.

Small ectotherms, such as insects, with high surface area-to-volume ratios are usually at risk of dehydration in arid environments. We hypothesize that desiccation tolerance in insects could be reflected in their distribution, which is limited by areas with high relative values of water vapor pressure deficit (VPD) (e.g.

Enhanced fertility and chill tolerance after cold-induced reproductive arrest in females of temperate species of the complex.

Long-term exposure to low temperatures during adult maturation might decrease fertility after cold recovery as a consequence of carry-over effects on reproductive tissues. This pattern should be more pronounced in tropical than in temperate species as protective mechanisms against chilling injuries are expected to be more effective in the latter. We initially determined the lower thermal thresholds to induce ovarian maturation in four closely related species, two inhabiting temperate regions and the other two tropical areas of South America.

Aggregated oviposition in Rhodnius prolixus, sensory cues and physiological consequences.

Females of the haematophagous bug Rhodnius prolixus attach their eggs in clusters on substrates related to their hosts, such as nests or avian feathers. Because the hosts are an enormous food resource as well as potential predators, the choice of the site and pattern of oviposition could have an important adaptive value. Here we investigated proximate and a potential ultimate cause of this aggregated pattern of laid eggs.

Metabolism and gas exchange patterns in Rhodnius prolixus.

Insect's metabolic rate and patterns of gas-exchange varies according to different factors such as: species, activity, mass, and temperature among others. One particular striking pattern of gas-exchange in insects is discontinuous gas-exchange cycles, for which many different hypotheses regarding their evolution have been stated. This article does not pretend to be an extensive review on the subject, rather to focus on the work performed on the haematophagous bug Rhodnius prolixus, a model organism used from the mid XX century until present days, with the great influence of Wigglesworth and his students/collaborator's work.

Metabolism and water loss rate of the haematophagous insect Rhodnius prolixus: effect of starvation and temperature.

Haematophagous insects suffer big changes in water needs under different levels of starvation. Rhodnius prolixus is the most important haematophagous vector of Chagas disease in the north of South America and a model organism in insect physiology. Although there have been some studies on patterns of gas exchange and metabolic rates, there is little information regarding water loss in R.

Effects of temperature on responses to anoxia and oxygen reperfusion in Drosophila melanogaster.

Insects in general, and Drosophila in particular, are much more capable of surviving anoxia than vertebrates, and the mechanisms involved are of considerable biomedical and ecological interest. Temperature is likely to strongly affect both the rates of damage occurring in anoxia and the recovery processes in normoxia, but as yet there is no information on the effect of this crucial variable on recovery rates from anoxia in any animal. We studied the effects of temperature, and thus indirectly of metabolic flux rates, on survival and recovery times of individual male Drosophila melanogaster following anoxia and O(2) reperfusion.

The insulin-regulated CREB coactivator TORC promotes stress resistance in Drosophila.

In fasted mammals, glucose homeostasis is maintained through induction of the cAMP response element-binding protein (CREB) coactivator transducer of regulated CREB activity 2 (TORC2), which stimulates the gluconeogenic program in concert with the forkhead factor FOXO1. Here we show that starvation also triggers TORC activation in Drosophila, where it maintains energy balance through induction of CREB target genes in the brain. TORC mutant flies have reduced glycogen and lipid stores and are sensitive to starvation and oxidative stress.

Oxygen reperfusion damage in an insect.

The deleterious effects of anoxia followed by reperfusion with oxygen in higher animals including mammals are well known. A convenient and genetically well characterized small-animal model that exhibits reproducible, quantifiable oxygen reperfusion damage is currently lacking. Here we describe the dynamics of whole-organism metabolic recovery from anoxia in an insect, Drosophila melanogaster, and report that damage caused by oxygen reperfusion can be quantified in a novel but straightforward way.

Breathe softly, beetle: continuous gas exchange, water loss and the role of the subelytral space in the tenebrionid beetle, Eleodes obscura.

Flightless, diurnal tenebrionid beetles are commonly found in deserts. They possess a curious morphological adaptation, the subelytral cavity (an air space beneath the fused elytra) the function of which is not completely understood. In the tenebrionid beetle Eleodes obscura, we measured abdominal movements within the subelytral cavity, and the activity of the pygidial cleft (which seals or unseals the subelytral cavity), simultaneously with total CO2 release rate and water loss rate.

Haemolymph sugar levels in a nectar-feeding ant: dependence on metabolic expenditure and carbohydrate deprivation.

In nectar-feeding insects, sugars are an important source of fuel and energy storage. Here, we analyzed the haemolymph sugar levels in foragers of the ant Camponotus rufipes trained to collect nectar from an artificial feeder, and their dependence on the metabolic rate during feeding. The main sugar found was trehalose, followed by glucose and traces of fructose and sucrose.