Hotter-is-not-better: A study on the thermal response of a winter active and nocturnal beetle.

While there are numerous examples of thermogenesis processes in poikilothermic insects that maintain a stable temperature for a certain time and in certain parts of the body, there is a lack of information on ectothermic insect species capable of remaining active under "cold" conditions that would be challenging for other species. Such a thermal strategy would imply the existence of a metabolism that can operate at different temperatures without the need to increase body temperature when experiencing cold environmental conditions. This "hotter-is-not-better" thermal strategy is considered ancestral and conjectured to be linked to the origin and evolution of endothermy. In this study, we examined the thermal performance of a large-bodied dung beetle species (Chelotrupes momus) capable of being active during the winter nights in the Iberian Mediterranean region. Field and laboratory results were obtained using thermocamera records, thermocouples, data loggers and spectrometers that measured ultraviolet, visible and near-infrared wavelengths. The thermal data clearly indicated that this species can remain active at a body temperature of approximately 6 °C without the need to warm its body above ambient temperature. Comparing the spectrophotometric data of the species under study with that from other previously examined dung beetle species indicated that the exoskeleton of this particular species likely enhances the absorption of infrared radiation, thereby implying a dual role of the exoskeleton in both heat acquisition and heat dissipation. Taken together, these results suggest that this species has morphological and metabolic adaptations that enable life processes at temperatures that are typically unsuitable for most insect species in the region.

Taking advantage of opportunistically collected historical occurrence data to detect responses to climate change: The case of temperature and Iberian dung beetles.

This study introduces a novel approach to leverage high-resolution historical climate data and opportunistically collected historical species occurrence data for detecting adaptive responses to global change. We applied this procedure to the temperature data and the most comprehensive Iberian dataset of dung beetle occurrences as an illustrative example. To understand how populations of different species are responding, we devised a procedure that compares the temporal trend of spatial and temperature variables at the locations and times of all the occurrence data collection (overall trend) with the specific temporal trends among the occurrences of each species. The prevalence of various species responses is linked to life history or taxonomic characteristics, enabling the identification of key factors influencing the propensity to experience different effects from climate change. Our findings suggest that nearly half of the Iberian dung beetle species may be adversely affected by temperature increases, with a geographic shift being the most common response. The results generated through the proposed methodology should be regarded as preliminary information, serving to formulate hypotheses about the diverse responses of species to climate change and aiding in the selection of candidate species capable of coping with challenges posed by changing temperatures.

Can the spectrophotometric response of the elytra explain environmental preferences? A study in seven Onthophagus species (Coleoptera, Scarabaeidae).

Beetles are the most successful and diversified animal taxa characterized by the possession of an external pair of sclerotized wings (elytra). Managing electromagnetic radiations could be one of the functions of the exoskeleton. We studied the spectrophotometric response to ultraviolet, visible, and near-infrared radiations of the elytra of seven closely related and sympatric Onthophagus species to examine if the environmental preferences of these species could be associated with the spectrophotometric behaviour of their elytra. Our results indicated that sibling species can drastically differ in their environmental preferences but not in their spectrophotometric responses. However, our results corroborated that there are interspecific differences in the spectrophotometric characteristics of the elytra, which are mainly explained by morphological features. Among the examined morphological variables, darkness seems to be especially relevant as it facilitates the absorbance and obstructs the transmittance of visible and near-infrared radiations.

Seasonal variation in the diel activity of a dung beetle assemblage.

The seasonal and diel variations of dung beetle species were studied in an Iberian mid-mountain locality to examine the interaction between these two temporal rhythms. We assume that a seasonal variation in the diel activity would support the notion that both rhythms may assist in achieving a quick and flexible response when the climatic conditions change. Data coming from 4,104 pitfall traps placed during 15 sampling periods and totalling 30 daily sampling cycles were analysed using circular statistics and General Linear Models. A wide variety of seasonal patterns are observed, highlighting those species with a clear unimodal or spring-autumn bimodal seasonal pattern. However, a midday diel pattern is the norm in most of the species, except in the case of those exhibiting a high body weight that prefer dusk or night periods. We hypothesize that most of the dung beetle species fly at noon to promote the passive heating of their muscle activity and minimize the metabolic energy expenditure. Results only partially support the seasonal variation in diel activity. Diel preferences are mainly manifested at the time of the year in which the abundance is greater. Approximately two-thirds of the considered species exhibit a similar diel activity along their seasonal active period. As consequence, a significant portion of the dung beetle species currently inhabiting Mediterranean mid-mountains are not able to use the daily variation in climatic conditions to limit the inconveniences of climate change.

First detection of Gongylonema species in Geotrupes mutator in Europe.

The detection of three Gongylonema sp. infective larvae in two specimens of the dung beetle Geotrupes mutator (Marsham, 1802) from western Spain is reported here for the first time in Europe. Scanning electron microscopy confirmed that the analyzed specimens belong to the genus Gongylonema, but it was not possible to determine the species identity by the lack of morphological information in the literature and because many of the phenotypic characteristics had not yet fully developed at this juvenile stage. Nevertheless, a phylogenetic analysis using amplified cox1 nucleotide sequences has revealed that the studied larvae could be clearly discriminated (< 89% identity) from all the other Gongylonema cox1 sequences available in public genetic databases. While our results are limited by the scarcity of genetic information available for this genus, the possibility that the analyzed specimens might correspond to a new species should not be ruled out, and more studies are needed. The results provided in this report indicate that G. mutator is involved in the transmission cycle of Gongylonema sp. to vertebrates in Europe.

Biomagnification and body distribution of ivermectin in dung beetles.

A terrestrial test system to investigate the biomagnification potential and tissue-specific distribution of ivermectin, a widely used parasiticide, in the non-target dung beetle Thorectes lusitanicus (Jekel) was developed and validated. Biomagnification kinetics of ivermectin in T. lusitanicus was investigated by following uptake, elimination, and distribution of the compound in dung beetles feeding on contaminated faeces. Results showed that ivermectin was biomagnified in adults of T. lusitanicus when exposed to non-lethal doses via food uptake. Ivermectin was quickly transferred from the gut to the haemolymph, generating a biomagnification factor (BMFk) three times higher in the haemolymph than in the gut after an uptake period of 12 days. The fat body appeared to exert a major role on the biomagnification of ivermectin in the insect body, showing a BMFk 1.6 times higher than in the haemolymph. The results of this study highlight that the biomagnification of ivermectin should be investigated from a global dung-based food web perspective and that the use of these antiparasitic substances should be monitored and controlled on a precautionary basis. Thus, we suggest that an additional effort be made in the development of standardised regulatory recommendations to guide biomagnification studies in terrestrial organisms, but also that it is necessary to adapt existing methods to assess the effects of such veterinary medical products.

Visible and near-infrared radiation may be transmitted or absorbed differently by beetle elytra according to habitat preference.

BACKGROUND: The exoskeleton of an insect could be an important factor in the success of its evolutionary process. This reaches its maximum expression in beetles, which constitute the most diversified animal taxon. The involvement in the management of environmental radiation could be one of the most important functions of the exoskeleton due to the passive contributions to the thermoregulation of body temperature. We study whether the elytra of two sympatric and closely related beetle species respond differentially to the radiation of distinct wavelengths in agreement with their ecological preferences. METHODS: Onthophagus coenobita (Herbst) and O. medius (Kugelaan) occupy different habitats and environmental conditions (shaded vs. unshaded from solar radiation). The potential adaptive variations to thermoregulation under these different ecological conditions were studied using the responses of their exoskeletons to radiation of different wavelengths (ultraviolet, visible and near-infrared). For these two species, the amounts of the three wavelengths that were reflected, transmitted or absorbed by the exoskeleton were measured using of a spectrophotometer. In addition, the darkness and thickness of the elytra were examined to determine whether these two features influence the management of radiation by the exoskeleton. RESULTS: Both species differ in the management of visible and near-infrared radiation. In agreement with habitat preferences, the species inhabiting shaded conditions would allow infrared and visible radiation to penetrate the elytra more easily to heat internal body parts, while the elytra of the heliophilous species would have increased absorbance of these same types of radiation. An increase in body size (and therefore in elytron thickness) and the quantity of dark spots may serve as barriers against exogenous heat gain. However, the maintenance of between-species differences independent of the effects of these two morphological features led us to suspect that an unconsidered elytron characteristic may also be affecting these differences. DISCUSSION: The results of the involvement of the exoskeleton thickness and spots in the thermoregulation of insects opens new research lines to obtain a better understanding of the function of the exoskeleton as a passive thermoregulation mechanism in Coleoptera.

Author Correction: First assessment of the comparative toxicity of ivermectin and moxidectin in adult dung beetles: Sub-lethal symptoms and pre-lethal consequences.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

A procedure to assess the spatial variability in the importance of abiotic factors affecting distributions: the case of world freshwater fishes.

Understanding the factors shaping species' distributions is a key longstanding topic in ecology with unresolved issues. The aims were to test whether the relative contribution of abiotic factors that set the geographical range of freshwater fish species may vary spatially and/or may depend on the geographical extent that is being considered. The relative contribution of factors, to discriminate between the conditions prevailing in the area where the species is present and those existing in the considered extent, was estimated with the instability index included in the R package SPEDInstabR. We used 3 different extent sizes: 1) each river basin where the species is present (local); 2) all river basins where the species is present (regional); and 3) the whole Earth (global). We used a data set of 16,543 freshwater fish species with a total of 845,764 geographical records, together with bioclimatic and topographic variables. Factors associated with temperature and altitude show the highest relative contribution to explain the distribution of freshwater fishes at the smaller considered extent. Altitude and a mix of factors associated with temperature and precipitation were more important when using the regional extent. Factors associated with precipitation show the highest contribution when using the global extent. There was also spatial variability in the importance of factors, both between species and within species and from region to region. Factors associated with precipitation show a clear latitudinal trend of decreasing in importance toward the equator.

First assessment of the comparative toxicity of ivermectin and moxidectin in adult dung beetles: Sub-lethal symptoms and pre-lethal consequences.

Among macrocyclic lactones (ML), ivermectin (IVM) and moxidectin (MOX) potentially affect all Ecdysozoan species, with dung beetles being particularly sensitive. The comparative effects of IVM and MOX on adult dung beetles were assessed for the first time to determine both the physiological sub-lethal symptoms and pre-lethal consequences. Inhibition of antennal response and ataxia were tested as two intuitive and ecologically relevant parameters by obtaining the lowest observed effect concentration (LOEC) values and interpolating other relevant toxicity thresholds derived from concentration-response curves (IC50, as the concentration of each ML where the antennal response is inhibited by half; and pLC50, as the quantity of ingested ML where partial paralysis was observed by half of treated individuals) from concentration-response curves. Both sub-lethal and pre-lethal symptoms obtained in this study coincided in that IVM was six times more toxic than MOX for adult dung beetles. Values of LOEC, IC50 and pLC50 obtained for IVM and MOX evaluated in an environmental context indicate that MOX, despite needing more time for tis elimination in the faeces, would be twice as harmful to dung beetles as IVM. This approach will be valuable to clarify the real impact of MLs on dung beetle health and to avoid the subsequent environmental consequences.

Distribution of Canthon rutilans rutilans and Canthon rutilans cyanescens Along Spatio-Temporal and Temperature Gradients.

Subspecies is a debated taxonomic rank that, in some cases, could indicate that a speciation process is taking place. Studying the degree of co-occurrence among subspecies along environmental gradients may help to determine its taxonomic status. In this study, we explore the distribution of two subspecies of Canthon rutilans along spatio-temporal and temperature gradients in the Atlantic Forest of southern Brazil in order to reinforce their current subspecies status or to support their consideration as two different species. A yearly survey conducted along an elevational transect (from 250 m to 1630 m) shows that there is no spatio-temporal overlap between the two taxa. We collected 899 individuals of Canthon rutilans cyanescens and 29 individuals of Canthon rutilans rutilans. C. rutilans cyanescens can be found at 250 m (all year except in June), 430 m (August to April), and 840 m (September to April) in elevation, and when the air temperature oscillates from 15.3 °C to 24.0 °C. C. rutilans rutilans can be found at 1360 m (October to February), 1630 m (January) in elevation, and when the air temperature oscillates from 14.4 °C to 18.6 °C. Furthermore, local temperature data taken during the survey indicates that both subspecies also have a limited overlap in their thermal response curves. All these results suggest that these two taxa could be considered as two different species with dissimilar physiological and ecological requirements probably as a consequence of temperature-mediated divergent adaptation. Further molecular data can confirm or reject this supposition in the near future.

Comparative thermoregulation between different species of dung beetles (Coleoptera: Geotrupinae).

Insects can use thermoregulation to keep their body temperatures within a certain range in response to thermal stress situations. The mechanisms to regulate internal temperature depend on whether species are endothermic or ectothermic species, i.e., if the heat source is internal and/or external. In this study, the thermal stress response due to excess heat was examined in individuals belonging to different species of the Geotrupinae subfamily by using a standardized protocol based on infrared thermography. All the measured heat stress variables allow discrimination among the considered species to a greater or lesser extent. The body heating rate in the heat stress range, the critical thermal maximum and the stress start temperature were the most important variables in discriminating between apterous and winged individuals (R2 = 52.5%, 51.1% and 50.0%, respectively). Examining the degree of association between the physiological similarity of individuals and some species traits suggest that flying capability and daily activity are related with different thermal responses. Based on the obtained results, the Geotrupinae subfamily can be divided into three ecophysiological groups: good, medium and non-thermoregulators. Within these groups, apterism appears mainly in those species with the ability to actively decrease their body temperature. Our results indicate that this ability may be partially due to the management of water loss related with evaporative cooling.

Elytra Absorb Ultraviolet Radiation but Transmit Infrared Radiation in Neotropical Canthon Species (Coleoptera, Scarabaeinae).

Strategies to deal with global radiation may be related to important aspects of species biology and ecology by reflecting, transmitting or absorbing the radiation of varying wavelengths differently. The elytra capacity to manage infrared, visible and ultraviolet radiations (from 185 to 1400 nm) was assessed with a spectrophotometric analysis in five Canthon species of dung beetles; we calculated the reflectance, transmittance and absorbance capacity of the elytra of these species. These species have different ecologies: two species preferentially inhabit forest areas (Canthon angularis and Canthon lividus lividus), two species preferentially inhabit open areas (Canthon chalybaeus and Canthon tetraodon) including agricultural crops, and one species does not present a clear habitat preference and can be found in both habitats (Canthon quinquemaculatus). All the species show a similar pattern in which the light from shorter wavelengths and higher frequencies is almost entirely absorbed by the elytra, while radiation from longer wavelengths and lower frequencies can mostly pass through the elytra. However, C. quinquemaculatus seems to have significantly higher rates of reflectance and transmittance in the visible- and near-infrared spectrum. This different pattern found in C. quinquemaculatus may be associated with its capacity to establish populations both in agricultural and forest areas.

Ivermectin residues disrupt dung beetle diversity, soil properties and ecosystem functioning: An interdisciplinary field study.

Ivermectin is the most common endectocide used to control parasites affecting livestock. Short-term physiological and behavioural effects of ivermectin on dung beetles may have long-term consequences for beetle populations and ecosystem functioning. Long-term effects of the use of ivermectin can be estimated by comparing dung assemblages and ecosystem functions in areas with conventional ivermectin-treated livestock and environmentally similar areas in which livestock are not treated with veterinary medical products (organic farming). In this study, we investigated both short-term and long-term effects of the administration of ivermectin on the characteristics of dung beetle assemblages and the services they provided in a protected area (Doñana National Park, SW Spain). We examined short-term dung colonization, dwelling, relocation, and disaggregation rates and the associations between these processes and the key assemblage parameters of species richness, abundance, biomass and functional diversity. Furthermore, we analysed changes in soil physical-chemical properties and processes. Short-term differences were observed in the total amount of dung relocated by dung beetles at different colonization vs. emigration stages, suggesting that dung beetles in this area were affected by the recent treatments of livestock with ivermectin. Moreover, short-term effects could also be responsible for the significant differences in dung spreading rates between sites. Conventional use of ivermectin disrupted ecosystem functioning by affecting species richness, abundance and biomass. The decrease in diversity parameters was related to a reduction in the functional efficiency, which resulted in the long-term accumulation of dung on the ground and considerable changes in soil functionality.

Exoskeleton may influence the internal body temperatures of Neotropical dung beetles (Col. Scarabaeinae).

The insect exoskeleton is a multifunctional coat with a continuum of mechanical and structural properties constituting the barrier between electromagnetic waves and the internal body parts. This paper examines the ability of beetle exoskeleton to regulate internal body temperature considering its thermal permeability or isolation to simulated solar irradiance and infrared radiation. Seven Neotropical species of dung beetles (Coleoptera, Scarabaeinae) differing in colour, surface sculptures, size, sexual dimorphism, period of activity, guild category and altitudinal distribution were studied. Specimens were repeatedly subjected to heating trials under simulated solar irradiance and infrared radiation using a halogen neodymium bulb light with a balanced daylight spectrum and a ceramic infrared heat emitter. The volume of exoskeleton and its weight per volume unit were significantly more important for the heating rate at the beginning of the heating process than for the asymptotic maximum temperature reached at the end of the trials: larger beetles with relatively thicker exoskeletons heated more slowly. The source of radiation greatly influences the asymptotic temperature reached, but has a negligible effect in determining the rate of heat gain by beetles: they reached higher temperatures under artificial sunlight than under infrared radiation. Interspecific differences were negligible in the heating rate but had a large magnitude effect on the asymptotic temperature, only detectable under simulated sun irradiance. The fact that sun irradiance is differentially absorbed dorsally and transformed into heat among species opens the possibility that differences in dorsal exoskeleton would facilitate the heat gain under restrictive environmental temperatures below the preferred ones. The findings provided by this study support the important role played by the exoskeleton in the heating process of beetles, a cuticle able to act passively in the thermal control of body temperature without implying energetic costs and metabolic changes.

Beetle Exoskeleton May Facilitate Body Heat Acting Differentially across the Electromagnetic Spectrum.

Exoskeletons of beetles and their associated morphological characteristics can serve many different functions, including thermoregulation. We study the thermal role of the exoskeleton in 13 Geotrupidae dung beetle species using heating experiments under controlled conditions. The main purpose was to measure the influence of heating sources (solar radiance vs. infrared), animal position (dorsal exposure vs. ventral exposure), species identity, and phylogenetic relationships on internal asymptotic temperatures and heating rates. The thermal response was significantly influenced by phylogenetic relatedness, although it was not affected by the apterous condition. The asymptotic internal temperature of specimens was not affected by the thoracic volume but was significantly higher under simulated sunlight conditions than under infrared radiation and when exposed dorsally as opposed to ventrally. There was thus a significant interaction between heating source and body position. Heating rate was negatively and significantly influenced by thoracic volume, and, although insignificantly slower under simulated sunlight, it was significantly affected by body position, being faster under dorsal exposure. The results constitute the first evidence supporting the hypothesis that the beetle exoskeleton acts differentially across the electromagnetic spectrum determining internal body temperatures. This interesting finding suggests the existence of a kind of passive physiology imposed by the exoskeleton and body size, where interspecific relationships play a minor role.

Using indigenous knowledge to link hyper-temporal land cover mapping with land use in the Venezuelan Amazon: "The Forest Pulse" / Utilización de conocimiento indígena para relacionar el mapeado hiper-temporal de coberturas de suelo con el uso del territorio en el Amazonas venezolano: "El Pulso del Bosque"

Abstract:Remote sensing and traditional ecological knowledge (TEK) can be combined to advance conservation of remote tropical regions, e.g. Amazonia, where intensive in situ surveys are often not possible. Integrating TEK into monitoring and management of these areas allows for community participation, as well as for offering novel insights into sustainable resource use. In this study, we developed a 250 m resolution land-cover map of the Western Guyana Shield (Venezuela) based on remote sensing, and used TEK to validate its relevance for indigenous livelihoods and land uses. We first employed a hyper-temporal remotely sensed vegetation index to derive a land classification system. During a 1 300 km, eight day fluvial expedition in roadless areas in the Amazonas State (Venezuela), we visited six indigenous communities who provided geo-referenced data on hunting, fishing and farming activities. We overlaid these TEK data onto the land classification map, to link land classes with indigenous use. We characterized land classes using patterns of greenness temporal change and topo-hydrological information, and proposed 12 land-cover types, grouped into five main landscapes: 1) water bodies; 2) open lands/forest edges; 3) evergreen forests; 4) submontane semideciduous forests, and 5) cloud forests. Each land cover class was identified with a pulsating profile describing temporal changes in greenness, hence we labelled our map as "The Forest Pulse". These greenness profiles showed a slightly increasing trend, for the period 2000 to 2009, in the land classes representing grassland and scrubland, and a slightly decreasing trend in the classes representing forests. This finding is consistent with a gain in carbon in grassland as a consequence of climate warming, and also with some loss of vegetation in the forests. Thus, our classification shows potential to assess future effects of climate change on landscape. Several classes were significantly connected with agriculture, fishing, overall hunting, and more specifically the hunting of primates, Mazama americana, Dasyprocta fuliginosa, and Tayassu pecari. Our results showed that TEK-based approaches can serve as a basis for validating the livelihood relevance of landscapes in high-value conservation areas, which can form the basis for furthering the management of natural resources in these regions. Rev. Biol. Trop. 64 (4): 1661-1682. Epub 2016 December 01.

Resumen:La teledetección y el conocimiento ecológico tradicional (CET) se pueden combinar para avanzar en la conservación de regiones tropicales remotas como la Amazonía, donde la toma de datos intensiva in situ a menudo es imposible. Integrar el CET en el seguimiento y el manejo de estas áreas permite la participación de la comunidad, y ofrece nuevos puntos de vista sobre el uso sostenible de los recursos naturales. En este estudio se desarrolla un mapa de cobertura del suelo del Escudo Guayanés (Venezuela), con una resolución espacial de 250 m, basado en datos de teledetección, y se utiliza el CET para validar su relevancia en relación con la subsistencia de los pueblos indígenas y el uso que éstos hacen del territorio. En primer lugar se ha empleado un índice de vegetación basado en teledetección hiper-temporal para realizar una clasificación del territorio. Durante una expedición fluvial de 8 días, a lo largo de 1 300 km por áreas sin carreteras en el Estado Amazonas (Venezuela), se han visitado seis comunidades que han proporcionado datos geo-referenciados sobre sus actividades cinegéticas, pesqueras y agrícolas. Estos datos de CET se han superpuesto al mapa de clasificación, con el fin de relacionar las clases de coberturas con los usos indígenas. Se han caracterizado las clases de cobertura en función de patrones de cambio temporal del verdor y la topo-hidrografía, y se han propuesto 12 tipos de cobertura del suelo, agrupadas en cinco tipos principales de paisaje: 1) masas de agua; 2) campo abierto/ márgenes del bosque; 3) bosques siempre-verdes; 4) bosques semi-caducifolios submontanos; y 5) bosques nublados. Cada clase de cobertura del suelo se ha identificado con un perfil pulsátil que describe cambios temporales en el verdor, de ahí que el mapa haya sido titulado "El Pulso del Bosque". Estos perfiles de verdor han mostrado una tendencia ligeramente ascendente, durante el periodo 2000 a 2009, en las clases que representan pastizales y zonas de matorral, así como una tendencia ligeramente decreciente en las clases que representan bosques. Este hallazgo es compatible con la ganancia de carbono en los pastizales como consecuencia del calentamiento del clima, y también con una cierta pérdida de vegetación en los bosques. De este modo, nuestra clasificación muestra potencial para la evaluación de efectos futuros del cambio climático sobre el paisaje. Algunas clases han resultado estar significativamente relacionadas con la agricultura, la pesca, la caza como práctica general, y más concretamente con la caza de primates, de Mazama Americana, Dasyprocta fuliginosa, y Tayassu pecari. Los resultados demuestran la utilidad de las aproximaciones basadas en CET como base para validar la importancia del paisaje, en áreas con alto valor de conservación, para la supervivencia de las personas, lo que proporciona una base para avanzar en el manejo de los recursos naturales en estas regiones.

The use of occurrence data to predict the effects of climate change on insects.

Experimental information on the roles played by climatic factors in determining the ecology and distribution of insect species is scarce. This has stimulated the increasing use of the climatic characteristics of the localities in which the species are observed to derive predictions under different climatic scenarios (the so called species-distribution models or SDMs). This text reviews the main limitations of these correlative models when they are applied to organisms, such as insects, that are characterized by a high degree of collector bias and incompleteness. It is argued that SDMs must rely solely on presence information, rejecting the use of background or pseudoabsences, and that we are not predicting the future distribution of a species but exploring the future location of the climatic conditions in which a species was observed. The scarcity and bias of the available occurrence information in insects as well as our ignorance about the non-climatic factors delimiting species ranges forces us to be extremely careful. It is therefore desirable to avoid the use of central tendency measures reflecting supposed optimum niche conditions because they are particularly dependent on the quantity and biases of the occurrence information. The use of simple algorithms and procedures aimed at extracting information on environmental limits from the available occurrences would be more convenient in this case.

A protocol for analysing thermal stress in insects using infrared thermography.

The study of insect responses to thermal stress has involved a variety of protocols and methodologies that hamper the ability to compare results between studies. For that reason, the development of a protocol to standardize thermal assays is necessary. In this sense, infrared thermography solves some of the problems allowing us to take continuous temperature measurements without handling the individuals, an important fact in cold-blooded organisms like insects. Here, we present a working protocol based on infrared thermography to estimate both cold and heat thermal stress in insects. We analyse both the change in the body temperature of individuals and their behavioural response. In addition, we used partial least squares regression for the statistical analysis of our data, a technique that solves the problem of having a large number of variables and few individuals, allowing us to work with rare or endemic species. To test our protocol, we chose two species of congeneric, narrowly distributed dung beetles that are endemic to the southeastern part of the Iberian Peninsula. With our protocol we have obtained five variables in the response to cold and twelve in the response to heat. With this methodology we discriminate between the two flightless species of Jekelius through their thermal response. In response to cold, Jekelius hernandezi showed a higher rate of cooling and reached higher temperatures of stupor and haemolymph freezing than Jekelius punctatolineatus. Both species displayed similar thermoregulation ranges before reaching lethal body temperature with heat stress. Overall, we have demonstrated that infrared thermography is a suitable method to assess insect thermal responses with a high degree of sensitivity, allowing for the discrimination between closely related species.

Using indigenous knowledge to link hyper-temporal land cover mapping with land use in the Venezuelan Amazon: "The Forest Pulse".

Remote sensing and traditional ecological knowledge (TEK) can be combined to advance conservation of remote tropical regions, e.g. Amazonia, where intensive in situ surveys are often not possible. Integrating TEK into monitoring and management of these areas allows for community participation, as well as for offering novel insights into sustainable resource use. In this study, we developed a 250 m resolution land-cover map of the Western Guyana Shield (Venezuela) based on remote sensing, and used TEK to validate its relevance for indigenous livelihoods and land uses. We first employed a hyper-temporal remotely sensed vegetation index to derive a land classification system. During a 1 300 km, eight day fluvial expedition in roadless areas in the Amazonas State (Venezuela), we visited six indigenous communities who provided geo-referenced data on hunting, fishing and farming activities. We overlaid these TEK data onto the land classification map, to link land classes with indigenous use. We characterized land classes using patterns of greenness temporal change and topo-hydrological information, and proposed 12 land-cover types, grouped into five main landscapes: 1) water bodies; 2) open lands/forest edges; 3) evergreen forests; 4) submontane semideciduous forests, and 5) cloud forests. Each land cover class was identified with a pulsating profile describing temporal changes in greenness, hence we labelled our map as "The Forest Pulse". These greenness profiles showed a slightly increasing trend, for the period 2000 to 2009, in the land classes representing grassland and scrubland, and a slightly decreasing trend in the classes representing forests. This finding is consistent with a gain in carbon in grassland as a consequence of climate warming, and also with some loss of vegetation in the forests. Thus, our classification shows potential to assess future effects of climate change on landscape. Several classes were significantly connected with agriculture, fishing, overall hunting, and more specifically the hunting of primates, Mazama americana, Dasyprocta fuliginosa, and Tayassu pecari. Our results showed that TEK-based approaches can serve as a basis for validating the livelihood relevance of landscapes in high-value conservation areas, which can form the basis for furthering the management of natural resources in these regions.