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Due to rapid human expansion in the last century, wildlife roadkill is becoming a concerning threat to biodiversity and human safety. The frequency of roadkill events depends on factors related to specific traits of the road—tortuosity or the presence of fences, among others—and the animal ecology—such as activity patterns, reproductive season, or thermoregulation. These, in turn, are related to environmental factors, with seasonal variations. Here, we assessed roadkill mortality of terrestrial vertebrates over the year. To do this, we sampled 10 road sections (of 3 km, by walk) in the south of Spain for a full year, registering the carcasses of run-over vertebrates. Then, we analysed the spatiotemporal patterns of roadkill events for the four vertebrates’ classes and the effects of road traits (presence of fence, tortuosity, distance to water point) and environmental variables (mean temperature and precipitation). Mammals suffered the highest mortality by roadkill (45.72%). The frequency of collisions was independent of tortuosity, presence of fences, and precipitation, while mean temperature significantly increased the probability of collision of mammals, birds, and reptiles. There was a seasonal effect in the number of collisions, which spatial pattern depended on the class of vertebrates. All this leads us to conclude that, to reduce the impact caused by roadkill mortality on wildlife, we need specific measures to be taken timely in each critical place and for each vertebrate group, Funding for open access publishing: Universidad de Granada/ CBUA. Zaida Ortega was funded by a postdoctoral talent-attraction contract from the Junta de Andalucía, co-funded with European Commission funds.

Wild birds are hosts of

This study was partially funded by projects within the National Plan of the Spanish Ministry of Economy and Competition (CGL2014-55969-P and CGL2017-84938-P), the Spanish Ministry of Science and Innovation (PID2020-118205GB-I00) and the Andalusian government (A.RNM.48.UGR20), co-funded with FEDER funds from the European Union. J. L. R.-S. and E. P. were supported by Erasmus+ grants from the European Union. J. G. B. was supported by an FPU predoctoral contract from the Spanish Ministry of Education (FPU18/03034). Funding for open access charge: Universidad de Granada., Wild birds are hosts of Culicoides from as early on as the nesting stage when constrained to their nests. However, the environmental factors which determine the abundance and composition of Culicoides species within each bird nest are still understudied. We sampled Culicoides from Eurasian blue tit (Cyanistes caeruleus) nests found in 2 types of forests located in southern Spain. Firstly, we monitored the abundance of Culicoides species in bird nests from a dry Pyrenean oak deciduous forest and a humid mixed forest comprising Pyrenean and Holm oaks throughout 2 consecutive years. During the 3rd year, we performed a cross-fostering experiment between synchronous nests to differentiate the role of rearing environment conditions from that of the genetically determined or maternally transmitted cues released by nestlings from each forest. We found 147 female Culicoides from 5 different species in the birds’ nests. The abundance of Culicoides was higher in the dry forest than in the humid forest. Culicoides abundance, species richness and prevalence were greater when the nestlings were hatched later in the season. The same pattern was observed in the cross-fostering experiment, but we did not find evidence that nestling’s features determined by the forest of origin had any effect on the Culicoides collected. These results support the notion that habitat type has a strong influence on the Culicoides affecting birds in their nests, while some life history traits of birds, such as the timing of reproduction, also influence Culicoides abundance and species composition., National Plan of the Spanish Ministry of Economy and Competition (CGL2014-55969-P and CGL2017-84938-P), Spanish Ministry of Science and Innovation (PID2020-118205GB-I00), Andalusian government (A.RNM.48.UGR20), FEDER funds from the European Union, Erasmus+ grants from the European Union, FPU predoctoral contract from the Spanish Ministry of Education (FPU18/03034), Universidad de Granada

Body temperature is important in determining individual performance in ectotherms such as lizards. Environmental temperature decreases with increasing altitude, but nevertheless many lizards inhabit high-altitude environments. The ‘thermal melanism hypothesis’ proposes that a dark dorsal coloration enables darker individuals to heat up faster because they absorb more solar radiation and thus being darker may be advantageous in cold habitats. The aim of the present study is to evaluate how heating rate, cooling rate and net heat gain vary with body size and dorsal skin coloration in Sceloporus grammicus lizards along an altitudinal gradient. We measured these traits multiple times in the same individuals with a radiation heat source and spectrophotometry under laboratory conditions. Our results showed that S. grammicus lizards are smaller and darker at high elevations than at low elevations. In addition, the smallest and darkest lizards showed the greatest heating rate and net heat gain. Therefore, in S. grammicus, we suggest that small body size and dark dorsal coloration provide thermoregulatory benefits in high-altitude environments. Hence, this study supports the thermal melanism hypothesis in a lizard species under varied thermal environments.

We report a new analysis of haemosporidian occurrence in 392 Southern Grey Shrike Lanius meridionalis nestlings previously reported in Hernandez et al. (2017. Haemosporidian prevalence in Southern ...

Ecogeographical patterns describe predictable variation in phenotypic traits between ecological communities. For example, high-altitude animals are expected to show elevated hematological values as an adaptation to the lower oxygen pressure. Mountains act like ecological islands and therefore are considered natural laboratories. However, the majority of ecophysiological studies on blood traits lack replication that would allow us to infer if the pattern reported is a local event or whether it is a widespread pattern resulting from larger-scale ecological processes. In lizards, in fact, the increase of hematological values at high altitudes has received mixed support. Here, for the first time, we compare blood traits in lizards along elevational gradients with replication. We tested the repeatability of blood traits in mesquite lizards between different elevations in three different mountains from the Trans-Mexican Volcanic Belt. We measured hematocrit, hemoglobin concentration, mean corpuscular hemoglobin concentration, and erythrocyte size in blood samples of low, medium, and high-elevation lizards. We obtained similar elevational patterns between mountains, but the blood traits differed among mountains. Middle-altitude populations had greater oxygen-carrying capacity than lizards from low and high altitudes. The differences found between mountain systems could be the result of phenotypic plasticity or genetic differentiation as a consequence of abiotic factors not considered.

We thank the personnel from the Espacio Natural de Sierra Nevada for their constant support. We are also grateful to Concepción Herna´ndez, from the Centre of Scientific Instrumentation at the University of Granada, for her help with the freezing microtome. We are also in debt to Humbert Salvadó (University of Barcelona) for allowing us to use the microscope. Comments from 3 anonymous referees greatly improved the manuscript., Lifespan is one of the main components of life history. Shorter lifespans can be expected in marginal habitats. However, in the case of ectotherms, lifespan typically increases with altitude, even though temperature—one of the main factors to determine ectotherms’ life history—declines with elevation. This pattern can be explained by the fact that a shorter activity time favors survival. In this study, we analyzed how lifespan and other life-history traits of the lizard Psammodromus algirus vary along a 2,200m elevational gradient in Sierra Nevada (SE Spain). Populations at intermediate altitudes (1,200–1,700 m), corresponding to the optimal habitat for this species, had the shortest lifespans, whereas populations inhabiting marginal habitats (at both low and at high altitudes) lived longest. Therefore, this lizard did not follow the typical pattern of ectotherms, as it also lived longer at the lower limit of its distribution, nor did it show a longer lifespan in areas with optimal habitats. These results might be explained by a complex combination of different gradients along the mountain, namely that activity time decreases with altitude whereas food availability increases. This could explain why lifespan was maximum at both high (limited activity time) and low (limited food availability) altitudes, resulting in similar lifespans in areas with contrasting environmental conditions. Our findings also indicated that reproductive investment and body condition increase with elevation, suggesting that alpine populations are locally adapted., Junta de Andalucía, Parque Nacional de Sierra Nevada (referencias GMN / GyB / JMIF y ENSN / JSG / JEGT / MCF)

Current climate warming has already contributed to local extinctions. Amphibians are one of the most sensitive animal groups to climate change, currently undergoing a global decline. Predictive models for Europe and Iberian Peninsula forecast that the future impact of climate change on amphibians will depend on their capacity to alter their distributions by tracking climate warming. In the present study, we explore the responses of Iberian amphibian species to recent climate change, by comparing amphibian distributions between two time periods (1901–1990 vs. 2000–2015). Our findings suggest that, although climatic conditions have changed between the two periods, Iberian amphibians have barely shifted their distribution ranges northwards, with the exception of the southernmost species (Alytes dickhilleni). However, most Iberian amphibians appear to have moved their elevational limits upwards in mountains. Approximately half of the species showed different occupied niches between the two time periods, suggesting that many Iberian amphibians have not been able to reach all the new location with optimal climatic conditions for them. Furthermore, disappearing cold climatic conditions (e.g. those found at mountain tops) limit the potential distribution of cold-adapted species, including European widespread species with their southern margin in the Iberian Peninsula, and endemic species. The combination of a limited ability to shift their ranges and profound climatic changes could pose a challenge to the long-term persistence of Iberian amphibian populations.

The timing of organisms' senescence is developmentally programmed but also shaped by the interaction between environmental inputs and life-history traits. In ectotherms, ageing dynamics are still poorly understood even though their body temperature, metabolism, or growth trajectory are very sensitive to environmental changes. Here, we investigated the role of life-history traits such as age, sex, body size, body condition, and tail autotomy (i.e self-amputation) in shaping telomere length in six populations of the Algerian sand lizard (Psammodromus algirus) distributed along an elevational gradient from 300 to 2500 m above the sea level. Additionally, we compiled the available information on reptiles' telomere length in a review table. Our cross-sectional study shows that older lizards have longer telomeres, which might be mostly linked to the selective disappearance of individuals with shorter telomeres or, alternatively, mediated by a higher expression of telomerase across their life. In fact, variation in telomere length across elevation was explained by age structure of lizards; thus, in contrast to our predictions, altitude had no effect on telomere length in this study system. Telomere length was unaffected by tail regeneration and was sex-independent, but positively correlated with body condition, which might be linked to high somatic investment. Hence, our results suggest that life-history traits such as age or body condition can be major drivers of telomere dynamics for this species, whereas environmental conditions apparently had scarce or no effects on lizard telomeres. Our findings emphasize the relevance of understanding species' life histories for fully disentangling the causes and consequences of differences in ageing in ectotherms.

Animals may face trade-offs when several simultaneous functions or processes compete for limiting resources. In that context, allocation of resources to the most fitness-enhancing competing function can be prioritized. Immune response and locomotor performance are relevant fitness components, mainly due to their important roles as defence against pathogens and predators, respectively. However, both promote oxidative stress and consume energy and metabolites. Consistently, trade-offs between immune response and locomotion have been reported in some taxa. In this work, we examine whether an immune challenge hinders short-distance swimming speed of adult Iberian ribbed newts, Pleurodeles waltl. To that end, we inoculated Escherichia coli cell wall lipopolysaccharide (LPS), an innocuous antigen that triggers an immune response, in the sole pads of experimental newts, and phosphate buffer saline, with no physiological effect, in those of control newts. We estimated immune response as sole pad swelling and calculated swimming speed from videos of newts swimming towards a refuge nearby, 24 h and 7 days after inoculation. Sole pad swelling was greater in LPS-inoculated newts, but short-distance swimming speed was not affected by the immune challenge. These results could indicate priority allocation of resources to locomotion, which might be a consequence of compensatory mechanisms capable of avoiding locomotion impairment due to immune challenge. In any case, these findings could highlight the importance of short-distance escape as an antipredator strategy.

Comments from Mar Comas, the Associate Editor, two anonymous referees and Sami Merilaita have helped to greatly improve the manuscript., The evolution of crypsis when pigmentation is physiologically costly. Predation is one of the main selective forces in nature, frequently selecting for crypsis in prey. Visual crypsis usually implies the deposition of pigments in the integument. However, acquisition, synthesis, mobilisation and maintenance of pigments may be physiologically costly. Here, I develop an optimisation model to analyse how pigmentation costs may affect the evolution of crypsis. The model provides a number of predictions that are easy to test empirically. It predicts that imperfect crypsis should be common in the wild, but in such a way that pigmentation is less than what is required to maximise crypsis. Moreover, optimal crypsis should be closer to “maximal” crypsis as predation risk increases and/or pigmentation costs decrease. The model predicts for intraspecific variation in optimal crypsis, depending on the difference in the predation risk or the costs of pigmentation experienced by different individuals., La evolución de la cripsis cuando la pigmentación es fisiológicamente costosa. La depredación es una de las principales fuerzas de selección de la naturaleza y a menudo favorece la cripsis en las presas. Por lo general, la cripsis visual implica el depósito de pigmentos en el tegumento. Sin embargo, adquirir, sintetizar, movilizar y mantener los pigmentos puede ser fisiológicamente costoso. En este estudio he elaborado un modelo de optimización para analizar cómo pueden afectar los costes de la pigmentación a la evolución de la cripsis. El modelo proporciona una serie de predicciones que son fáciles de probar empíricamente. Predice que la cripsis imperfecta debería ser común en la naturaleza, pero de manera que la pigmentación fuera inferior a la necesaria para que la cripsis sea máxima. Además, la cripsis óptima debería estar más cerca de la cripsis “máxima” a medida que aumenta el riesgo de depredación o disminuye el coste de la pigmentación. El modelo también predice la existencia de variación intraespecífica en la cripsis óptima, que depende de la diferencia en el riesgo de depredación o de los costes de la pigmentación que soportan los diferentes individuos.

Sprint speed is a major performance trait in animal fitness involved in escaping from predators, obtaining food, and defending territory. Biotic and abiotic factors may influence sprint speed in lizards. Temperature decreases at higher altitude. Therefore, lizards at high elevations may require longer basking times to reach optimal body temperatures, increasing their vulnerability to predation and decreasing their time for other activities such as foraging or reproduction. Here, we tested whether the maximum sprint speed of a lizard that shows conservative thermal ecology varied along an altitudinal gradient comprising low (2500 m), middle (3400 m) and high-altitude (4300 m) populations. We also tested whether sprint speed was related to dorsal reflectance at different ecologically relevant temperatures. Given that the lizard Sceloporus grammicus shows conservative thermal ecology with altitude, we expected that overall average sprint speed would not vary with altitude. However, given that darker lizards heat up quicker, we expected that darker lizards would be faster than lighter lizards. Our results suggest that S. grammicus at high altitude are faster and darker at 30 °C, while lizards from low and middle altitude are faster and lighter in color at 20 °C than high altitude lizards. Also, our results suggest a positive relationship between sprint speed and dorsal skin reflectance at 10 and 20 °C. Sprint speed was also affected by snout-vent length, leg length, and leg thickness at 10 °C. These results suggest that, even though predation pressure is lower at extreme altitudes, other factors such as vegetation cover or foraging mode have influenced sprint speed.

Oxidative status has been proposed as an important ecological and evolutionary force given that pro-oxidant metabolites damage molecules, cells and tissues, with fitness consequences for organisms. Consequently, organisms usually face a trade-off between regulating their oxidative status and other physiological traits. However, environmental stressors and the availability of dietary-derived antioxidants vary according to local conditions and, thus, organisms inhabiting different habitats face different oxidative pressures. Still, there is little information on how different environmental conditions influence the oxidative status of animals inhabiting terrestrial environments. In this work, we examined the variation in oxidative status in the blue tit (Cyanistes caeruleus), a bird species with hatching asynchrony. Specifically, we examined the oxidative status of the largest and the smallest nestlings in the brood, inhabiting four forests differing in food availability and ectoparasite prevalence. We measured lipid peroxidation (malondialdehyde; MDA) as a marker of oxidative damage, total antioxidant capacity (Trolox-equivalent antioxidant capacity; TEAC) and antioxidant enzymatic activity (catalase, glutathione S-transferase, glutathione peroxidase) in blood samples. The glutathione peroxidase (GPX) activity differed among the forests, being the highest in the pine forest and the lowest in a mixed oak (Quercus) forest in the most humid area. Lipid peroxidation was higher in larger nestlings, suggesting higher oxidative damage with an increasing growth rate. Neither brood size, laying date, nor ectoparasites were related to the oxidative status of nestlings. These results suggest that nest rearing conditions might shape the oxidative status of birds, having consequences for habitat-dependent variation in regulation of oxidative status.

Capsule: Nestling Southern Grey Shrikes Lanius meridionalis show a high prevalence of haemosporidian parasites including five lineages described here for the first time.Aims: To examine the prevalence of various haemosporidian lineages in nestlings of three separated Iberian populations of the Southern Grey Shrike.Methods: Blood samples were taken from nestling Southern Grey Shrikes from three agroecosystem areas in the Iberian Peninsula. Parasites were detected from blood samples using polymerase chain reaction screening.Resusts: Nestlings were parasitized by 11 different lineages belonging to the genera Haemoproteus (3.8%), Plasmodium (0.5%) and Leucocytozoon (1.8%), including five new undescribed lineages. These are among the highest prevalence levels of haemosporidians parasites (7.4%) for nestlings of passerine birds.Conclusion: Our findings suggest that the distribution of avian haemosporidians is determined by complex effects including climate and biogeography. Most parasite lineages were n...

The uropygial gland is a holocrine complex exclusive to birds that produces an oleaginous secretion (preen oil) whose function is still debated. Herein, I examine critically the evidence for the many hypotheses of potential functions of this gland. The main conclusion is that our understanding of this gland is still in its infancy. Even for functions that are considered valid by most researchers, real evidence is scarce. Although it seems clear that preen oil contributes to plumage maintenance, we do not know whether this is due to a role in reducing mechanical abrasion or in reducing feather degradation by keratinophilic organisms. Evidence for a function against pathogenic bacteria is mixed, as preen oil has been demonstrated to act against bacteria in vitro, but not in vivo. Nor is it clear whether preen oil can combat pathogenic bacteria on eggshells to improve hatching success. Studies on the effect of preen oil against dermatophytes are very scarce and there is no evidence of a function against chewing lice. It seems clear, however, that preen oil improves waterproofing, but it is unclear whether this acts by creating a hydrophobic layer or simply by improving plumage structure. Several hypotheses proposed for the function of preen oil have been poorly studied, such as reduction of drag in flight. Similarly, we do not know whether preen oil functions as repellent against predators or parasites, makes birds unpalatable, or functions to camouflage birds with ambient odours. On the other hand, a growing body of work shows the important implications of volatiles in preen oil with regard to social communication in birds. Moreover, preen oil clearly alters plumage colouration. Finally, studies examining the impact of preen oil on fitness are lacking, and the costs or limitations of preen-oil production also remain poorly known. The uropygial gland appears to have several non-mutually exclusive functions in birds, and thus is likely to be subject to several selective pressures. Therefore, future studies should consider how the inevitable trade-offs among different functions drive the evolution of uropygial gland secretions.

The timing of organisms’ senescence is developmentally programmed but also shaped by the interaction between environmental inputs and life-history traits. In ectotherms, ageing dynamics are still poorly understood despite their particularities concerning thermoregulation, regeneration capacity, or growth trajectory. Here, we investigate the role of life-history traits such as age, sex, body size, body condition, and tail autotomy (i.e self-amputation) in shaping telomere length of six populations of the Algerian sand lizard (Psammodromus algirus) distributed across an elevational gradient from 300 to 2500 meters above the sea level. Additionally, we show in a review table the available information on reptiles’ telomere length. We found that telomeres elongated with lizards’ age. We also observed that body size and age class showed a positive relationship, suggesting that cell replication did not shorten lizards’ telomeres by itself. Elevation affected telomere length in a non-linear way, a pattern that mirrored the variation in age structure across elevation. Telomere length was unaffected by tail autotomy, and was sex-independent, but positively correlated with body condition. Our results show that telomeres elongate throughout the first four years of lizards’ lifetime, a process that stress the role of telomerase in maintaining ectothermic telomeres, and, likely, in extending lifespan in organisms with indeterminate growth. Regarding the non-linear impact that elevation had on telomere length of lizards, our results suggest that habitat (mainly temperature) and organisms’ condition might play a key role in regulation ageing rate. Our findings emphasize the relevance of understanding species’ life histories (e.g. age and body condition) and habitat characteristics for fully disentangling the causes and consequences of lifespan trajectory.

Parasitoid wasps may act as hyperparasites and sometimes regulate the populations of their hosts by a top-down dynamic. Nasonia vitripennis (Walker, 1836) is a generalist gregarious parasitoid that parasitizes several host flies, including the blowfly Protocalliphora Hough, 1899 (Diptera, Calliphoridae), which in turn parasitizes bird nestlings. Nonetheless, the ecological factors underlying N. vitripennis prevalence and parasitoidism intensity on its hosts in natural populations are poorly understood. We have studied the prevalence of N. vitripennis in Protocalliphora azurea (Fallén, 1817) puparia parasitizing wild populations of pied flycatcher (Ficedula hypoleuca) and blue tit (Cyanistes caeruleus) birds in two Mediterranean areas in central and southern Spain. We found some evidence that the prevalence of N. vitripennis was higher in moist habitats in southern Spain. A host-dependent effect was found, since the greater the number of P. azurea puparia, the greater the probability and rate of parasitoidism by the wasp. Our results also suggest that N. vitripennis parasitizes more P. azurea puparia in blue tit nests than in pied flycatcher nests as a consequence of a higher load of these flies in the former. Based on the high prevalence of N. vitripennis in P. azurea puparia in nature, we propose that this wasp may regulate blowfly populations, with possible positive effects on the reproduction of both bird species

Hematological profiles are routinely used to assess the health status of animals. Several methods have been developed for blood cell counting, but they are typically expensive and/or time-consuming. Here, we present a free image-processing software, Mizutama, developed for counting cells in photographs of blood smears. Mizutama uses the thresholding method to transform original photographs into grayscale trinary images. Following a number of parameters, Mizutama searches in the image for cells of a given size, with a nucleus size relative to cytoplasm surface area. The software is not only easy, versatile, and intuitive to handle but also fast when counting cells in photographs. Moreover, we show that it is highly accurate, failing to detect only ca. 1.4% of avian red cells in ordinary microscopic photographs. The Mizutama application may greatly facilitate the counting of erythrocytes and other blood cells in physiological studies, saving time and money.

Predation usually selects for visual crypsis, the colour matching between an animal and its background. Geographic co-variation between animal and background colourations is well known, but how crypsis varies along elevational gradients remains unknown. We predict that dorsal colouration in the lizard Psammodromus algirus should covary with the colour of bare soil—where this lizard is mainly found—along a 2200 m elevational gradient in Sierra Nevada (SE Spain). Moreover, we predict that crypsis should decrease with elevation for two reasons: (1) Predation pressure typically decreases with elevation, and (2) at high elevation, dorsal colouration is under conflicting selection for both crypsis and thermoregulation. By means of standardised photographies of the substratum and colourimetric measurements of lizard dorsal skin, we tested the colour matching between lizard dorsum and background. We found that, along the gradient, lizard dorsal colouration covaried with the colouration of bare soil, but not with other background elements where the lizard is rarely detected. Moreover, supporting our prediction, the degree of crypsis against bare soil decreased with elevation. Hence, our findings suggest local adaptation for crypsis in this lizard along an elevational gradient, but this local adaptation would be hindered at high elevations., This study has been economically supported by the Ministerio de Ciencia e Innovación (project CGL2009-13185).

This study was possible thanks to the collaboration of the Ajuntament de Barcelona, the staff of Mosse`n Cinto Verdaguer gardens, and the Association Galanthus, particularly Sergi Garcia. Comments by one anonymous reviewer improved the manuscript, Predation is one of the main selective forces in nature, frequently selecting potential prey for developing escape strategies. Escape ability is typically influenced by several morphological parameters, such as morphology of the locomotor appendices, muscular capacity, body mass, or fluctuating asymmetry, and may differ between sexes and age classes. In this study, we tested the relationship among these variables and jumping performance in 712 Iberian green frogs Pelophylax perezi from an urban population. The results suggest that the main determinant of jumping capacity was body size (explaining 48% of variance). Larger frogs jumped farther, but jumping performance reached an asymptote for the largest frogs. Once controlled by structural body size, the heaviest frogs jumped shorter distances, suggesting a trade-off between fat storage and jumping performance. Relative hind limb length also determined a small but significant percentage of variance (2.4%) in jumping performance—that is, the longer the hind limbs, the greater the jumping capacity. Juveniles had relatively shorter and less muscular hind limbs than adults (for a given body size), and their jumping performance was poorer. In our study population, the hind limbs of the frogs were very symmetrical, and we found no effect of fluctuating asymmetry on jumping performance. Therefore, our study provides evidence that jumping performance in frogs is not only affected by body size, but also by body mass and hind limb length, and differ between age classes.

Studying the causes of parasite geographic distribution is relevant to understand ecological and evolutionary processes that affect host populations as well as for species conservation. Temperature is one of the most important environmental variables affecting parasite distribution, as raising temperatures positively affect development, reproduction, and rate of transmission of both endo- and ectoparasites. In this context, it is generally accepted that, in mountains, parasite abundance decreases with elevation. However, empirical evidence on this topic is limited. In the present study, we analyzed the elevational variation of hemoparasites and ectoparasites of a lizard, Psammodromus algirus, along a 2,200-m elevational gradient in Sierra Nevada (SE Spain). As predicted, ectoparasite (mites, ticks, mosquitoes, and sandflies) abundance decreased with elevation. However, hemoparasite prevalence and intensity in the lizard augmented with altitude, showing a pattern contrary to their vectors (mites). We suggest that tolerance to hemoparasites may increase with elevation as a consequence of lizards at high altitudes taking advantage of increased body condition and food availability, and reduced oxidative stress. Moreover, lizards could have been selected for higher resistance against hemoparasites at lowlands (where higher rates of replication are expected), thus reducing hemoparasite prevalence and load. Our findings imply that, in a scenario of climate warming, populations of lizards at high elevation may face increased abundance of ectoparasites, accompanied with strong negative effects., This work was funded by the European Union the Spanish government (Ministerio de Ciencia e Innovación and Ministerio de Economía y Ciencia (FEDER-MINECO), projects CGL2009-13185, CGL2014-55969-P, CGL2015-65055-P, and CGL2015-67789. F.J.Z.-C (AP2009-3505) and S.R. (AP2009-1325) were supported by two predoctoral grants from the Ministerio de Ciencia e Innovación (FPU program). F.J.Z.-C was partially supported by a Ramón Areces Foundation postdoctoral fellowship and by a Juan de la Cierva contract.

Achieving optimal body temperature maximizes animal fitness. Since ambient temperature may limit ectotherm thermal performance, it can be constrained in too cold or hot environments. In this sense, elevational gradients encompass contrasting thermal environments. In thermally pauperized elevations, ectotherms may either show adaptations or suboptimal body temperatures. Also, reproductive condition may affect thermal needs. Herein, we examined different thermal ecology and physiology capabilities of the lizard Psammodromus algirus along a 2200-m elevational gradient. We measured field (T(b)) and laboratory-preferred (T(pref)) body temperatures of lizards with different reproductive conditions, as well as ambient (T(a)) and copper-model operative temperature (T(e)), which we used to determine thermal quality of the habitat (d(e)), accuracy (d(b)), and effectiveness of thermoregulation (de-db) indexes. We detected no Tb trend in elevation, while T(a) constrained T(b) only at high elevations. Moreover, while Ta decreased more than 7 °C with elevation, T(pref) dropped only 0.6 °C, although significantly. Notably, low-elevation lizards faced excess temperature (T(e) T(pref)). Notably, de was best at middle elevations, followed by high elevations, and poorest at low elevations. Nonetheless, regarding microhabitat, high-elevation de was more suitable in sun-exposed microhabitats, which may increase exposition to predators, and at midday, which may limit daily activity. As for gender, d(b) and d(e)-d(b) were better in females than in males. In conclusion, P. algirus seems capable to face a wide thermal range, which probably contributes to its extensive corology and makes it adaptable to climate changes.

Tail autotomy is an antipredatory defense that allows lizards to escape predator attacks by shedding their tails. While the benefits of preserving life are indisputable, tail loss implies a number of physiological, social, reproductive and even metabolic costs derived from tail regeneration and reduced motility. In addition, predation risk is increased in lizards with autotomized tails. Metabolic rates increase with body temperature, which in ectotherms depends on external heat sources. Ectotherm thermoregulation is costly in terms of time consumption and exposure to predators, this cost depending on habitat thermal quality. In this work, we seek to disentangle the effects of tail autotomy on field and selected body temperature of an accurately thermoregulating lizard Psammodromus algirus in different thermal environments along a 2200-m elevational gradient. We test two non-mutually exclusive hypotheses. According to a physiological hypothesis, we expect lizards with autotomized tails to show higher body temperatures that allow them to regenerate lost tissues faster, at least when the thermal environment is not limiting (at mid and low elevations). By contrast, according to an ethological hypothesis, we expect lizards with autotomized tails to avoid exposure to predators by reducing thermoregulation time, thus showing lower temperatures than lizards with non-autotomized tails. However, we found that the tail state did not significantly affect lizard field or selected body temperatures. On the one hand, a warmer thermal optimum could imply greater exposure to predators during basking, making motility-impaired lizards with autotomized tails more vulnerable, which could explain why the physiological hypothesis of autotomy thermal effect does not apply. On the other hand, lower body temperatures could be physiologically costly for lizards, which, together with the other costs resulting from tail autotomy, could jeopardize lizard fitness. Therefore, both hypotheses were not supported.

Mountains imply enormous environmental variation, with alpine habitats entailing harsh environments, especially for ectotherms such as lizards. This environmental variability also may imply variation in prey availability. However, little is known about how lizard trophic ecology varies with elevation. In this study, we analyze diet, prey availability, prey selection, and trophic niche width in the lacertid lizard Psammodromus algirus along a 2,200-m elevational gradient in the Sierra Nevada (SE Spain). The analysis of fecal samples has shown that Orthoptera, Formicidae, Hemiptera, Coleoptera, and Araneae are the main prey, although, according to their abundance in pitfall traps, Formicidae and Coleoptera are rejected by the lizard whereas Orthoptera, Hemiptera, and Araneae are preferred. Prey abundance and diversity increase with elevation and diet subtly varies along with the elevational gradient. The consumption of Coleoptera increases with elevation probably as a consequence of the lizard foraging more in open areas while basking. The electivity for Araneae increases with elevation. Araneae are rejected in the lowlands—where they are relatively abundant—whereas, at high elevation, this lizard positively selects them, despite they being less abundant. The lizard trophic niche width expands with elevation due to concomitant greater prey diversity and hence this lizard feeds on more prey types in highlands. Although no sex difference in diet has been found, the trophic niche is broader in females than males. As a whole, alpine lizards show a trophic niche similar to that found at lower elevations, suggesting that P. algirus is well adapted to the harsh environment found in alpine areas., This study was economically supported by the Ministerio de Ciencia e Innovación (project CGL2009-13185). Two predoctoral grants (FPU program) from the Ministerio de Educación (Ministry of Education) supported FJZC (ref: AP2009-3505) and SR (ref: AP2009-1325). IAB received a grant for initiation to the research by the University of Granada.

Predators and pathogens can diminish organisms’ fitness, and consequently natural selection favors antipredatory and antiparasitic strategies. Nevertheless, as both kinds of strategies consume resources, animals cannot maximize investment in both strategies simultaneously, which should lead to trade-offs between the two. Accordingly, we hypothesize that there is a trade-off between sprint capacity and immune response, which are among the most important antipredatory and antiparasitic strategies, respectively, of many animals. Consequently, we predict that animals eliciting an immune response should reduce their sprint capacity. We experimentally tested this prediction in the lizard Psammodromus algirus. A group of lizards was inoculated with the antigen LPS (lipopolysaccharide of the cell wall of Escherichia coli), which activates the immune system, whereas the other group (control) was inoculated with phosphate buffer, which has no physiological effect. Before and after the inoculations, we filmed sprint capacity of lizards, estimating the maximal sprint speed. Males were faster than females before the activation of their immune system. Nonetheless, males’ sprint speed diminished after the inoculation of LPS, whereas females’ did not. Therefore, our results support the hypothesis of a trade-off between sprint speed and immune response in males. Consequently, male lizards combating a pathogen may suffer either higher risk of predation, or reduced fitness if they avoid this risk by spending more time in shelter.