Paulina Artacho

Austral University of Chile, Puerto Montt, Region de Los Lagos, Chile

Are you Paulina Artacho?

Claim your profile

Publications (14)25.48 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Studies of the relationship of performance and behavioral traits with environmental factors have tended to neglect interindividual variation even though quantification of this variation is fundamental to understanding how phenotypic traits can evolve. In ectotherms, functional integration of locomotor performance, thermal behavior, and energy metabolism is of special interest because of the potential for coadaptation among these traits. For this reason, we analyzed interindividual variation, covariation, and repeatability of the thermal sensitivity of maximal sprint speed, preferred body temperature, thermal precision, and resting metabolic rate measured in ca. 200 common lizards (Zootoca vivipara) that varied by sex, age, and body size. We found significant interindividual variation in selected body temperatures and in the thermal performance curve of maximal sprint speed for both the intercept (expected trait value at the average temperature) and the slope (measure of thermal sensitivity). Interindividual differences in maximal sprint speed across temperatures, preferred body temperature, and thermal precision were significantly repeatable. A positive relationship existed between preferred body temperature and thermal precision, implying that individuals selecting higher temperatures were more precise. The resting metabolic rate was highly variable but was not related to thermal sensitivity of maximal sprint speed or thermal behavior. Thus, locomotor performance, thermal behavior, and energy metabolism were not directly functionally linked in the common lizard.
    Physiological and Biochemical Zoology 07/2013; 86(4):458-469. · 2.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Aim We provide insights into one of the most widespread biological invasions by reconstructing the molecular phylogeographic history of non-native populations of the land snail Cornu aspersum in austral South America. The goals of this work were: (1) to examine the genetic diversity of native vs. non-native populations of C. aspersum; (2) to analyze the species’ history of dispersal and colonization in austral South America; (3) to compare the biogeographic patterns of native and introduced populations; and (4) to identify signs of population bottlenecks and /or multiple independent introductions that could explain the current genetic diversity. Location North Africa, northwest Europe, North America (California, U.S.), and South America (Chile). Methods Sequence data from mitochondrial Cytochrome b (Cytb) gene was obtained from C. aspersum individuals collected from two localities subject to recent introductions (Californian and Chilean populations in North and South America, respectively) and compared it with previously published data from the species’ native range (northeast and northwest Africa), as well as with data from a previous introduction (northwest Europe). Genetic variation within and among groups was quantified. Genetic structure was inferred by analysis of molecular variance (AMOVA). Phylogenetic and genetic diversity analyses were used to reconstruct phylogeographical patterns. Results Among the 204 sequences from native and non-native populations, we identified 111 haplotypes, from which only three were shared between American and European populations, and no haplotypes were shared between Africa and the introduced populations. The analysis of genetic distances placed European populations between American and African populations. The AMOVAs showed that most of the genetic variance is present within populations rather than among populations or among localities. Haplotype network and phylogenetic analyses consistently demonstrated the existence of two major clades, separating the Tunisian populations and the American populations. Conclusions Genetic diversity and genealogical relationships support the hypothesis of multiple introductions of C. aspersum into austral South America. At least a portion of the current genetic diversity of Chilean populations derives from North American and European (France, Italy and Spain) populations. Keywords: Alien species, biogeography, molluscs, agricultural pests, bottlenecks, multiple introductions.
    Evolutionary ecology research 01/2013; 15. · 0.92 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cyclically parthenogenetic animals such as aphids are able alternating sexual and asexual reproduction during its life cycle, and represent good models for studying short-term evolutionary consequences of sex. In aphids, different morphs, whether sexual or asexual, winged or wingless, are produced in response to specific environmental cues. The production of these morphs could imply a differential energy investment between the two reproductive phases (i.e., sexual and asexual), which can also be interpreted in terms of changes in genetic variation and/or trade-offs between the associated traits. In this study we compared the G-matrices of energy metabolism, life-history traits and morph production in 10 clonal lineages (genotypes) of the pea aphid, Acyrthosiphon pisum, during both sexual and asexual phases. The heritabilities (broad-sense) were significant for almost all traits in both phases; however the only significant genetic correlation we found was a positive correlation between resting metabolic rate and production of winged parthenogenetic females during the asexual phase. These results suggest the pea aphid shows some lineage specialization in terms of energy costs, but a higher specialization in the production of the different morphs (e.g., winged parthenogenetic females). Moreover, the production of winged females during the asexual phase appears to be more costly than wingless females. Finally, the structures of genetic variance-covariance matrices differed between both phases. These differences were mainly due to the correlation between resting metabolic rate and winged parthenogenetic females in the asexual phase. This structural difference would be indicating that energy allocation rules changes between phases, emphasizing the dispersion role of asexual morphs.
    Journal of insect physiology 04/2011; 57(7):986-94. · 2.24 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: The climatic variability hypothesis states that, as the range of climatic fluctuation experienced by terrestrial animals increases with latitude, individuals at higher latitudes should be more plastic than individuals inhabiting lower latitudes. However, it is unclear whether comparatively high flexibility at higher latitudes is due to the direct effect of climatic variability or to other factors associated with latitude. Aim: To investigate the relationship between phenotypic flexibility, geographical latitude, and climatic variability using a dataset where latitude and climatic variability are inversely related. Methods: We assessed the physiological plasticity to cope with thermal change (10C vs. 20C), at the level of metabolic rate and organ dry weight, in three populations of the brown garden snail (Cornu aspersum): Viña del Mar (3320S, 7132W), with high temperature and rainfall variability; Concepción (3647S, 737W), with a narrow range of temperature variability and intermediate rainfall variability; and Valdivia (3938S, 735W), with low temperature and rainfall variability. Results: Standard metabolic rate was higher at 20C than at 10C, but did not differ between populations. Intestine dry weight did not differ among populations but it was higher at 20C than at 10C, particularly for individuals from the Viña del Mar and Conception populations. Hepatopancreas and kidney dry weight differed between populations, which was due to higher values in Viña del Mar at 20C. Conclusions: Flexibility in the weight of the organs analysed changed in a similar fashion to annual temperature variation at each locality, suggesting that, as stated by the climatic variability hypothesis, climatic variability is the main force behind physiological plasticity.
    Evolutionary ecology research 01/2011; 13(1):1-13. · 0.92 Impact Factor
  • Paulina Artacho, Roberto F Nespolo
    [Show abstract] [Hide abstract]
    ABSTRACT: Phenotypic selection is widely recognized as the primary cause of adaptive evolution in natural populations, a fact that has been documented frequently over the last few decades, mainly in morphological and life-history traits. The energetic definition of fitness predicts that natural selection will maximize the residual energy available for growth and reproduction, suggesting that energy metabolism could be a target of selection. To address this problem, we chose the garden snail, Helix aspersa (Cornu aspersum). We performed a seminatural experiment for measuring phenotypic selection on standard metabolic rate (SMR), the minimum cost of maintenance in ectotherm organisms. To discount selection on correlated traits, we included two additional whole-organism performance traits (mean speed and maximum force of dislodgement). We found a combination of linear (negative directional selection, beta=-0.106 +/- 0.06; P= 0.001) and quadratic (stabilizing selection, gamma=-0.012 +/- 0.033; P= 0.061) selection on SMR. Correlational selection was not significant for any possible pair of traits. This suggests that individuals with average-to-reduced SMRs were promoted by selection. To the best of our knowledge, this is the first study showing significant directional selection on the obligatory cost of maintenance in an animal, providing support for the energetic definition of fitness.
    Evolution 03/2009; 63(4):1044-50. · 4.86 Impact Factor
  • Source
    Paulina Artacho, Roberto F Nespolo
    [Show abstract] [Hide abstract]
    ABSTRACT: During the past 2 decades, interest in interindividual variation in performance traits has increased considerably among physiological ecologists. A great deal of this interest has focused on repeatability studies of physiological traits. One of the most important physiological traits in animals is whole-animal metabolism because it reflects several aspects of an organism's energy budget. However, in order to respond to natural selection (ultimately), this variable should be consistent over most of an individual's life history. We studied energy metabolism (CO2 production, (.-)V(CO2)) in two of the southernmost populations of Helix aspersa land snails, a cosmopolitan species that colonized most of the human-inhabited world. Our results show that H. aspersa exhibits a relatively lower than expected (.-)V(CO2) compared with that described in the few other published studies on this species and that there is no significant difference between populations (Valdivia (.-)V(CO2) = 0.21 +/- 0.01 mL CO2 h(-1); Concepción (.-)V(CO2) = 0.20 +/- 0.01 mL CO2 h(-1); mean body mass = 4.2 g). Repeatability of (.-)V(CO2) in land snails was significant and was not statistically different in both populations (Valdivia: tau = 0.42; Concepción: tau = 0.31). These results suggest that energy metabolism is repeatable and can eventually respond to selection in land snails. We argue that land snails are good, though underutilized, models for evolutionary physiology studies.
    Physiological and Biochemical Zoology 02/2009; 82(2):181-9. · 2.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Avian bioenergetic studies suggest that, compared with other vertebrates, birds are efficient thermoregulators. However, most avian physiological studies have been performed in species of small body masses (less than 1 kg). In contrast to what might be anticipated, thermoregulatory abilities of large, flying birds are scarcely studied, especially in temperate zones and aquatic systems. In order to determine short-term metabolic adjustment after thermal challenge, we studied the bioenergetics of a South American anseriform, the black-necked swan (Cygnus melanocoryphus). Our results suggest that this swan species exhibits lower resting metabolic rate compared with other anseriforms, and some hetherothermia. In addition, the black-necked swans in our study changed "wet" thermal conductance at different ambient temperatures. At our working Ta range (5, 10, 15, 20 and 25 degrees C) calculated values were considerably higher than expected (23%, 26%, 39% and 51% higher than expected, respectively). Our results differ considerably from the only two previous reports in swan species, suggesting that C. melanocoryphus, perhaps due to its temperate distribution, is more sensitive to changes in environmental temperature.
    Comparative biochemistry and physiology. Part A, Molecular & integrative physiology 08/2008; 150(3):366-8. · 2.20 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Living organisms are continuously faced with several forms of environmental perturbation, one of the most important being human activity. In this scenario, the role of physiological studies on wildlife has proved to be important given that in vivo physiological variables reflect a great deal how sensitive animals are to acute environmental changes. We studied the haematological parameters in black-necked swans (Cygnus melanocoryphus) at the Ramsar site at the Carlos Anwandter Sanctuary, which were experiencing a drastic population decrease. Through seven months, body mass (body mass corrected by total length) was reduced 30%, which was followed by significant reductions of haemoglobin concentration, haematocrit and red blood cell count. Mean cell volume and mean cell haemoglobin concentration did not change with time, whereas there was a significant increase of the white blood cells and heterophile / lymphocyte ratio. Our results, together with the published evidence, suggests that the proximal factors associated with the mass mortality and emigration of the black - necked swan population at the "Carlos Anwandter Sanctuary" was a drastic nutritional deficiency, and the potentially toxic effects of iron pollution in the waters of the Ramsar site.
    Comparative Biochemistry and Physiology - Part A Molecular & Integrative Physiology 09/2007; 147(4):1060-6. · 2.17 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: One of the most puzzling features of respiration in insects is cyclic gas exchange (CGE, the extreme form of discontinuous gas exchange-cycles, DGC), a periodic respiratory pattern that appeared independently several times in the evolution of arthropods. Although it is a striking feature of insects and some non-insect species, to date there is no clear knowledge of how widespread it is, or its adaptive significance. Here we show for the first time that a cricket (Cratomelus armatus) from the Stenopelmatidae family exhibits CGE. C. armatus shows a conspicuous, convective O-phase, with significantly repeatable ventilatory period and O-phase duration (intraclass correlation coefficients of 0.51 and 0.74, respectively). Also, C. armatus exhibits high variation in the CGE patterns, ranging from continuous to highly periodic records, sometimes including the classic F-phase. No record went to zero and we found significant (inverse) effects of ambient temperature on O-phase duration but not on the ventilatory period. Average VCO2 and O-phase amplitude (i.e. mean VCO2 of the peaks) increased with temperature whereas the amplitude of the interburst did not change significantly with ambient temperature. C. armatus is a species that lives below ground in humid forests, so our results support the chthonic-hygric hypothesis (i.e. facilitation of gas exchange under hypoxic and hypercapnic conditions, minimizing evaporative water loss), although this assertion needs to be confirmed statistically by a strong inference approach.
    Journal of Experimental Biology 03/2007; 210(Pt 4):668-75. · 3.24 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The application of clinical biochemical techniques to determine the products of intermediary metabolism has proved to be a reliable approach for the study of the physiological state of animals in nature. More specifically, the determination of plasma metabolites, such as glucose, total proteins (PRO), albumin (ALB), globulins (GL), urea, uric acid, triglycerides (TG) and beta-hydroxy-butyrate (BHB), and plasma enzymes such as creatine kinase (CK) and aspartate aminotransferase (AST) in wild animals is a valuable possibility for a non-destructive assessment of health in endangered populations. Since August 2004 to January 2005, we conducted a temporal study in a conservation priority site, the "Carlos Anwandter Nature Sanctuary" to determine blood biochemistry of a wild population of black-necked swans (Cygnus melanocoryphus). This population was experiencing a drastic reduction, according to the actual knowledge about yearly fluctuations in numbers and breeding pairs. In six months, we periodically sampled about 12 swans (a total of 122 individuals), which exhibited a reduction near 30% in body mass (body mass corrected by total length). Our results showed reductions in most plasma biochemical parameters (glucose, PRO, ALB, uric acid, TG) and increase in BHB, which taken together indicated signs of chronic malnutrition. Also, the increase in AST and CK that we found, together with additional evidences of sub-lethal hepatic damage (in dead individuals), and iron pollution in aquatic plants and water confirmed that water pollution was the ultimate cause of this population reduction.
    Comparative Biochemistry and Physiology - Part A Molecular & Integrative Physiology 03/2007; 146(2):283-90. · 2.17 Impact Factor
  • Source
    Revista chilena de historia natural 03/2005; 78(1):161-167. · 0.93 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Evolutionary physiology is a new discipline with roots in comparative physiology. One major change in the emergence of this discipline was an explicit new focus on viewing organisms as the evolutionary products of natural selection. The shift in research emphasis from comparative physiology to evolutionary physiology has resulted in physiological traits becoming important elements in broad research programs of evolution and ecology. Evolutionary quantitative genetics is a theory-based biological discipline that has developed the quantitative tools to test explicit evolutionary hypotheses. The role of quantitative genetics has been paramount, in studying the microevolution of morphology, behavior and life history, but not comparative physiology. As a consequence, little basic information is known such as additive genetic variation of physiological traits and the magnitude of genetically based trade-offs (i.e., genetic correlations) with other traits. Here we explore possible causes for such gap, which we believe are related with the inconsistency of what we call physiological traits across taxonomic and organizational divisions, combined with logistical problems of pedigree-based analyses in complex traits.
    Revista Chilena de Historia Natural. 01/2005; 78(1):161-167.
  • Source
    ROBERTO F. NESPOLO, PAULINA ARTACHO
    Revista Chilena De Historia Natural - REV CHIL HIST NAT. 01/2005; 78(2).
  • Source
    ROBERTO F. NESPOLO, PAULINA ARTACHO
    [Show abstract] [Hide abstract]
    ABSTRACT: Comparative animal physiology and related fields (named here “ecological physiology”) are entering a time of synthesis in the form of a quest for large scales patterns. However, these new approaches need to be supplied by great amounts of data, representative of existing animal forms. We tested whether this is the case by performing a quantitative survey in the most important media for ecological physiologists. We found that ecological physiologists have clear biases toward some taxonomic classes, which represent one third of existing animal phyla. Non–taxonomic characterization of animals (endothermy/ectothermy, aquatic/terrestrial), however, produced a more balanced picture. In addition, ecological physiologists appear to be mostly intraspecific biologists since the great majority of studies were performed in one species. Multispecific studies were the minority and comparable to two – species comparative studies. The later are still being published despite to have been strongly criticized in the past. Cross–tabulation analysis yielded results suggesting that natural populations, vertebrates and terrestrial animals are preferred over artificial populations, aquatic animals and invertebrates. Although we recognize the limitations of our survey, it has the value to indicate that historical biases need to be taken in consideration if more global approaches are being undertaking in this discipline.
    Revista chilena de historia natural 12/2004; 78(2):313-321. · 0.93 Impact Factor