title: The role of metabolism in understanding the altitudinal segregation pattern of two potentially interacting lizards.
abstract: Sympatric species from the same ecological guild, that exhibit partial altitudinal segregation, can potentially interact in areas of syntopic occurrence. Besides general species' ecology, physiology can provide important answers about species interactions reflected in altitudinal patterns. Lizards Podarcis muralis and Iberolacerta horvathi exhibit partial altitudinal segregation, while they strongly resemble in overall morphology and ecology (diet, daily and seasonal activity pattern), but show certain degree of physiological dissimilarity. They have similar mean preferred body temperatures and patterns of seasonal and daily variations but differ in the magnitude of seasonal variation. Since an ectotherm metabolism is highly dependent on body temperature, thermoregulation is expected to directly affect their metabolism. We compared metabolic rates of adult males from an area of sympatry, measured under two temperature regimes (20°C and 28°C). Both species increased metabolic rates with temperature in a similar pattern. We also compared electron transport activity from tail tissues which provide values of species' potential metabolic activity (enzymatic capacity). Species clearly differed in potential metabolic activity; I. horvathi attained higher values than P. muralis. No difference was detected in how species exploited this potential (calculated from the ratio of electron transport activity and metabolic rates). However, we observed higher potential metabolic activity I. horvathi which together with the ability to thermoregulate more precisely could represent a higher competitive advantage over P. muralis in thermally more restrictive environments such as higher altitudes. Understanding of metabolism seems to provide valuable information for understanding recent distributional patterns as well as species interactions.
authors.affiliation: CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, No 7, Vairão, 4485-661 Vila do Conde, Portugal; Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, SI-1000 Ljubljana, Slovenia. Electronic address: anamarija.zagar@gmail.com.
authors.forename: Anamarija
authors.initials: A
authors.lastname: Žagar
authors.affiliation: National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia. Electronic address: tatjana.simcic@nib.si.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Simčič
authors.affiliation: CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, No 7, Vairão, 4485-661 Vila do Conde, Portugal. Electronic address: carretero@cibio.up.pt.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Carretero
authors.affiliation: National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia. Electronic address: al.vrezec@nib.si.
authors.forename: Al
authors.initials: A
authors.lastname: Vrezec
mesh_terms: D000531:Altitude; D000818:Animals; D001481:Basal Metabolism / Q000502:physiology; D004579:Electron Transport; D008116:Lizards / Q000378:metabolism*; D008297:Male; D017524:Slovenia; D013045:Species Specificity; D061350:Sympatry; D013696:Temperature; D013997:Time Factors
keywords: Electron transport system activity; Iberolacerta; Interaction; Metabolic rate; Podarcis; Reptiles