Effects of energy and thermoregulation time on physiological state and sexual signal in a lizard

Abstract

Theory of sexual selection states that males often develop showy signals, which reduce their survival but increase their reproductive success. During mate choice, these conspicuous signals can be honest indicators of individual quality conveying information about the signaler's physiological state. Sexually selected signals are influenced by many environmental factors; however, whether signals and physiological state are affected together is rarely studied. The ultraviolet-blue throat color of male Lacerta viridis is an intra- and intersexually selected signal connected to blood parasite infection and influenced by environmental factors. The aim of this study was to experimentally investigate how ecologically relevant environmental factors affect color signal intensity and key physiological traits parallel. During the mating season, we exposed 40 adult male lizards infected with blood parasites to food and basking time treatments in a full factorial design. We measured color, amount of reactive oxygen metabolites (ROMs), hematocrit, immunocompetence, and blood parasite intensity before and after treatments. High basking time resulted in elevated immunocompetence coupled with increased ROMs. The high food treatment increased nuptial color brightness, but also increased ROMs and decreased immunocompetence. In summary, our study provides experimental evidence about environmentally induced parallel changes in an honest sexual signal and several quality-indicator physiological traits. We showed that available energy and time for high metabolism have independent and sometimes opposite effects on individual state.

Relationship between oxidative stress and sexual coloration of lizards depends on thermal habitat

“…Oxidative status was characterized by the concentration of oxidative metabolites (ROM) in the blood plasma, measured with Diacron d-ROMs Test (Diacron Labs s.r.l., Grosseto, Italy). The tests were conducted following the protocol detailed in Mészáros et al (2017).…”

Sexual selection in a tropical toad: Do female toads choose brighter males in a species with rapid colour change?

“…Bright, colourful signals allow animals to discriminate between individuals and can influence behavioural decisions and social interactions. Such signals may convey meaningful information about an individual's quality (Doucet & Montgomerie, 2003; Sheldon et al., 2003; Zhao et al., 2018), physiological state (Mészáros et al., 2017; York et al., 2016), reproductive state (Galván et al., 2016; Kodric‐Brown, 1998), social status (Gerald, 2001; Martín et al., 2007) or other information. Conspicuous visual signals arise from both natural and sexual selection pressures and serve diverse functions across taxa (Andersson, 1994; Bradbury & Vehrencamp, 2011).…”

Linking behavioral thermoregulation, boldness, and individual state in male Carpetan rock lizards

“…Ecology of thermoregulation is well studied in reptiles (see Bajer, Molnár, Török, & Herczeg, 2012; Bauwens, Hertz, & Castilla, 1996; Berkel & Clusella‐Trullas, 2018; Herczeg et al., 2004, 2006, 2008; Mészáros, Herczeg, Bajer, Török, & Molnár, 2018; Rusch & Angilletta, 2016), especially in small‐ to medium‐sized heliothermic lizards, whose body temperature is maintained by behavioral (timing of activity, microhabitat use, adopted posture) rather than by physiological adjustments (Angilletta, Cooper, et al, 2002; Bauwens et al., 1996; Huey & Slatkin, 1976; Van Damme & Bauwens, 1991). Differences in individual thermal preferences seem to play a key role for behavioral consistency in reptiles (Goulet, Thompson, Michelangeli, et al, 2017; Mell et al., 2016; Stapley, 2006; Waters, Bowers, & Burghardt, 2017).…”