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UV-deprived coloration reduces success in mate acquisition in male sand lizards (Lacerta agilis).

Olsson M, Andersson S, Wapstra E - PLoS ONE (2011)

Bottom Line: The role of UV in communication has, however, never been examined.Here we show that when measured immediately after spring skin shedding, there is also signaling in the UV.These results suggest that at least two colour traits in sand lizards, badge area and UV, contribute to rival deterrence and/or female choice on UV characters, which elevates success in mate acquisition in UV intact male sand lizards.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Sydney, Sydney, Australia. mats.olsson@sydney.edu.au

ABSTRACT

Background: Recent work on animal signals has revealed a wide occurrence of UV signals in tetrapods, in particular birds, but also in lizards (and perhaps other Squamate reptiles). Our previous work on the Swedish sand lizard (Lacerta agilis) has verified, both in correlative selection analyses in the wild and with laboratory and field experiments, the importance of the green 'badge' on the body sides of adult males for securing mating opportunities, probably mostly through deterring rival males rather than attracting females. The role of UV in communication has, however, never been examined.

Methodology/principal findings: Here we show that when measured immediately after spring skin shedding, there is also signaling in the UV. By UV-depriving the signal (reflectance) with sun block chemicals fixated with permeable, harmless spray dressing, we show that males in the control group (spray dressing only) had significantly higher success in mate acquisition than UV-deprived males.

Conclusions/significance: These results suggest that at least two colour traits in sand lizards, badge area and UV, contribute to rival deterrence and/or female choice on UV characters, which elevates success in mate acquisition in UV intact male sand lizards.

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Related in: MedlinePlus

Mating success in male sand lizards depending on UV reduction (grey) versus control males (black).Increment symbol size represents increasing number of observations of males from 1 (smallest) to 24 (largest).
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pone-0019360-g002: Mating success in male sand lizards depending on UV reduction (grey) versus control males (black).Increment symbol size represents increasing number of observations of males from 1 (smallest) to 24 (largest).

Mentions: There was no difference in the mean number of observations of UV-reduced and control males (mean number of re-observations, 2.1±0.24, range 1 to 8, and 1.93±0.24, range 1 to 9, for control and UV-reduced males, respectively; T-test, t = 0.61, P = 0.54). Across treatment and control males, the number of observations of a male after release was correlated with the number of times he was seen courting a female (rs = 0.49, P<0.0001, N = 85). We therefore incorporated male number of re-sightings in our analysis of treatment effects on number of females paired. UV-blocked males had an average of 0.12 female pairing observations per male (±0.049, SE, N = 43), whereas the corresponding number for control males was three times as high (0.31±0.12, N = 42). The regression analysis was globally significant (F3, 81 = 40.7, P<0.0001, R2 = 0.60), and had significant independent effects of treatment (F = 15.4, P<0.0002, d.f. = 1), number of observations (F = 82.9, P<0.0001, d.f. = 1), and their interaction (F = 39.7, P<0.0001; Fig. 2). Body size (SVL) was backwards eliminated from the final model (P>0.25). Our cumulative, ordered logistic regression largely agreed with these results (Global model Likelihood ratio X2 = 35.0, P<0.0001, d.f. = 4). The number of observations of a male significantly affected the number of females he was observed with (Wald X2 = 15.06, P = 0.0001), the treatment x observation interaction remained significant (Wald X2 = 6.03, P = 0.014), while the treatment effect per se fell just short of significant (Wald X2 = 3.07, P = 0.079; Fig. 2).


UV-deprived coloration reduces success in mate acquisition in male sand lizards (Lacerta agilis).

Olsson M, Andersson S, Wapstra E - PLoS ONE (2011)

Mating success in male sand lizards depending on UV reduction (grey) versus control males (black).Increment symbol size represents increasing number of observations of males from 1 (smallest) to 24 (largest).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3094344&req=5

pone-0019360-g002: Mating success in male sand lizards depending on UV reduction (grey) versus control males (black).Increment symbol size represents increasing number of observations of males from 1 (smallest) to 24 (largest).
Mentions: There was no difference in the mean number of observations of UV-reduced and control males (mean number of re-observations, 2.1±0.24, range 1 to 8, and 1.93±0.24, range 1 to 9, for control and UV-reduced males, respectively; T-test, t = 0.61, P = 0.54). Across treatment and control males, the number of observations of a male after release was correlated with the number of times he was seen courting a female (rs = 0.49, P<0.0001, N = 85). We therefore incorporated male number of re-sightings in our analysis of treatment effects on number of females paired. UV-blocked males had an average of 0.12 female pairing observations per male (±0.049, SE, N = 43), whereas the corresponding number for control males was three times as high (0.31±0.12, N = 42). The regression analysis was globally significant (F3, 81 = 40.7, P<0.0001, R2 = 0.60), and had significant independent effects of treatment (F = 15.4, P<0.0002, d.f. = 1), number of observations (F = 82.9, P<0.0001, d.f. = 1), and their interaction (F = 39.7, P<0.0001; Fig. 2). Body size (SVL) was backwards eliminated from the final model (P>0.25). Our cumulative, ordered logistic regression largely agreed with these results (Global model Likelihood ratio X2 = 35.0, P<0.0001, d.f. = 4). The number of observations of a male significantly affected the number of females he was observed with (Wald X2 = 15.06, P = 0.0001), the treatment x observation interaction remained significant (Wald X2 = 6.03, P = 0.014), while the treatment effect per se fell just short of significant (Wald X2 = 3.07, P = 0.079; Fig. 2).

Bottom Line: The role of UV in communication has, however, never been examined.Here we show that when measured immediately after spring skin shedding, there is also signaling in the UV.These results suggest that at least two colour traits in sand lizards, badge area and UV, contribute to rival deterrence and/or female choice on UV characters, which elevates success in mate acquisition in UV intact male sand lizards.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Sydney, Sydney, Australia. mats.olsson@sydney.edu.au

ABSTRACT

Background: Recent work on animal signals has revealed a wide occurrence of UV signals in tetrapods, in particular birds, but also in lizards (and perhaps other Squamate reptiles). Our previous work on the Swedish sand lizard (Lacerta agilis) has verified, both in correlative selection analyses in the wild and with laboratory and field experiments, the importance of the green 'badge' on the body sides of adult males for securing mating opportunities, probably mostly through deterring rival males rather than attracting females. The role of UV in communication has, however, never been examined.

Methodology/principal findings: Here we show that when measured immediately after spring skin shedding, there is also signaling in the UV. By UV-depriving the signal (reflectance) with sun block chemicals fixated with permeable, harmless spray dressing, we show that males in the control group (spray dressing only) had significantly higher success in mate acquisition than UV-deprived males.

Conclusions/significance: These results suggest that at least two colour traits in sand lizards, badge area and UV, contribute to rival deterrence and/or female choice on UV characters, which elevates success in mate acquisition in UV intact male sand lizards.

Show MeSH
Related in: MedlinePlus