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Geographical variation in body size and sexual size dimorphism in an Australian lizard, Boulenger's Skink (Morethia boulengeri).

Michael DR, Banks SC, Piggott MP, Cunningham RB, Crane M, MacGregor C, McBurney L, Lindenmayer DB - PLoS ONE (2014)

Bottom Line: Lizards were sexually dimorphic, whereby females had longer snout-vent length than males, providing support for the fecundity selection hypothesis.Body size variation in M. boulengeri was correlated with temperature and rainfall, a pattern consistent with larger individuals occupying cooler and more productive parts of the landscape.Climate change forecasts, which predict warmer temperature and increased aridity, may result in reduced lizard biomass and decoupling of trophic interactions with potential implications for community organization and ecosystem function.

View Article: PubMed Central - PubMed

Affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.

ABSTRACT
Ecogeographical rules help explain spatial and temporal patterns in intraspecific body size. However, many of these rules, when applied to ectothermic organisms such as reptiles, are controversial and require further investigation. To explore factors that influence body size in reptiles, we performed a heuristic study to examine body size variation in an Australian lizard, Boulenger's Skink Morethia boulengeri from agricultural landscapes in southern New South Wales, south-eastern Australia. We collected tissue and morphological data on 337 adult lizards across a broad elevation and climate gradient. We used a model-selection procedure to determine if environmental or ecological variables best explained body size variation. We explored the relationship between morphology and phylogenetic structure before modeling candidate variables from four broad domains: (1) geography (latitude, longitude and elevation), (2) climate (temperature and rainfall), (3) habitat (vegetation type, number of logs and ground cover attributes), and (4) management (land use and grazing history). Broad phylogenetic structure was evident, but on a scale larger than our study area. Lizards were sexually dimorphic, whereby females had longer snout-vent length than males, providing support for the fecundity selection hypothesis. Body size variation in M. boulengeri was correlated with temperature and rainfall, a pattern consistent with larger individuals occupying cooler and more productive parts of the landscape. Climate change forecasts, which predict warmer temperature and increased aridity, may result in reduced lizard biomass and decoupling of trophic interactions with potential implications for community organization and ecosystem function.

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Related in: MedlinePlus

Sexual differences in body size.Regression analysis showing mean values and 95% confidence intervals for: a) snout-vent length (SVL mm), and b) body mass (g) between male, gravid female and non-gravid female Morethia boulengeri in southern New South Wales.
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pone-0109830-g003: Sexual differences in body size.Regression analysis showing mean values and 95% confidence intervals for: a) snout-vent length (SVL mm), and b) body mass (g) between male, gravid female and non-gravid female Morethia boulengeri in southern New South Wales.

Mentions: Linear regression analysis revealed several significant morphological differences between sexes (Figure 3). Gravid females (N = 26; SVL = 47.39±2.91 mm) had significantly longer SVL than non-gravid females (N = 155; SVL = 43.52±1.23 mm) and males (N = 147; SVL = 41.08±1.25 mm, P<0.001; Figure 3a). Non-gravid females had significantly longer SVL than males (P<0.001). Gravid females (N = 26; mass  = 2.18±0.33 g) had significantly greater body mass than non-gravid females (N = 155; mass  = 1.54±0.15 g), and males (N = 147; mass  = 1.46±0.15 g, P<0.001; Figure 3b). Non-gravid females were marginally heavier than males but this difference was not significant (P = 0.1). Head length (P = 0.6) and head width (P = 0.9) were also not significantly different between sexes.


Geographical variation in body size and sexual size dimorphism in an Australian lizard, Boulenger's Skink (Morethia boulengeri).

Michael DR, Banks SC, Piggott MP, Cunningham RB, Crane M, MacGregor C, McBurney L, Lindenmayer DB - PLoS ONE (2014)

Sexual differences in body size.Regression analysis showing mean values and 95% confidence intervals for: a) snout-vent length (SVL mm), and b) body mass (g) between male, gravid female and non-gravid female Morethia boulengeri in southern New South Wales.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4206273&req=5

pone-0109830-g003: Sexual differences in body size.Regression analysis showing mean values and 95% confidence intervals for: a) snout-vent length (SVL mm), and b) body mass (g) between male, gravid female and non-gravid female Morethia boulengeri in southern New South Wales.
Mentions: Linear regression analysis revealed several significant morphological differences between sexes (Figure 3). Gravid females (N = 26; SVL = 47.39±2.91 mm) had significantly longer SVL than non-gravid females (N = 155; SVL = 43.52±1.23 mm) and males (N = 147; SVL = 41.08±1.25 mm, P<0.001; Figure 3a). Non-gravid females had significantly longer SVL than males (P<0.001). Gravid females (N = 26; mass  = 2.18±0.33 g) had significantly greater body mass than non-gravid females (N = 155; mass  = 1.54±0.15 g), and males (N = 147; mass  = 1.46±0.15 g, P<0.001; Figure 3b). Non-gravid females were marginally heavier than males but this difference was not significant (P = 0.1). Head length (P = 0.6) and head width (P = 0.9) were also not significantly different between sexes.

Bottom Line: Lizards were sexually dimorphic, whereby females had longer snout-vent length than males, providing support for the fecundity selection hypothesis.Body size variation in M. boulengeri was correlated with temperature and rainfall, a pattern consistent with larger individuals occupying cooler and more productive parts of the landscape.Climate change forecasts, which predict warmer temperature and increased aridity, may result in reduced lizard biomass and decoupling of trophic interactions with potential implications for community organization and ecosystem function.

View Article: PubMed Central - PubMed

Affiliation: Fenner School of Environment and Society, ARC Centre of Excellence for Environmental Decisions, and National Environment Research Program, The Australian National University, Canberra, Australia.

ABSTRACT
Ecogeographical rules help explain spatial and temporal patterns in intraspecific body size. However, many of these rules, when applied to ectothermic organisms such as reptiles, are controversial and require further investigation. To explore factors that influence body size in reptiles, we performed a heuristic study to examine body size variation in an Australian lizard, Boulenger's Skink Morethia boulengeri from agricultural landscapes in southern New South Wales, south-eastern Australia. We collected tissue and morphological data on 337 adult lizards across a broad elevation and climate gradient. We used a model-selection procedure to determine if environmental or ecological variables best explained body size variation. We explored the relationship between morphology and phylogenetic structure before modeling candidate variables from four broad domains: (1) geography (latitude, longitude and elevation), (2) climate (temperature and rainfall), (3) habitat (vegetation type, number of logs and ground cover attributes), and (4) management (land use and grazing history). Broad phylogenetic structure was evident, but on a scale larger than our study area. Lizards were sexually dimorphic, whereby females had longer snout-vent length than males, providing support for the fecundity selection hypothesis. Body size variation in M. boulengeri was correlated with temperature and rainfall, a pattern consistent with larger individuals occupying cooler and more productive parts of the landscape. Climate change forecasts, which predict warmer temperature and increased aridity, may result in reduced lizard biomass and decoupling of trophic interactions with potential implications for community organization and ecosystem function.

Show MeSH
Related in: MedlinePlus