Size evolution in island lizards

By Shai Meiri. 2007

152 citations recorded by the source corpus.

Aim The island rule, small animal gigantism and large animal dwarfism on islands, is a topic of much recent debate. While size evolution of insular lizards has been widely studied, whether or not they follow the island rule has never been investigated. I examined whether lizards show patterns consistent with the island rule. Location Islands worldwide. Methods I used literature data on the sizes of island–mainland population pairs in 59 species of lizards, spanning the entire size range of the group, and tested whether small insular lizards are larger than their mainland conspecifics and large insular lizards are smaller. I examined the influence of island area, island isolation, and dietary preferences on lizard size evolution. Results Using mean snout–vent length as an index of body size, I found that small lizards on islands become smaller than their mainland conspecifics, while large ones become larger still, opposite to predictions of the island rule. This was especially strong in carnivorous lizards; omnivorous and herbivorous species showed a pattern consistent with the island rule but this result was not statistically significant. No trends consistent with the island rule were found when maximum snout–vent length was used. Island area had, at best, a weak effect on body size. Using maximum snout–vent length as an index of body size resulted in most lizard populations appearing to be dwarfed on islands, but no such pattern was revealed when mean snout–vent length was used as a size index. Main conclusions I suggest that lizard body size is mostly influenced by resource availability, with large size allowing some lizard populations to exploit resources that are unavailable on the mainland. Lizards do not follow the island rule. Maximum snout–vent length may be biased by sampling effort, which should be taken into account when one uses this size index.

Subfields: Ecological Modeling, Ecology, Evolution, Behavior and Systematics, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/f827af1384ea836bf73066c74ef2b5410ff94a06

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Citations in the corpus

Length-weight allometries in lizards (2010, background): “Reptile size data are more often presented as maxima than as means (Meiri, 2008) and maxima are sensitive to sample size (Stamps & Andrews, 1992; Meiri, 2007).”
Dinosaurs and the island rule: The dwarfed dinosaurs from Haţeg Island (2010, background): “…other Haţeg dinosaurs may simply indicate that, while dwarfing is common and is related to isolation on a small island, it is not an absolute rule to which all species adhere, a case that has been made forcefully for modern mammals and lizards (Meiri et al., 2004, 2006; Meiri, 2007; and see above).”
Late Quaternary reptile extinctions: size matters, insularity dominates (2016, background): “Small sample sizes of extinct taxa may also mask their true size maxima, making them appear smaller than they really were (Meiri, 2007).”
Evolution and ecology of lizard body sizes (2008, methodology): “Lizards are likewise thought to grow large on islands where large prey or abundant food sources exist (Case & Schwaner, 1993; Raia & Meiri, 2006; Meiri 2007).”
Is the island rule general? Turtles disagree (2014, methodology): “The major reptilian groups, lizards and snakes, seem to show inconsistent patterns of insular body size evolution (cf. Boback & Guyer, 2003; Meiri, 2007).”
Are lizards feeling the heat? A tale of ecology and evolution under two temperatures (2013, background): “hence different insular environments select for a plethora of phenotypes rather than for a single optimum (Meiri, 2007; Thomas et al., 2009; Raia et al., 2010; Pafilis et al., 2011).”
The island syndrome in lizards (2013, methodology): “We estimated female and hatchling masses from snout–vent lengths (SVLs) using family-specific equations for legged species, and different equations for legless and leg-reduced lizards from Meiri (2010) except for the following: for Liolaemus and Phymaturus we used equations from Pincheira-Donoso et ”
Extinct, obscure or imaginary: The lizard species with the smallest ranges (2017, unknown): “Coupled with small sample size, this will automatically result in small inferred body sizes (Meiri, 2007).”
Slaying dragons: limited evidence for unusual body size evolution on islands (2011, background): “Currently we are unable to sufficiently explain why this pattern prevails, or why it holds only for birds, and only within genera, and note that species maximum sizes [probably an inferior size measure because it is more sensitive to sample size (Meiri, 2007) but representing about 7% more species (”