Evolution of antipredator behavior in an island lizard species, Podarcis erhardii (Reptilia: Lacertidae): The sum of all fears?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110598/1/evo12555.pd

Eat or be eaten? An observation of Podarcis erhardii consuming Scolopendra cingulata from Andros Island, Cyclades, Greece

Podarcis wall lizards mainly feed on coleopterans, orthopterans, arachnids, and other small invertebrates. However, Aegean wall lizards, Podarcis erhardii, are widely distributed across Aegean islands and are increasingly observed eating non-traditional food items ranging from plant material to conspecific eggs and body parts. Here, we report the first documented case of P. erhardii consuming a large centipede, Scolopendra cingulata. The predator-prey relationship between these species has appeared to go both ways and may intensify on islands

Color Polymorphism is a Driver of Diversification in the Lizard Family Lacertidae.

Color polymorphism-two or more heritable color phenotypes maintained within a single breeding population-is an extreme type of intraspecific diversity widespread across the tree of life. Color polymorphism is hypothesized to be an engine for speciation, where morph loss or divergence between distinct color morphs within a species results in the rapid evolution of new lineages, and thus, color polymorphic lineages are expected to display elevated diversification rates. Multiple species in the lizard family Lacertidae are color polymorphic, making them an ideal group to investigate the evolutionary history of this trait and its influence on macroevolution. Here, we produce a comprehensive species-level phylogeny of the lizard family Lacertidae to reconstruct the evolutionary history of color polymorphism and test if color polymorphism has been a driver of diversification. Accounting for phylogenetic uncertainty with multiple phylogenies and simulation studies, we estimate an ancient origin of color polymorphism (111 Ma) within the Lacertini tribe (subfamily Lacertinae). Color polymorphism most likely evolved few times in the Lacertidae and has been lost at a much faster rate than gained. Evolutionary transitions to color polymorphism are associated with shifts in increased net diversification rate in this family of lizards. Taken together, our empirical results support long-standing theoretical expectations that color polymorphism is a driver of diversification.[Color polymorphism; Lacertidae; state-dependent speciation extinction models; trait-dependent diversification.]

Data from: Feed or fight: testing the impact of food availability and intraspecific aggression on the functional ecology of an island lizard

Body size often varies among insular populations relative to continental conspecifics – the ‘island rule’ – and functional, context-dependent morphological differences tend to track this body size variation on islands. Two hypotheses are often proposed as potential drivers of insular population differences in morphology: one relating to diet and the other involving intraspecific competition and aggression. We directly tested whether differences in morphology and maximum bite capacity were explained by interisland changes in hardness of both available and consumed prey, and levels of lizard-to-lizard aggression among small-island populations. Our study included 11 islands in the Greek Cyclades and made use of a gradient in island area spanning five orders of magnitude. We focused on the widespread lizard Podarcis erhardii. We found that on smaller islands, P. erhardii body size was larger, head height was larger relative to body size, and maximum bite capacity became proportionally stronger. This pattern in morphology and performance was not related to differences in diet, but was highly correlated with proxies of intraspecific aggression – bite scars and missing toes. Our findings suggest that critical functional traits such as body size and bite force in P. erhardii follow the predictions of the island rule and are changing in response to changes in the competitive landscape across islands of different sizes

Feed or fight: testing the impact of food availability and intraspecific aggression on the functional ecology of an island lizard

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137218/1/fec12550.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137218/2/fec12550-sup-0001-LaySummary.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137218/3/fec12550_am.pd

Data from: Evolution of antipredator behavior in an island lizard species, Podarcis erhardii (Reptilia: Lacertidae): the sum of all fears?

Organisms generally have many defenses against predation yet may lack effective defenses if from populations without predators. Evolutionary theory predicts that ‘costly’ antipredator behaviors will be selected against when predation risk diminishes. We examined antipredator behaviors in Aegean wall lizards, Podarcis erhardii, across an archipelago of land-bridge islands that vary in predator diversity and period of isolation. We examined two defenses, flight initiation distance and tail autotomy. Flight initiation distance generally decreased with declining predator diversity. All predator types had distinctive effects on flight initiation distance with mammals and birds having the largest estimated effects. Rates of autotomy observed in the field were highest on predator-free islands yet laboratory-induced autotomy increased linearly with overall predator diversity. Against expectation from previous work, tail autotomy was not explained solely by the presence of vipers. Analyses of populations directly isolated from rich predator communities revealed that flight initiation distance decreased with increased duration of isolation in addition to the effects of current predator diversity, whereas tail autotomy could be explained simply by current predator diversity. Although selection against costly defenses should depend on time with reduced threats, different defenses may diminish along different trajectories even within the same predator-prey system

Autotomy data

This file contains field autotomy and laboratory autotomy dat from all of our study sites. These data were used to construct models of both field and laboratory autotomy

Donihue et al. 2015 Feed or Fight Data

All data archived here were used for analyses in Donihue et al. "Feed or Fight: Testing the impact of food availability and intraspecific aggression on the functional ecology of an island lizard." Data is in five worksheets. Please see ReadMe file for additional information