Wang, I. J. | bioRxiv Science

bioRxiv2024

Throat color polymorphism is related to differences in aggression in the Aegean wall lizard

Aggressive behavior can be used to establish and maintain access to crucial resources such as space, food, and mating opportunities. Color polymorphic animals sometimes exhibit morph-correlated aggressive behaviors that can influence relative reproductive success and, thus, the maintenance of polymorphism. The Aegean wall lizard, Podarcis erhardii, exhibits three monochromatic throat color morphs: orange, white, and yellow. Previously, male P. erhardii color morphs were shown to differ in their use of aggressive behaviors and ability to win staged contests during laboratory experiments. However, whether these color morphs use aggressive behavior differently in their natural setting where ecological and environmental factors are not standardized remains unknown. Here, we used in situ observations of wall lizard color morph interactions over a large section of dry stone wall to investigate behavioral differences in aggression among color morphs in situ. We compared the counts and intensities (aggression scores) of aggressive behaviors (both performing and receiving aggression) among color morphs and found that color morphs differ significantly in the frequencies and intensities of their aggressive behaviors. We found that the white morph exhibited significantly more aggression than the orange and yellow morphs on dry stone walls. Taken together, results from in and ex situ behavioral studies suggest that the smaller, more common white color morphs are more aggressive, which might help explain their relatively greater abundance and persistence across the species range.

animal behavior and cognition↗

bioRxiv2022

Some like it hotter: differential thermal preferences among lizard color morphs

Temperature rules the lives of ectotherms. To perform basic biological functions, ectotherms must make behavioral adjustments to keep their body temperatures near a preferred temperature (Tpref). Many color polymorphic lizards are active thermoregulators and exhibit morph differences in traits related to thermoregulation, such as color, body size, and microhabitat use. The Aegean wall lizard, Podarcis erhardii, is a heliothermic lizard with orange, white, and yellow color morphs that differ in size, behavior, and microhabitat use. Here, we tested whether P. erhardii color morphs from the same population from Naxos island, Greece, differ in Tpref. We hypothesized that orange morphs would prefer lower temperatures than white and yellow morphs because orange morphs are often found on cooler substrates and in microhabitats with more vegetation cover. We obtained Tpref for 95 individuals using laboratory thermal gradient experiments of wild-caught lizards and found that orange morphs do, indeed, prefer significantly cooler temperatures, regardless of body size differences. Average orange morph Tpref was 2.3 {o}C lower than average white and yellow morph Tpref. Our results add support to the idea that P. erhardii color morphs have multivariate alternative phenotypes and present the possibility that thermally heterogeneous environments play a role in the maintenance of color polymorphism in this species.

zoology↗