This repository contains code and data needed to reproduce the article:
Yu, X., Wu N. C., Zhang Z., Lei J. (In submission) Malar stripe increases hunting efficiency for a diurnal predator under bright conditions.
Raw data
exp_raw_data.csv- Raw experimental data used for the analysis.malar_snake_phylogeny.csv- Raw comparative data used for the phylogeny analysis.squam_shl_new.tre- Phylogeny from Tonini et al (2016).
Code
malar_exp_analysis.R- Code to clean and analyse experiment data, and produce figures.malar_comp_analysis.R- Code to clean and analyse phylogeny data, and produce figures.
Extra files
- To add.
The presence of a dark stripe around the eye, known as ‘malar stripe’, has various functions across the animal kingdom. Most predominately to reduce glare for diurnal predators under sunlit conditions. This ‘solar glare hypothesis’ is mostly supported for endotherms such birds and mammals. However, malar stripes are also present in many ectotherms such as snakes, yet the solar glare hypothesis has not been tested beyond endotherms. We performed a series of predation experiments with a diurnal ectothermic hunter, Elaphe dione with and without malar stripes under different light conditions (50, 2,500, and 5,000 Lm), as well as examined the phylogenetic relationship between malar stripes and activity patterns (diurnal, nocturnal, or both) of 3,564 snake species, an evolutionary diverse taxonomic group. Relative to malar stripes present, we show E. dione with the malar stripe painted out took 3.5 times longer to strike prey and had 25% lower predation success under high light conditions. Hidden Markov models suggest the transition rates from no malar stripe to the presence of malar stripe was eight times faster when snakes hunted diurnally, while the transition from malar stripe to no malar stripe was seven times higher when snakes hunted nocturnally. The evolution of malar stripes in snakes appears to be facilitated by diurnal activity and may help increase predation success under sun-lit conditions.
Keywords: animal colouration, malar stripe, predation, Serpentes, solar glare
This repository is provided by the authors under the MIT License (MIT).