Neutral arena setup
Males were allowed to acclimate in captivity for 7 days prior to staging
the pairwise contests (Bohórquez-Alonso et al. 2018). The contests were
staged in a neutral arena to remove the effect of residency (Sacchi et
al. 2009; Abalos et al. 2016), and in a small confined room, free of
noises and other distractions. The 42 males were paired by similarity in
body mass (mean mass difference = 0.64 g) and never exceeding an SVL
difference of 2 mm between them (mean SVL difference = 0.72 mm)
(Bastiaans et al. 2013). This removes the size effect, which is not an
objective of the present study, but is an important predictor of
dominance in lizards (e.g. Sacchi et al. 2009). Contestant males were
transferred into an artificial arena that was 60 cm width x 80 cm length
x 48 cm height which was set up with sandy substrate covering the
bottom. The arena was made up of acrylic sheets and covered on three
sides while the fourth side was left uncovered for behavioral recording
using a digital video camera. A 75W thermal lamp was set up directly
above a central rock. The arena was divided into two parts at the
beginning of each trial using a removable partition of opaque plastic.
The trials took place on 5 consecutive days between the
30th of May and 3rd of June 2014
from 8:00 am to 6:00 pm. Each lizard was placed at opposite ends of the
partition and allowed 5 minutes to acclimate to their space. After this
acclimation period the partition between the two sides of arena was
removed and the behavior of the lizards was filmed for 20 minutes
without any human presence in the room. Before each subsequent trial,
sand substrate was changed to avoid the effects of any olfactory cues
from previous trial (Bastiaans et al. 2013). We visualized the videos
and noted every behavior shown by contesting lizards.