Data from: Infrared camouflage in leaf-sitting frogs: A cautionary tale on adaptive convergence

Many green animals that appear cryptic against green leaves also match
leaf reflectance in the near-infrared (NIR). It is unlikely that this NIR
background matching contributes to visual camouflage because animals do
not see NIR light. Two alternative explanations have been proposed –
 infrared camouflage (i.e. matching the temperature of the
background) and thermoregulation – but neither hypothesis has been
experimentally tested. To test these hypotheses, we developed coatings
that manipulate NIR reflectance independently from visible reflectance. We
produced agar frog models that mimic the reflectivity of different species
of leaf-sitting frogs, which are visibly green but differ greatly in NIR
reflectance. We compared heating rates and temperature (surface and core)
of high and low NIR reflectance frog models in the laboratory using a
solar simulator, and in tropical rainforest – the natural habitat of
leaf-sitting frogs. In the laboratory, agar frog models with low
NIR reflectance heated up more quickly and reached higher temperatures
than those with high NIR reflectance. However, in the field, there was no
significant difference between high and low NIR treatments in the
similarity of surface temperature to the adjacent leaves or in core
temperature, thus failing to support the infrared camouflage and
thermoregulation hypotheses, respectively. The lack of difference
between treatments is likely due to the limited exposure of frogs to
direct solar radiation in their natural habitats. We propose a
non-adaptive explanation for NIR background matching based on specific
mechanisms underlying green coloration and translucence in frogs and
caution against assuming adaptive convergence.